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  • 1995-1999  (1,719)
  • 1999  (60)
  • 1996  (1,659)
  • Engineering General  (686)
  • Inorganic Chemistry  (602)
  • Life Sciences  (431)
  • 1
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 225-233 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The potential of using indigenous microorganisms in beach sediments to degrade petroleum hydrocarbons emanating from marine oil spillages in the Straits of Singapore was investigated. A field trial was conducted using oil contaminated beach sediments from Pulau Semakau - a small island 15 km south of Singapore. The results clearly show that the addition of inorganic nutrients to beach sediments significantly enhanced the activity of indigenous microorganisms (measured using the dehydrogenase enzyme assay and viable cell count techniques), as well as the removal of total recoverable petroleum hydrocarbons (TRPH) over a 50-day study period (with up to 44% in the case of nutrient addition). The potential of exploiting in-situ bioremediation techniques for oil spill clean-up operations in tropical marine environments is discussed.
    Additional Material: 3 Ill.
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  • 2
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The biosynthesis of bacterial cellulose by Acetobacter xylinum was optimized by numerically finding the maximum of an arbitrarily chosen second order polynomial model function of several variables (describing the dependence of the cellulose production on the concentrations of the medium components), using multivariable linear regression analysis. The chosen function appeared to describe the analyzed correlation sufficiently well. Consequently, three to six stages of optimization made the determination of the optimum medium compositions possible for 16 days of fermentation at 30°C in a medium based on fructose (wt%: fructose, 3.68; yeast extract, 5.02; (NH4)2NO3, 0.001; KH2PO4, 0.3; MgSO4 × 7 H2O, 0.05; resulting in a cellulose production equal to 0.505 wt.% - namely 5.6 times higher than before the optimization) and for 7 days fermentations at 30°C in a medium based on sucrose and ethanol (wt.%: sucrose, 5.0; ethanol, 1.36; yeast extract, 1.27; (NH4)2SO4, 0.5; KH2PO4, 0.3; MgSO4 × 7 H2O, 0.05; resulting in a cellulose production equal to 0.251 wt.% - namely 1.5 times higher than before the optimization).
    Additional Material: 1 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 91-100 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The stability of a polyphenol oxidase (PPO) preparation from the white-rot fungus Trametes versicolor during a process for the enzymatic decrease of the phenolic content of commercial canola meal (CM) was investigated. The effects of temperature, pH, protein origin and concentration, and meal particles were considered. The results showed that the thermal stability of the enzyme preparation was significantly increased in the presence of CM. The half-life times for the enzyme preparation, pre-incubated with CM at 50, 60, 70 and 75°C, were 45, 10.5, 3.5 and 1.5 hours, respectively; this represents an increase in the thermal stability of the enzyme preparation of up to four times in the presence of CM compared to the stability in the absence of CM. This effect was caused by the protective actions of both the CM particles and CM proteins, with the former responsible for 90% of the observed effect. The thermal stability of the enzyme in the presence of CM, from which 20% of the extractable proteins was extracted, was 5% lower compared to the stability in the presence of untreated CM. Changes in pH level from 5.0 to 3.2 resulted in a loss of stability comparable to that observed when the pre-incubation temperature was increased from 50 to 70°C.A semi-empirical model describing the changes in the concentration of the active enzyme pre-incubated in the presence and absence of CM at various incubation temperatures was proposed. A very good agreement between the model and experimental data was obtained. The proposed model, together with a general set of model parameters, can be used as a tool for the optimization of a process for the upgrade of CM by enzymatically decreasing the meal's phenolic content.
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 111-145 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A non-comprehensive review of several technical developments in the field of aerobic biological waste-water treatment engineering is carried out, considering the active role the engineers have to play in this field. This paper brings together conventional and advanced problems in the field of aerobic biological waste-water treatment.Such an overview of biological waste-water treatment also precedes comments on some important aspects concerning the microorganisms responsible for waste-water treatment as well as considerations of the application of fundamentals and kinetics to the analysis of the biological processes used most commonly for aerobic biological waste-water treatment.A survey of the development of the biological activated-sludge process and some modifications are given. Some problems implied in the conventional activated-sludge waste-water treatment are analyzed, considering conventional processes and bioreactor models (the continuous stirred-tank reactor model and the plug-flow reactor models of the activated-sludge process) as well as aerated lagoons.Further, modifications of the activated-sludge process are presented. These include additional details on the bioreactor progress and applications, with emphasis on aspects concerning airlift bioreactors and their variants, deep-shaft bioreactors and reciprocating jet bioreactors which are considered as the third generation of bioreactors owing to their important advantages in design, operation and performance in waste-water treatment. Sequencing-batch reactors and aerobic digestion processes, including conventional aerobic digestion, high-purity oxygen digestion, thermophilic aerobic digestion and cryophylic aerobic digestion are also reviewed.Finally, some aspects regarding the operational factors that are involved in the selection of the reactor type are included.
    Additional Material: 11 Ill.
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  • 5
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the first part of the experiments, the mechanical properties of 1%, 2% and 3% carrageenan and 1%, 2% and 3% carrageenan/locust bean gum (LBG) gels stored in various concentrations of propionic and acetic acids and their mixtures were examined. The stability of these materials was measured by uniaxial compression between two parallel plates using the Instron Universal Testing Machine. A mathematical model explaining the dependence of the destroying force on the storage time was chosen for data analysis. Using this model, the average rate of gel deterioration was calculated. The structural properties of the examined gels were most influenced by the highest concentration of propionic and acetic acids and their mixtures (1% acetic acid and 2% propionic acid). The addition of LBG to carrageenan decreased the gel destroying force and increased its resistance to acids.In the second part of the experiments, the Propionibacterium freudenreichii subsp. shermanii NCFB 1081 and NCFB 566 were immobilized in a living state in 1%, 2% and 3% carrageenan and 1%, 2% and 3% carrageenan/LBG gels. The ammonia consumption, glucose utilization, production of propionic and acetic acids and the biosynthesis of vitamin B12 were examined. An increase in the productivity of propionic acid and a significant decrease in the vitamin B12 produced in the biosynthesis were observed when immobilized cells were used. The immobilization of cells enhanced the productivity of propionic acid by up to 40% compared to free cells. The best results were obtained for the second and third applications of immobilized cells in all concentrations of carrageenan gels and 2% and 3% carrageenan/LBG gels The results showed that carrageenan/LBG is a better support material for the immobilization of propionic acid bacteria than the pure carrageenan.
    Additional Material: 2 Ill.
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  • 6
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 171-177 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The bioaccumulation of cadmium by the white rot fungus Pleurotus sajor-caju onto dry biomass was investigated using aqueous media with concentrations in the range of 0.125 mM-1.0 mM The highest cadmium uptake (between 88.9 and 91.8%) was observed with aerobic fungal biomass from the exponential growth phase. Up to 1.0 mM cadmium gradually inhibited mycelium development, but never blocked it completely. Freeze-dried, oven-dried and non-metabolizing live Pleurotus sajor-caju biomass types were tested for their capacity to adsorb the test ion Cd2+ within the pH range of 4.5 to 6.0. Freeze-dried biomass proved to be the most efficient biomass type for Cd2+ metal adsorption. Therefore, Pleurotus sajor-caju may be used for heavy metal removal and bioremediation.
    Additional Material: 2 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 3-16 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of cellobiose hydrolysis was studied using β-glucosidase from Penicillium funiculosum, both free and immobilized on nylon powder, at different temperatures, pH values, enzymatic activities and initial cellobiose and glucose concentrations.The experimental results were fitted to a kinetic model by considering the substrate and product inhibitions as well as the thermal deactivation of β-glucosidase with a mean deviation of less than 10%. The immobilization of β-glucosidase led to an increase in the stability of the enzyme against changes in the pH value.
    Additional Material: 10 Ill.
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  • 10
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 27-36 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ethanol has been reported to be a gaseous pollutant, originating from the agricultural industry. Interest in its biodegradation has increased over the last two decades. Most of the current studies have focused on its elimination by mixed cultures. This study is part of a broader project intended to utilize Candida utilis strains for gaseous ethanol elimination and to eventually bioconvert them into biomass and/or volatile metabolites. We present here the study of six strains (one from the ATCC and five from the ICIDCA collection) cultivated in a liquid medium, with initial ethanol concentrations of 16 g/l and 32 g/l. At 16 g/l, a maximum ethanol elimination rate of 0.13 g/l × h was obtained in four of the six strains (ATCC 9950, L/375-1, L/375-5 and L/375-10). This rate increased to 0.21 g/l × h with an initial ethanol concentration of 32 g/l. The L/375-5 strain was the best biomass producer (3.3 g/l) at 32 g/l, while the highest ethyl acetate production (0.80 g/l) was obtained with the L/375-1 strain. The L/375-25 and L/375-26 strains which showed very low ethyl acetate production were, by way of contrast, efficient acetaldehyde producers, with 0.54 g/l and 0.66 g/l measured in the broth. While biomass production reached its maximum after two days of culture, the production of acetic acid and ethyl acetate continued during the third day. The results for biomass and metabolite production obtained with the ICIDCA collection strains (L/375-1, L/375-5 and L/375-10) were better than those obtained with the ATCC 9950 strain, although the latter often has been reported to be particularly suitable for metabolite production.
    Additional Material: 5 Ill.
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  • 12
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 77-78 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 59-68 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The ability of the Rhizobium sp., isolated from the root nodules of the leguminous pulse yielding shrub Cajanus cajan, to produce extracellular polysaccharides (EPS) was checked. A large amount of EPS (1, 128 μg/ml) was produced by the bacteria in yeast extract mannitol medium. Growth and EPS production started simultaneously, but the production reached its maximum level in the stationary phase of growth at 28 h. The EPS production by this Rhizobium sp. was much higher than by many other strains from nodules of Cajanus cajan which took a much longer time to reach maximum EPS production than this strain. The maximum EPS production (2,561 μg/ml) was obtained when the medium was supplemented with mannitol (1%), cetyl pyridinium chloride (2 μg/ml) and KNO3 (0.2%), in which the production was increased by 276% compared to the control. The EPS production rose in the period up to 65 h with increased mannitol concentration. The EPS contained arabinose, xylose and rhamnose monomers. The possible role of rhizobial EPS production in root nodule symbiosis is discussed.
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  • 14
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 331-339 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Rhizobium sp., isolated from the root nodules of the leguminous fodder herb Melilotus alba, produced large amounts of extracellular polysaccharides (EPS) (963.5 μg/ml) in a yeast extract mannitol medium. Growth and EPS production started simultaneously, but EPS production reached its maximum during the stationary phase of growth of the bacteria, at 20 hours. EPS production was increased with all of the thirteen sugars tested. Different nitrogen sources, such as nitrates, glutamic acid, casamino acid and L-asparagine, increased the EPS production although it was inhibited by glycine, nitrite and ammonium salts. Among the vitamins and metal ions, only pyridoxal phosphate and ZnSO4 promoted EPS production. Attempts were made to optimize the cultural requirements for growth and maximum EPS production. Maximum EPS production (1457.0 μg/ml) was obtained when the medium was supplemented with glucose (1%), pyridoxal phosphate (2 μ g/ml), ZnSO4 × 7 H2O (10 μg/ml) and glutamic acid (0.1%). Under these conditions, the production was increased by 254.3% compared to the control. The EPS contained arabinose, xylose and rhamnose monomers. The presence of arabinose and xylose in the EPS produced by a Rhizobium sp. was uncommon.
    Additional Material: 2 Ill.
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  • 17
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the present work, the use of flame-burned WS as carriers of Z. mobilis and extracellular levansucrase and the effect of the cell fixation method by dehydration on system productivity were investigated. Lyophilization and convective drying of Z. mobilis biomass at 30°C to a moisture content of 10-14% gave the best results for the repeated batch fermentations of a sucrose medium to obtain levan and ethanol. Significant correlation between the product formation and the concentration of free cells in the fermentation medium was established. Clearly, the cells were weakly bound to the newly generated WS and were washed out into the medium during fermentation. Here the hypothesis is presented that components excreted from damaged cells during dehydration can intensify the reactivation of damaged living cells and influence the interactions between the cells and the wire surface.The passive immobilization of extracellular levansucrase in oxidized WS was also observed. The superiority of oxidized WS in comparison with non-treated WS is related to an increase in the number of OH groups. The potential regeneration of WS by burning after the termination of fermentation cycles was also considered.
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  • 18
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 146-146 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 19
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 157-161 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A xylanase was removed from crude extract of the fungus Penicillium janthinellum under optimized conditions: 0.10M phosphate buffer, pH 7.0, 0.2 M BDBAC (N-benzyl-N-dodeceyl-N-bis (2-hydroxyethyl) ammonium chloride), 7.5% hexanole, 30°C and an agitation time of 1 minute. At 1.42 mg per ml protein concentration, 73% of the xylanase activity was recovered and a 7-fold enrichment factor was obtained. The enzyme had a molecular weight (MW) of 20.1 kDa and the isoelectric point (PI) revealed the presence of two protein bands with a PI of 6.0 and 6.5. The optimum pH and optimum temperature were 4.2 and 50°C, respectively. The low pH differential between the aqueous medium and the protein PI seemed to influence the xylanase transportation into the reversed micelles.
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  • 20
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 21
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 163-169 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The morphogenetic response of Hypericum perforatum seedlings to different auxin and cytokinin concentrations was studied. A stimulation of the concentration-dependent rooting ability was observed under the influence of indole-3-acetic acid and indole-3-butyric acid. Rooting was not enhanced by the effects of 2,4-dichlorophenoxyacetic acid and 1-naphtaleneacetic acid. Differentiated roots were isolated and cultured in liquid media with the same combination of growth-promoting auxins. Chromosome counts in root tip cells after long-term cultivation indicated a high degree of chromosomal instability. Multiple shoot formation occurred under the influence of 6-benzylaminopurine and kinetin. Adenine and 6-(γ,γ-dimethylallylamino)-purine did not stimulate shoot differentiation. No differences in the morphogenetic response to auxins and cytokinis were detected between diploid and tetrapoloid plants.
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  • 22
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999) 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 23
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 179-186 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Spores of Aspergillus niger were exposed to a pulsed electric field. After treatment by the electric field, the viability of the conidia of A. niger varied depending on the field strength, pulse width and frequency. In all cases, these parameters reduced the viability rate of the conidia from 2.0 × 107 to a range from 6.2 × 106 to 8.5 × 106 spores/ml (3.1 to 42.6%). After pulse treatment, the conidia were used as the inoculum for citric acid fermentation in shake flasks. The highest increase in citric acid yield (about 1.4-fold) was reached at a field strength of 2.85 kV/cm, a frequency of 1 Hz and a pulse width of 1 ms. When the parameters of the electric field increased there were important changes in the respiration rate of the Aspergillus niger mycelium (48-h-old) after electric shock treatment. The highest consumption of dissolved oxygen (22.9%) in the medium by Aspergillus niger mycelium was observed at an electric field strength of 2.85 kV/cm, a 1 Hz frequency, a pulse width of 1 ms and a 1-min exposure period. It seems that an electric-field stimulation of the conidia prior to inoculation may offer an important method of improving the efficiency of citric acid. The treatment of the conidia is both simple from the technical point of view and extremely rapid.
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  • 24
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 25
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of adding some inducers of lignolytic activity to semi-solid-state cultures of Phanerochaete chrysosporium BKM-F-1767 (ATCC 24725) were investigated. The inducers assayed were veratryl alcohol and solid manganese (IV) oxide. The microorganism was cultured on corncob, which functioned both as physical support and source of nutrients.Supplementing the cultures with veratryl alcohol created the situation where manganese-dependent peroxidase (MnP) and lignin peroxidase (LiP) activities of approximately 1,500 U/l and 200 U/l, respectively, could be attained. These activities were considerably higher than those obtained in the reference cultures (about 5 and 4-fold).In the same way, the addition of manganese (IV) oxide led to MnP and LiP activity levels of about 2,000 U/l and 300 U/l, respectively. These activities were also notably above (about 6 and 5-fold, respectively) those achieved in the reference cultures.Moreover, laccase activity (around 200 U/l) was only detected in veratryl alcohol or manganese (IV) oxide supplemented cultures.
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  • 26
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 27
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    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 45-56 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The culture behaviour of Thermus aquaticus was characterized. The response of the bacterium to various carbon (tryptone, glucose, glycerol) and nitrogen sources (yeast extract, NaNO3, (NH4)2SO4, leucine, thymine, thiamine, glutamic acid) was studied. Amino acids did not support growth, but CASTENHOLZ salt medium supplemented with yeast extract and glucose or tryptone resulted in good growth and production. A suitable medium composition giving the highest biomass concentration and enzyme yield was developed. The simple medium containing TYE-NaCl resulted in the highest biomass concentration, whereas CASTENHOLZ mineral medium supplemented with tryptone and yeast extract gave the highest specific activity and enzyme yield. The effect of inoculum age and size on growth was also investigated in order to improve the yield and process consistency. The use of shake flasks inoculated with precultures at their early or late stationary phase resulted in the same biomass concentration (0.56 ± 0.015 g/l) and similar maximum specific growth rates (0.258 ± 0.003 h-1). Inoculum sizes between 1 and 2.5 per cent were optimal for cell growth. As the other papers on thermophilic microorganisms, including the T. aquaticus YT-1 strain, gave qualitative information on growth, the results presented here cannot be compared with others on a quantitative basis. TaqI endonuclease was purified using a 5 step protocol including cell disruption, adsorption, precipitation, column chromatography and final dialysis. The enriched fraction had a specific activity of 33,600 U TaqI endonuclease per mg protein.
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  • 28
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 88-88 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 29
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 79-86 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Methylobacterium rhodesianum MB 126, a pink-pigmented facultatively methylotrophic bacterium that uses that serine pathway for the assimilation of reduced C1 compounds, is able to produce poly-3-hydroxybutyrate (PHB) under certain limitation conditions. Mutants of this bacterium, which were isolated after the treatment with sodium nitrite, are impaired in their ability to synthesize PHB, but produce another polymer in addition to PHB, namely an exopolysaccharide (EPS). This paper attempts to explain this surprising behaviour.
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  • 30
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 31
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999) 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 32
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 37-44 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Agar-agar, agarose, carrageenan and calcium alginate were used for the immobilization of Dunaliella salina cells. Out of the four, agar-agar was found to be the most effective and therefore the study was carried out on it using different pH values ranging from 6 to 10 and cell densities from 0.1 to 0.8 μg chlorophyll (chl, a) per bead to find which are is best suited for glycerol production. The maximum glycerol production of 9.2 μM/mg chl a was recorded in agar-agar immobilized algae and this was followed by 8.4 μM/mg chl a in calcium alginate. The maximum cell number 6.2 × 109/ml and the specific growth rate (μ) of 0.80 l/day were reached at pH 8 in agar-agar immobilized algae. It was shown that the maximum amount of glycerol was produced when the cell density was 0.8 μg chl a/ block. Changing the medium after 24 hours affected the rate of glycerol production at different pH values. Using a cell density of 0.8 μg chl a/block at 16 W/m2 light intensity increased the glycerol production in comparison with the use of free living cells.
    Additional Material: 4 Ill.
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  • 33
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 235-250 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new low-cost β-galactosidase (lactase) preparation for whey permeate saccharification was developed and characterized. A biocatalyst with a lactase activity of 10 U/mg, a low transgalactosylase activity and a protein content of 0.22 mg protein/mg was obtained from a fermenter culture of the fungus Penicillium notatum. Factors influencing the enzymatic hydrolysis of lactose, such as reaction time, pH, temperature and enzyme and substrate concentration were standardized to maximize sugar yield from whey permeate. Thus, a 98.1% conversion of 5% lactose in whey permeate to sweet (glucose-galactose) syrup was reached in 48 h using 650 β-galactosidase units/g hydrolyzed substrate. After the immobilization of the acid β-galactosidase from Penicillium notatum on silanized porous glass modified by glutaraldehyde binding, more than 90% of the activity was retained. The marked shifts in the pH value (from 4.0 to 5.0) and optimum temperatures (from 50°C to 60°C) of the solid-phase enzyme were observed and discussed. The immobilized preparation showed high catalytic activity and stability at wider pH and temperature ranges than those of the free enzyme, and under the best operating conditions (lactose, 5%; β-galactosidase, 610-650 U/g lactose; pH 5.0; temperature 55°C), a high efficiency of lactose saccharification (84-88%) in whey permeate was achieved when lactolysis was performed both in a batch process and in a recycling packed-bed bioreactor. It seems that the promising results obtained during the assays performed on a laboratory scale make this immobilizate a new and very viable preparation of β-galactosidase for application in the processing of whey and whey permeates.
    Additional Material: 6 Ill.
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  • 34
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 35
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 263-272 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: An acid α-amylase hyperproducing strain, designated as MIR-61, was isolated in a screening procedure from South American soil samples. MIR-61, a 60°C thermoresistant strain, was identified using 98 biochemical and morphological tests and characterized as Bacillus licheniformis by numerical taxonomy. Batch cultures of B. licheniformis MIR-61 showed extracellular α-amylase and α-glucosidase activities during the exponential growth phase.The production of α-amylase was studied at free and constant pH values at 37 and 45°C. Maximum α-amylase activity (4,767 kU/dm3 in a liquid medium) was detected at 45°C at a constant pH (7.0) in the late exponential phase. The α-amylase production by B. licheniformis MIR-61 is 10 to 300 times higher than the enzyme production reported in strains of the same species.Optimum α-amylase activity was found at 50 to 67°C in an acid pH range from 5.5 to 6.0. These properties would allow its use in starch industry processes.
    Additional Material: 4 Ill.
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  • 36
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999) 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 37
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 38
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 279-292 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The continuous aerobic degradation of phenoxyalkanoate herbicides by Sphingomonas herbicidovorans MH was investigated in a bubble reactor filled with modified polyurethane-foam (PU 90/51) as a carrier for the adsorptive immobilization of the bacterial cells. The PU-foam was applied in the form of plates (5 × 10 × 10 mm) and the amount added was equivalent to a PU-load of 1.25% [w/v]. Strain MH is capable of detoxifying the dichloro-substituted phenoxyalkanoates 2,4-DP, 2,4-D and 2,4-DB and the methylchloro-substituted phenoxyalkanoates MCPA, MCPP and MCPB. Degradation of the respective substrate was followed by HPLC analyses and by determination of the chloride release. No intermediates of the degradation pathways or “dead end” products were detected by HPLC analyses. The PU-bubble reactor with immobilized 2,4-DP-pre-grown cells was run continuously at 30°C at the high dilution rate of D = 0.5h-1 with 2,4-DP (0.2 g/l), and with subsequent changes to each of the other phenoxyalkanoates as a single substrate in the feed and with an intermittent return to 2,4-DP. Finally, after an intermediate substrate accumulation, 2,4-D, 2,4-DP, MCPA and MCPP could be degraded under the aforementioned conditions corresponding to a maximum degradation rate of Qphen = 100 mg/l × h. In the case of 2,4-DB, a slightly reduced conversion rate of about 94% could be calculated. In contrast to these results, 0.2 g/l of the more recalcitrant MCPB could not be metabolized at this high dilution rate of D = 0.5 h-1 by the biofilm of Sphingomonas herbicidovorans MH, but it was degradable at a reduced dilution rate of D = 0.25 h-1. Complete detoxification of a stoichiometric mixture of the dichloro- and the methylchloro-substituted phenoxyalkanoates including MCPB, respectively, at a total concentration of 0.2 g/l was achieved at D = 0.25 h-1, corresponding to a degradation rate of Qtot = 50 mg/l × h. Finally, the efficiency of the PU-immobilized cells of Sphingomonas herbicidovorans MH in detoxifying mixtures of all six herbicides could be increased to Qtot = 75 mg/l × h by the further addition of PU-foam particles corresponding to a final PU-load of 2.5% [w/v]. This PU-bubble reactor was successfully operated for more than 12 months to clean up synthetically concocted waste waters with fluctuations in phenoxyalkanoate concentration and composition.
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  • 39
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 307-318 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The biodesulphurization of Mengen lignite by a mesophilic bacterium, Rhodococcus rhodochrus ATCC 53968, was investigated in a batch stirred and aerated reactor. The experiments were carried out at 28°C with an inoculum percentage, initial pH, initial sodium acetate and lignite concentration of the biodesulphurization medium of 8% [v/v], 6.5 mM, 20 mM and 20 g/l, respectively. Variations in the sulphur contents of the lignite relative to the biodesulphurization period were monitored. The effects of the stirring and aeration rates on the removal of different sulphur forms from coal were investigated in the ranges 450-1,200 rpm and 0.1-0.53 vvm and the optimum values were found to be 500 rpm and 0.18 vvm, respectively. An increase in the total sulphur reduction with increasing biodesulphurization time was observed. The maximum total sulphur removal percentage was found to be 15.2% at 1,200 rpm after four days of incubation. The highest total sulphur removal rate was calculated on the second day of microbial desulphurization for each run. The total and organic sulphur contents of the coal after biodesulphurization were correlated with the stirring and aeration rates by using the non-linear least squares regression method. In the experimental runs lasting 8 days, the highest organic sulphur reducing percentage of 10.1% was obtained at a stirring rate of 500 rpm and an aeration rate of 0.40 vvm.
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  • 40
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Selected strains of basidiomycetes (Abortiporus biennis, Trametes versicolor and Cerrena unicolor) were shown to produce enhanced extracellular peroxidase (EP), superoxide dismutase (SOD) and laccase activities following the exposure of 10-day-old fungal cultures to separate high and low temperature stress. The stressful conditions also caused an increase in the concentrations of phenol compounds and superoxide anion radicals in these cultures. At first, peroxidase activity was observed at 12 hours from the moment of temperature stress application. Laccase activity appeared at 96 hours after the maximum levels of superoxide anion radicals (48 h) and SOD activity (36-72 h). The concentration of phenolic substances grew steadily during the period of cultivation. These relations between laccase, SOD and EP as well as superoxide radicals and phenol levels in the environment of ligninolytic fungi seems to be important in the course of the biosynthesis or biodegradation of lignin, as the consequence of adaptation of these basidiomycetes to environmental temperature conditions.
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  • 41
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 356-356 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 42
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 349-355 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Comamonas acidovorans MC1, which is capable of degrading the chiral phenoxypropionate herbicides 2-(2,4-dichlorophenoxy)propionate [dichlorprop, (RS)-2,4-DP] and 2-(4-chloro-2-methylphenoxy)propionate [mecoprop, (RS)-MCPP] and of degrading the phenoxyacetate herbicides 2,4-dichlorophenoxyacetate (2,4-D) and 4-chloro-2-methylphenoxyacetate (MCPA), was investigated with respect to the enzymatic basis of this broad substrate specificity. The initial steps of the degradation pathway of (RS)-2,4-DP and 2,4-D were studied. By applying either ion exchange chromatography or hydrophobic interaction chromatography it was possible to separate two enzyme fractions with etherolytic activity, which exhibited pronounced substrate specificity. One enzyme fraction was highly specific for the degradation of the R-enantiomer of 2,4-DP and did not essentially attack the S-configuration. The other enzyme fraction showed pronounced activity toward the cleavage of the S-enantiomer and additionally utilized 2,4-D with almost equal velocity; (R)-2,4-DP was even cleaved at a low rate by this enzyme. These results confirm the existence of phenoxyalkanoatedegrading enzymes with enantiospecific properties in strain MC1.
    Additional Material: 3 Ill.
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  • 43
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 44
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 191-203 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The population of poly-β-hydroxybutyrate-degrading microorganisms and the biodegradation of PHB in local landfill soils were examined in vitro and in vivo. Forty-two PHB-degraders consisting of 12 bacteria, 25 actinomycetes and 5 moulds were isolated. The total PHB-degraders averaged 4.7 × 107 and 20 × 104 colony forming units (cfu)/g for San Mateo wet and dry soils, respectively, and 2.3 × 107 and 8.5 × 104 cfu/g for Carmona wet and dry samples, respectively. The PHB-degraders formed 0-59% of the total microbial population in San Mateo and 8-42% in Carmona. Complete (100%) degradation of PHB powder was observed for Chryseomonas-27 and Aspergillus-39 on day 5 in shake flask culture and for Streptomyces-4 on day 7. Burial test in landfill soils showed a 90-91% weight loss of PHB film strips within four weeks; the weight loss of polypropylene film strips was up to 0.12% only. Scanning electron micrographs of degraded films revealed the attachment of microbial cells and fungal mycelium and spores on the surfaces. Holes and cavities were also noted due to the microbial degradation processes.
    Additional Material: 3 Ill.
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  • 45
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 205-210 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The application of biotechnology in environmental processes is an enormous subject that could remain the topic of a university lecture course for many years. For this reason I wish to limit my lecture to a few examples and to attempt to sketch out particularly promising opportunities for future development.
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  • 46
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 47
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 213-223 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Acinetobacter sp. E11, isolated from Port Dickson Beach, Malaysia, was able to grow in media containing crude oil as the sole carbon and energy source. Substrate specificity studies showed that the bacterium exhibited substrate preference as growth was observed only in media containing aliphatic hydrocarbons, while aromatic and cyclic hydrocarbons inhibited growth. With the aliphatic hydrocarbons, growth was seen only in the long-chain alkanes tested (pentadecane, dodecane and hexadecane). No growth was recorded in the short-chain alkanes (pentane, hexane and heptane) tested. With complex hydrocarbons, only crude oil and 4T SHELL engine oil supported growth. No growth was observed in kerosene and PETRONAS gasoline. The isolate could grow in up to 10% and 20% [v/v] of the crude oil and alkanes tested, respectively. Among the long-chain alkanes tested, hexadecane was the most preferred, followed by pentadecane and dodecane. Nitrogen and phosphorous supplements were essential for growth and the best growth was achieved with 3% nitrogen/phosphorous additions. Microscopic observation revealed that the bacterium adhered to the hexadecane and crude oil droplets. GC analysis showed that the bacterium was able to degrade more than 60% of the hydrocarbons in the crude oil in 15 days at 37°C compared to the uninoculated media.
    Additional Material: 3 Ill.
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  • 48
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 49
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 50
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 293-304 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mineralization of a non-ionic alcohol ethoxylate (AEO) surfactant was investigated over the concentration range occurring in rinsing water from surfactant production processes. For this, an experimental set-up for respirometric batch experiments was developed. The set-up and the method were validated by experiments with glucose as the single carbon source. It was possible to calculate substrate decay from the time course of exogenously consumed oxygen during respirometric batch experiments. The kinetic coefficients calculated by respirometry showed a lower standard deviation than those calculated from emasured glucose concentrations.The degradation mechanism of AEO was investigated by identification of metabolities, occurring during the mineralization process of AEO, using Flow Injection Mass spectrometry (FI-MS). It was concluded that the degradation of AEO occurs in two main steps. First, the enzymatic hydrolysis of AEO into alcohol and polythylene glycol (PEG) is performed. Second, the mineralization of both substances takes place, while the mineralization of the alcohol is faster than that of the PEG. The mineralization kinetics were investigated in respirometric batch experiments. The model used is based on double MONOD kinetics for the substrates being produced by hydrolysis (μmax1 = 0.047 h-1, Ks1 = 15 mg/l DOC for alcohol; μmax2 = 0.027 h-1, KS2 = 4 mg/l DOC for PEG). The validation of the model by calculating the results obtained from measurements in a continuously operated lab scale CSTR with bacteria recycle was successful.
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  • 51
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 69-75 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: An increase in the molar growth yield (YX/S = 14.3-20.3 g/mol) on glucose (25 mM) was achieved after the transition of Zymomonas mobilis ATCC 29191 from anaerobic to aerobic steady state growth at dilution rates of D = 0.31-0.40 1/h and under oxygen-unlimited conditions. The transfer of anaerobically or aerobically grown steady state cells into a fresh medium resulted in the higher values of YX/S. A positive correlation was established between biomass and acetaldehyde yield within the range of 5-9 mM acetaldehyde in the medium. An inhibitory effect of the exogenously added acetaldehyde (Ki = 16.7 ± 2.8 mM) on the ATPase activity was observed in vitro, using cell-free extracts of anaerobically grown Z. mobilis. The results obtained provide evidence that the increased values of biomass yield could be explained by the redirection of ATP usage during aerobic growth of Z. mobilis.
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  • 52
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 53
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 86-87 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 54
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999) 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 55
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 101-109 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pleurotus sajor-caju (FR.) SINGER was cultivated on different organic wastes, namely sericulture waste, Populus deltoides MARSH, and Eupatorium adenophorum SPRENG. Paddy straw was taken as the control and all the data were compared with it. The mineral contents of the fruiting bodies of Pleurotus sajor-caju and the substrates on which the mushroom was grown were analyzed. Among the eight minerals determined (calcium, phosphorus, potassium, magnesium, sodium, iron, manganese and zinc), the potassium content was highest followed by phosphorus, magnesium and sodium. Analysis of the mineral contents of the substrates before cultivation had also been carried out. The mineral contents of the fruiting bodies of Pleurotus sajor-caju were found to be different on different substrates. It was also observed that the mineral contents of the fruiting bodies of Pleurotus sajor-caju increase when cultivated on substrates with higher mineral contents. The maximum mineral contents per 100 g of the substrates before cultivation were Ca - 347 mg; P - 151 mg; K - 1,805 mg; Na - 127 mg; Mg - 227 mg; Fe - 53 mg; Mn - 10 mg and zn - 3.1 mg. The mineral contents of the fruiting bodies of Pleurotus sajor-caju per 100 g ranged as follows: Ca - 25.1 mg to 35.3 mg; P - 448 mg to 602 mg; K - 2,146 mg to 2350 mg; Na - 139 mg to 229 mg; Mg - 153 mg to 224 mg; Fe - 9.74 mg to 20.75 mg; Mn - 2.5 mg to 4.0 mg and Zn - 2.2 mg to 3.1 mg.
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  • 56
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    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 357-363 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: An alternative microbiological method for the production of malate from fumarate is presented. The yeast Dipodascus magnusii was used for this bioconversion.The optimum cell growth temperature was 28°C and the working volume 120 ml. The highest level of fumarase activity during bioconversion was achieved at a pH of 7.5 and a temperature of 37°C. These conditions were determined as optimal. Using sodium fumarate (1M), the maximum specific productivity of malic acid obtained was 1.72 g/(gDCW × h) for intact cells. In the case of ammonium fumarate, it was 2.25 g/(gDCW × h).
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  • 57
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    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 58
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 59
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 60
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
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  • 61
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 62
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 11-13 
    ISSN: 0009-2940
    Keywords: Triferriophosphane sulfide ; Metallothioxophosphorane ; PS complex ; Spiro compounds ; Decarbonylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The P-H-functional triferriophosphonium salts [{CpFe-(CO)2}3PH]2FeCl4 (1) and [{μ-CO(CpFeCO)2}{CpFe-(CO)2}PH]2FeCl4 (4) are easily deprotonated by DBU to the corresponding unstable triferriophosphanes 2, 5, which subsequently are oxidized by sulfur to the triferriophosphane sulfides {CpFe(CO)2}3P=S (3) and {μ-CO(CpFeCO)2}{CpFe-(CO)2}P=S (6), respectively. The photolysis of 3 results only in its decomposition by elimination of [CpFe(CO)2]2, whereas the photolysis of 6 cleaves off one CO ligand to give the new spiro compound (CpFeCO)(μ-η2-PS){μ-CO(CpFeCO)2} (7), where the P=S unit is η2-bonded to the 15-electron CpFeCO fragment, and the phosphorus atom bridges two 17-electron fragments. Compound 7 shows a new coordination mode of the PS unit where sulfur is also bound to one of the metal atoms. Compounds 6 and 7 can be regarded as first examples of a new class of PS complexes of transition metals. All compounds were characterized by IR, 31P{1H}- and 13C{1H}-NMR spectroscopy as well as mass spectrometry; for 6 the X-ray analytical data are given.
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  • 63
    ISSN: 0009-2940
    Keywords: Triazacyclohexanes ; Chromium complexes ; Amides ; Hexamethyldisilane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of N,N′,N′′-trimethyl-1,3,5-triazacyclohexane chromium trichloride ((Me3TAC)CrCl3, 1) with LiN(SiMe3)2 or NaN(SiMe3)2 in petroleum ether yields nearly quantitatively [Cr{N(SiMe3)2}3] (2) with loss of the Me3TAC ligand. Compound 2 could be crystallized from hexamethyldisilane as [Cr{N(SiMe3)2}3] · (Me6Si2)0,5 which allowed the refinement of the X-ray crystal structure in the trigonal space group P-31c (no. 163) (a = 16.012(3) Å, c = 8.4796(12) Å, V = 1882.8(6) Å3, Z = 2) without severe disorder.
    Additional Material: 3 Ill.
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  • 64
    ISSN: 0009-2940
    Keywords: Glyceraldehyde ; Ligands, tridentate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of seven chiral, tripodal N,O,S and N,N,O ligands were prepared in which N stands for a secondary amine or imidazole donor, O for a phenol, and S for a thioether or thiol metal-binding group. Key steps are (1) the construction of ortho-hydroxyacetophenones bearing the phenolic binding group and either a thioether, a protected thiol or an imidazole substituent in the α-position, and (2) subsequent reductive amination with a primary amine. The modular synthesis allows a rapid construction of a variety of structurally related ligands. In three cases, the enantiomers of the racemic products could be separated after condensation with (R)-glyceraldehyde acetonide as chiral auxiliary. The relative configurations of the cyclic N,O- and N,N-acetals thus obtained were established by NOE spectroscopy. X-ray structural analysis of two crystalline N,O- and N,N-acetals allowed the assignment of absolute configurations. Hydrolysis of the dia-stereomerically pure acetals afforded the enantiomerically pure ligands in high yield. By comparison of their CD spectra, absolute configuration could also be assigned to the third pair of enantiomerically pure ligands.
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  • 65
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 85-89 
    ISSN: 0009-2940
    Keywords: Rhodium complexes, chiral ; Hydrogenation ; Bisolefins ; Thermodynamic stability ; Kinetic control ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Asymmetric hydrogenations of prochiral olefines by means of chiral rhodium(I) complexes of the type [Rh(L)(PP*)]A (L = COD, [(Z,Z)-cycloocta-1,5-diene], or NBD (norborna-2;5-diene), PP* = chiral bisphosphane forming seven-membered chelate rings, A = anion like BF4-) are often associated with induction periods caused by partial blocking of the catalyst. NBD complexes are hydrogenated faster than the corresponding COD complexes. Catalytic hydrogenation of COD/NBD mixtures and the determination of the ratio of the Michaelis constants showed that the steady-state concentration of the COD complex under hydrogen is higher than that of the NBD complex. However, under argon the NBD complex predominates owing to its higher thermodynamic stability compared with that of the COD complex as determined by 31P-NMR spectoscopy. This complete reversion of the ther-modynamically determined ratios of COD to NBD complex concentration under hydrogenation conditions was proven by means of UV/Vis spectroscopy.
    Additional Material: 5 Ill.
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 233-235 
    ISSN: 0009-2940
    Keywords: Positional selectivity ; Bromination ; Halogen/lithium exchange ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Bromo-3,5-bis(trifluoromethyl)benzene (1) can be selectively prepared by treatment of 1,3-bis(fluoromethyl)benzene with N,N'-dibromo-5,5-dimethylhydantoin in strongly acidic media. A number of synthetically useful reactions via 3,5-bis(trifluoromethyl)phenylmagnesium, -lithium, and -copper intermediates were accomplished.
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  • 67
    Electronic Resource
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 253-257 
    ISSN: 0009-2940
    Keywords: Lithiated phosphane imines ; Phosphane imines, lithiated ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lithiated Phosphane Imines. Synthesis and Crystal Structures of [LiCH2PMe2NSiMe3]4 and [LiCMe2P(iPr)2NSiMe3]2The title compounds were prepared by the reaction of Me3-SiNPMe3 and Me3SiNP(iPr)3, respectively, with n-Butylli-thium at 20°C in n-hexane solution. They form white, moisture- and oxygen-sensitive crystals, which were characterized by IR spectroscopy and by crystal structure determinations. - [LiCH2PMe2NSiMe3]4 (1) forms a Li4 tetrahedron, the faces of which are capped with CH2 groups with average Li-C distances of 233 and 251 pm, while the nitrogen atoms occupy the corners of the Li4 tetrahedron. - [LiCMe2P(iPr)2N-SiMe3]2 (2) forms molecules of symmetry C2 in which the lithium atoms have coordination number three by two carbon atoms and one nitrogen atom with Li-C distances of 215.2 and 237.9 pm and Li-N of 192.8 pm.
    Additional Material: 5 Ill.
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  • 68
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 269-273 
    ISSN: 0009-2940
    Keywords: Organometallic polymers ; Coupling reactions ; Butadiynyl complexes ; Cobalt compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of 3a starting from compound 1 is described. Copper-catalyzed oxidative coupling of 3b under Hay conditions gives the novel polymer 9 with octatetrayne-cyclobutadiene units.
    Additional Material: 4 Ill.
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  • 69
    ISSN: 0009-2940
    Keywords: Bis[2.2]metacyclophanes ; Stilbenes ; π-π Interaction ; Tricarbonylchromium complexes ; Charge-transfer ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (E)-8,8′-(Ethene-1,2-diyl)bis(5-tert-butyl[2.2]metacyclo-phane) (2) was obtained from a McMurry reaction of 5-tert-butyl-8-formyl[2.2]metacyclophane (1). Irradiation of 2 with a high-pressure mercury lamp gave the corresponding (Z) isomer 3. X-ray crystallographic analyses of 2 and 3 show a certain degree of twisting of the bond connecting the meta-cyclophane unit and the central π system due to steric crowding. UV spectra of 2 and 3 and of the charge-transfer complexes [2/TCNE] and [3/TCNE] allow for a discussion of π-π interaction between the central stilbene subunit and the outer benzene rings of the metacyclophane units. Bis[2.2]meta-cyclophanes 2 and 3 reacted regioselectively with hexacar-bonylchromium on the outer benzene rings giving 1:1 and 1:2 complexes 9-14 with tricarbonylchromium. No 1:3 and 1:4 complexes formed due to steric restrictions. Analysis of UV spectral data of the complexed [2.2]metacyclophanes was performed for an indication of π-π interactions in the complexes.
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  • 70
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 283-287 
    ISSN: 0009-2940
    Keywords: Self-assembling frameworks ; Thermal stability ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Here we report on investigations that have revealed for the first time that the Cs+ ion templates the same metal germanium sulfide open-framework as (CH3)4N+ (TMA+), and that metal complexing agents enhance crystal size by at least two orders of magnitude. The synthesis, structures and thermal properties of Cs2FeGe4S10 ·× H2O and TMA2FeGe4S10 are also described. Both have 3D zinc blende-type open-framework structures. These materials have the same connectivity as TMA2MnGe4S10. The tetrahedral sites in the lattice are alternately substituted by pseudo-tetrahedral Fe2+ and adamantanoid Ge4S104- building blocks, covalently linked together by Fe(μ-S)Ge bridge bonds, to give a tetragonal unit cell. The charge-balance of the anionic framework [Fe-Ge4S10]2- is maintained by either Cs+ or TMA+ ions in the cavity spaces. Synthesis of these materials demonstrates an interesting example of a self-assembly process in which a 3D framework is built from molecular precursors. Water adsorption-desorption cycling from room temperature to 200 °C reveals framework flexibility between larger and smaller tetragonal unit cell 14 isotypes. The compound TMA2FeGe4S10 is stable in nitrogen at 350 °C and under vacuum at 450 °C. The corresponding temperatures for Cs2FeGe4S10 are 530 °C and 630°C; it is stable on cooling to room temperature under vacuum, and after subsequent exposure to air. Six hundred thirty degrees celsius is the highest recorded temperature at which the integrity of a non-oxide framework has been maintained. The framework stability and flexibility of “all-inorganic” Cs2FeGe4S10 provides an encouraging example for researchers interested in developing sulfide-based framework materials with practical applications.
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  • 71
    ISSN: 0009-2940
    Keywords: Gold complexes ; Silver complexes ; Palladium complexes ; S-Donor ; Thiones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: AgClO4 reacts with bidentate ligands 2-(methylthio)pyridine (SMepy) or complexes PPN[Au(Spy)2] [PPN = N(PPh3)2, HSpy = pyridine-2(1H)-thione) or PPN[Au(Sbz)2] (HSbz = benzoxazole-2(3H)-thione), themselves acting as ligands, to give dinuclear complexes [Ag2(μ-SMepy)2](ClO4)2 (1), [AgAu(μ-Spy)2] (2), or [AgAu(μ-Sbz)2] (3), respectively. By treating 1 with [AuCl(tht)] (tht = tetrahydrothiophene), [Au(SMepy)(tht)]ClO4 (4) is obtained which, in turn, reacts with SMepy to give [Au(SMepy)2]ClO4 (5). Similarly, [PdCl2(NCPh)2] reacts with SMepy in 1:1 molar ratio to give [Pd2Cl2(μ-Cl)2(SMepy)2] (6) which reacts with SMepy in 1:2 molar ratio to give [PdCl2(SMepy)2] (7). On the other hand, HSpy reacts with Ag2CO3 to give [Ag2(μ-Spy)2] (8), and (SMepyH)ClO4 reacts with [Au(acac)PPh3] (acacH = acetyl-acetone) to give [Au(SMepy)PPh3]ClO4 (9).
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  • 72
    ISSN: 0009-2940
    Keywords: Histidine peptides ; Zinc complexes ; EXAFS analysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: One tripeptide, five tetrapeptides, and one pentapeptide, all containing His-Xn-His sequences and being blocked at the N and C termini with acyl and amide functions, respectively, were synthesized by solid-phase methods. With one exception their reaction with various zinc salts led to the precipitation of 1:1 (zinc/peptide) complexes. Analytically pure compounds were obtained from zinc tetrafluoroborate and His-Gly-His (1), from zinc chloride (resp. bromide) and His-Gly -Gly-His (2), His-Ala-Gly-His (3), His-Leu-Gly-His (4), His-Pro-Gly-His (5), and His-Pro-Asn-His (6) as well as from zinc sulfate and His-Leu-Gly-His (4) and His-Ala-Pro-Gly-His (7). 1H-NMR data, when available, indicate the coordination of both histidine units to zinc in all cases. The low solubility of the complexes points to their polymeric nature. The only 1:2 (zinc/peptide) complex in this series was obtained from zinc perchlorate and His-Gly-Gly-His (2). An EXAFS study revealed that it contains zinc symmetrically coordinated by four histidine imidazole ligands. Based on the available information it is proposed that all complexes are one-dimensional polymers containg [-Zn-His-Xn-His-Zn-]x backbones.
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  • 73
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    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 74
    ISSN: 0009-2940
    Keywords: Silanediols ; Silanetriols ; Siloxanes ; Hydrogen bonding ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The silanediols RN(SiMe3)Si(OSiMe3)(OH)2 (R = 2,4,6-Me3C6H2 4, 2,6-Me2C6H3 5, and 2,6-iPr2C6H3 6) were prepared by the reactions of the respective silanetriols RN(SiMe3)-Si(OH)3 1 - 3 with SiMe3Cl in THF/hexane. Silanetriol 1 in CH2Cl2/hexane solution converts over a period of 4 weeks into the silanediol (2,4,6-Me3C6H2)N(SiMe3)Si(OSiMe2 R)-(OH)2 [R = CH2(2-NH2-3,5-Me2C6H2)] (7). Compounds 4 - 7 were characterized by means of mass, IR and NMR (1H and 29Si) spectroscopy. Additionally, the molecular structures of 4 and 7 were determined by single-crystal X-ray diffraction studies. Compound 4 forms O — H…O hydrogen-bonded tetramers in the solid state. A nine-membered ring formed by an intermolecular O—H…N hydrogen bond is found in the solid-state structure of 7.
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  • 75
    ISSN: 0009-2940
    Keywords: Iridium complexes ; Stibane complexes ; Hydrido complexes ; Ethene complexes ; Ligand displacement reactions ; Alkyne-to-vinylidene rearrangement ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of [IrCl(C8H14)2]2 (2) with SbiPr3 in the presence of H2 yields the dihydridoiridium(III) complex cis,mer-[IrH2Cl(SbiPr3)3] (3) which on treatment with CO and with HC≡CR (R = Ph, CO2Me) affords the octahedral derivatives [IrH2Cl(CO)(SbiPr3)2] (4) and [IrHCl(C≡CR)(SbiPr3)3] (5, 6), respectively. The stibane ligand trans to hydride in 5 and 6 is rather labile and, therefore, 5 and 6 react with pyridine to give [IrHCl(C≡CR)(py)(SbiPr3)2] (7, 8). Five-coordinate bis-(stibane)iridium(I) complexes [IrCl(C2H4)2(SbR3)2] (10-12) were prepared from [IrCl(C2H4)2]2 (9) and four equiv. of SbR3 (R = iPr, Me, Ph). The X-ray crystal structural analysis of 10 reveals a distorted trigonal-bipyramidal geometry around the metal center with one stibane ligand and the two olefinic ligands in the equatorial plane. Compound 10 reacts with NaC5H5 to yield [C5H5Ir(C2H4)(SbiPr3)] (13) and with different alkynes by partial or complete displacement of the ethene ligands to give trans-[IrCl(PhC≡CPh)(SbiPr3)2] (14), [IrHCl(C≡CTol)(C2H4)(SbiPr3)2] (15), and trans-[IrCl-{=C=C(SiMe3)R}(SbiPr3)2] (16, 17), respectively.
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  • 76
    ISSN: 0009-2940
    Keywords: Azolylborane adducts ; Boron-imidazole adducts ; Boron-pyridine adducts ; Protic-hydric interactions ; Protic-fluoride interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation, NMR and X-ray diffraction studies of a series of azolylboron hydrides derived from pyrrole, indole, and carbazole coordinated with tetrahydrofuran, pyridine, and imidazole are reported. The azolyl substituents are very electroattractive leading to an acidic boron atom which strongly coordinates with the Lewis bases. The stabilization of the =BH2=groups against disproportionation could be explained in terms of the interactions found between the acidic hydrogen atoms of the heterocycles (C=Hδ+ acceptor) and the hydrides (B=Hδ- donors).
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  • 77
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 78
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 485-487 
    ISSN: 0009-2940
    Keywords: Dimetallations ; Insertions ; Rhenium ; Isothiocyanates ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecules containing dimetallated hydrocarbyl groupings are of great chemical interest[1-3]. These groupings often represent intermediates in important catalytic processes[4]. Recently, we have shown that substituted dimetallated olefins can be formed by alkyne insertion into the metal-metal bonds of certain dinuclear complexes[2,5]. Complexes having dimetallated hydrocarbyl groups combined with heteroatoms are quite rare[6]. Herein is described the formation of a dimetallathioimidate grouping by the insertion of an organic isothiocyanates into an unsupported metal-metal bond. Organic isothiocyanates are useful reagents in organic synthesis[7], but the organometallic chemistry of these molecules is not yet well developed[8].
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  • 79
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 521-525 
    ISSN: 0009-2940
    Keywords: Liquid crystals ; Siloxanes ; Phase behaviors ; Defined topology ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that supermolecules with a tetrahedral symmetry and appropriate side-chains exhibit liquid-crystalline phase behaviour. The use of an optimised hydrosylation reaction allows for the synthesis of materials that have four mesogenic groups attached to a siloxane core, where the conformation and the configuration are unambiguous. The materials show low glass transition temperatures and, depending on the spacer length, complex liquid-crystalline morphologies.
    Additional Material: 3 Ill.
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  • 80
    ISSN: 0009-2940
    Keywords: Iron and ruthenium complexes ; Water soluble complexes ; Sulfur ligands ; X-ray structure analyses ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In search of water soluble transition metal complexes with sulfur dominated coordination spheres that model key reactions of nitrogenases, the benzenedithiol derivatives ‘CO2HS2’-H2 (1) and ‘CO2Me-S2’-H2 (2) were synthesized as precursors for multidentate sulfur ligands. The template alkylation of 2 by C2H4Br2 at [Fe(CO)2] fragments yielded a mixture of two diastereomeric C2 symmetrical [Fe(CO)2(‘CO2Me-S4’)] complexes (4a and 4b), which were separated by crystallization. The hydrolysis of the mixture of the diastereomers 4a and 4b led to the isomerically pure tetradentate thioether thiol ligand ‘CO2Me-S4’-H2 (5) proving the regioselectivity of the template alkylation of the asymmetrical dithiol 2. The C1 symmetrical [Fe(‘CO2Me-S2’)2]2- anion is an intermediate of the template alkylation and was isolated as (AsPh4)2 [Fe(‘CO2Me-S2’2] (11), 4a, 5 and 11 were characterized by X-ray structural analysis. Saponification of the methyl ester groups of 5 yielded ‘CO2H-S4’-H2 (7). Treatment of 7 with FeCl2 · 4 H2O in the presence of CO and LiOMe gave a mixture of two C2 symmetrical and water soluble diastereomers of Li2[Fe(CO)2(‘CO2-S4’)] (8). Upon treatment with [RuCl2 (PPh3)3] 7 yielded isomerically pure [Ru(PPh3)2-(‘CO2H-S4’)] (9). 9 also exhibits C2 symmetry and could be reversibly deprotonated to form the water soluble complex K2[Ru(PPh3)2 (‘CO2-S4’)] (10). Treatment of (NBu4)2 (‘CO2MeS2’) with “Ru(NO)Cl3” led to isomerically pure (NBu4)[Ru(NO)(‘CO2Me-S2’)2] (12).
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 833-836 
    ISSN: 0009-2940
    Keywords: Oxotitanium(IV) porphyrinate ; Peroxotitanium(IV) porphyrinate ; Photochemistry ; Singlet oxygen ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The syntheses of oxotitanium(IV) meso-tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrinate O=Ti(TPPF20) (1), oxotitanium(IV) meso-tetrakis(2,6-difluorophenyl)porphyrinate O=Ti-(TPPF8) (3), and oxotitanium(IV) meso-tetrakis(2,6-dichlorophenyl)porphyrinate O=Ti(TPPCl8) (5) from titanium tetrachloride and the corresponding porphine are described. The structure of 1 was determined by single-crystal X-ray diffraction. The reaction of oxotitanium porphyrinates with aqueous hydrogen peroxide leads to the corresponding light-sensitive peroxotitanium(IV) complexes: Ti(O2)(TPPF20) (2), Ti(O2)-(TPPF8) (4), Ti(O2)(TPPCl8) (6). All complexes are efficient and stable photosensitizers for the generation of singlet oxygen.
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  • 82
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 837-839 
    ISSN: 0009-2940
    Keywords: Boron compounds ; Silaboranes ; Dihetero-closo-borane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of 3 equivalents of KH · BEt3 to [Me3NH][Me-SiB10H12] followed by addition of one equivalent of SnCl2 or SbI3 affords the stanna-sila-closo-borate(1-) 3 and stiba-sila-closo-borane 4, respectively. [MePh3P] · 3 crystallizes in the orthorhombic space group P212121.
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  • 83
    ISSN: 0009-2940
    Keywords: Amides ; Pyrrolyl complexes ; Chelate complexes ; Transition-metal complexes ; Metallacycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Intramolecularly Stabilized Metal Amides: 2-(Dimethylaminomethyl)pyrrolyl Complexes of Titanium(III), Vanadium(III), Chromium(III), Cobalt(II) and Nickel(II)By the metallation of 2-(dimethylaminomethyl)pyrrol (HL) with butyllithium the lithium pyrrolide LiL (1) was obtained. The reactions of 1 with TiBr3 · 3 THF, VBr3 · 3 THF, CrBr3 · 3 THF, CoBr2 · 2 THF, and NiBr2 · 1.67 THF result in the formation of the 2-(dimethylaminomethyl)pyrrolyl complexes of type ML3 (2-4), and ML2 (5, 6), respectively. The structures of these new compounds are discussed on the basis of magnetic and visible absorption measurements. An X-ray crystal structure determination of 4 reveals a strongly distorted octahedral environment of the chromium atom with facial arrangement of the ligands.
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  • 84
    ISSN: 0009-2940
    Keywords: Rhodium complexes ; Alkyne complexes ; Insertion reactions ; Alkyl isocyanides ; Metallacycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cyclopentadienyl complexes [C5H5Rh(RC≡CR′)(SbiPr3)] (5-8), which were prepared from trans-[RhCl-(RC≡CR′)(SbiPr3)2] (1-4) and NaC5H5 and which contain a labile Rh-SbiPr3 bond, reacted with CO and CNR″ (R″ = Me, tBu) to give the carbonyl and isocyanide derivatives [C5H5Rh(RC≡CR′)(CO)] (9-11) and [C5H5Rh(RC≡CR′)-(CNR″)] (12-16), respectively. On treatment of 12 (R = R′ = Ph; R″ = Me) with SbiPr3, the metallacyclobutene complex [C5H5Rh{κ2(C,C}-C( = NMe)CPh=CPh}(SbiPr3)] (17) was formed; it reacts with excess CNMe or CNtBu to yield the metallacyclopentenes [C5H5Rh{κ2(C,C)-C(=NMe)CPh=CPhC-(=NR)}(CNR)] (18, 19). Similar compounds 20-23 containing a five-membered RhC4 metallacycle were prepared either from [C5H5Rh(RC≡CR′)(SbiPr3)] (7, 8) or [C5H5Rh-(PhC≡CPh)(CNtBu)] (14) and excess isocyanide. The crystal and molecular structures of 17 and 18 (R = Me) have been determined.
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  • 85
    ISSN: 0009-2940
    Keywords: Phthalocyanines ; Porphyrins ; Lanthanide(III) compounds ; Macrocyclic ligands ; Double-decker complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of 5,10,15,20-tetra-4-pyridylporphyrin [(TPyP)H2] with europium(III) or gadolinium(III) acetylacetonate [Ln(acac)3 · nH2O] (Ln = Eu, Gd) in 1,2,4-trichlorobenzene produced Ln(acac)(TPyP), which reacted with dilithium phthalocyaninate [Li2(Pc)] to give Li[Ln(Pc)(TPyP)] in moderate yields. Upon exposure to air, solutions of these compounds converted slowly to the corresponding neutral complexes Ln(Pc)(TPyP). The new compounds were spectroscopically characterized.
    Additional Material: 2 Ill.
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 937-944 
    ISSN: 0009-2940
    Keywords: Iron acyl complexes ; (Alkynyl)carbene ligand ; Cationic aminocarbene complexes ; Iron (2-methoxyvinyl)aminocarbene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: (Alkynoyl)iron complexes 1, Cp(CO)2Fe(O=CC≡CR) (R = CH3, Ph, SiMe3), were synthesized by applying a mixed anhydride procedure and transformed into the cationic methoxycarbene complexes 2, [Cp(CO)2 Fe(C(OMe)C≡CR)+]-[PF6-]. Primary amines H2NR′ react with the methoxycarbene complexes to furnish exclusively cationic aminocarbene complexes 3, [Cp(CO)2 Fe(C(NHR′)C≡CR)+][PF6-], or (2-methoxyvinyl)aminocarbene complexes 5. The spectroscopic properties of the new complexes are discussed. The (alkynyl)-aminocarbene complexes 3e and 3f were characterized by X-ray crystal structure analysis.
    Additional Material: 2 Ill.
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  • 87
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 967-971 
    ISSN: 0009-2940
    Keywords: Phthalocyanines, sulphonated ; Diazadithiamacrocycles ; Pentanuclear complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal phthalocyanines (M = Cu, Ni, Co) 3-5 bearing four 16-membered diazadithia macrocycles at the peripheral positions were prepared. Detosylation with concentrated sulfuric acid afforded products containing both sulfonated groups on the aromatic rings of the macrocyclic substituents which are excellently soluble in water and donor sites for binding four CuII ions to give a pentanuclear complex.
    Additional Material: 2 Tab.
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  • 88
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1379-1381 
    ISSN: 0009-2940
    Keywords: Thionitrosyl chloride ; Thiazyl chloride ; Neutralization-reionization mass spectrometry ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ab initio MO calculations at the QCISD(T)/6-311++G(3df,2p) + ZPE level show that the thionitrosyl chloride ion, ClNS+•, is 36 kJ/mol more stable than the thiazyl chloride ion, NSCl+•, whereas neutral NSCl is 77 kJ/mol more stable than ClNS [IEa (ClNS) = 9.2 ± 0.3 eV, IEa (NSCl) = 10.5 ± 0.3 eV]. Mild flash-vacuum pyrolysis of the thiazyl chloride trimer (NSCl)3 followed by electron impact ionization resulted in the formation of [N,S,Cl]+• ions (m/z 81). The fragments observed in the CA spectrum of these ions indicate the formation of both NSCl+• and ClNS+• ions. A very weak recovery signal is observed in a neutralizationreionization experiment. This signal is tentatively assigned to the neutral thionitrosyl chloride.
    Additional Material: 4 Ill.
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  • 89
    ISSN: 0009-2940
    Keywords: Gold ; Mercury ; Nitroaryl ; Transmetallation ; Biaryl ; C-C Coupling ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-Butoxynitrobenzene reacts with [Hg(O2CCF3)2] and LiCl to give [Hg(R)Cl] [R = C6H3NO2-3, OnBu-6 (1)] which is symmetrized by Me4NCl to give [HgR2] (2), the crystal structure of which has been determined. The reaction of 2 with Me4N[AuCl4] affords Me4N[Au(R)Cl3] (3) by a facile transmetallation process. Complex 3 reacts with PPh3 (1:1) to give cis-[Au(R)(PPh3)Cl2] (4). The diaryl complex [-Ph-2)(R)Cl] (5) is obtained by reaction of 3 with [Hg-(C6H4N=NPh-2)2] through a second transmetallation reaction. Complex 5 and PPh3 (1:1) give [AuClPPh3] and the C-C coupling biphenyl RC6H4N=NPh-2 (6).
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  • 90
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1409-1419 
    ISSN: 0009-2940
    Keywords: Sulfenic acid anions ; Thiosulfinic acid anions ; Thiosulfonic acid anions ; Transition metal complexes ; Stereochemistry ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and coordination chemistry of sulfenic, thiosulfinic, and thiosulfonic acid anions are reviewed. Different approaches, which yield the platinum(II) and ruthenium(II) complexes containing the anionic sulfur(0), sulfur(II), and sulfur(IV) oxid ligands, are described. The oxidative addition of thiosulfinates or N-sulfinyl phthalimides to platinum(0) complexes L2Pt(C2H4) [L = PPh3, 1/2 PPh2CH2CH2PPh2, 1/2 (R,R)-(-)-DIOP, 1/2 (C5H4PPh2)Fe(C5H4PPh2) leads to sulfenato complexes; those of N-thiosulfinyl phthalimidies or trisulfid 1-oxides afford the thiosulfinato complexes. Moreover, the reactions of CpRu(PPh3)(L)(SH) (L = CO, PPh3) with N-sulfinyl phthalimides forming the thiosulfinato moiety, are reported. The spectroscopic, structural and chemical properties of these complexes are discussed.
    Additional Material: 5 Ill.
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  • 91
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1057-1059 
    ISSN: 0009-2940
    Keywords: (Alkynyl)carbene ligands ; Iron acyl complexes ; Cationic iron aminocarbene complexes ; Diels-Alder reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic iron (alkynyl)aminocarbene complexes [Cp(CO)2Fe(C(NHR)C≡CSiMe3][PF6], (R = C6H5, p-CH3C6H4) 1 derived from aromatic amines smoothly react with cyclopentadiene in dichloromethane to yield the cycloadducts 2. No reaction was observed for complexes derived from sterically demanding aliphatic amines, like L-alanine tert-butyl ester. For comparison, the alkynyl-substituted acyl iron compounds Cp(CO)2Fe(C=O)C≡C̊ (R = SiMe3, C6H5) 3 were investigated, requiring TiCl4 catalysis to undergo the cycloaddition reaction. The structures of the cycloadducts 4 were determined by X-ray crystallography.
    Additional Material: 1 Ill.
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  • 92
    ISSN: 0009-2940
    Keywords: Nickel(0) ; Alkyne complexes ; Hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of (cdt)Ni (cdt: cyclododeca-1,5,9-triene) with 2 equivalents of 2-methyl-4-trimethylsilyl-3-butyn-2-ol leads to the selective formation of the homoleptic complex (alkyne)4Ni3 (compound 3), which can be isolated in excellent yields. The solid-state structure of 3 exhibits three Ni centers, forming a bent Ni3 chain connected by two bridging alkynes. The other two alkynes are terminally coordinated. Additionally, the trimeric units are stabilized by three intramolecular hydrogen bonds. Two intermolecular hydrogen bonds connect the trimeric units to form a polymer rope. According to the 13C- and 1H-NMR spectra in THF the structure of the complex 3 in solution is very similar to that in the solid state. The reaction of 3 with some alkynediols and with 2,5,5-trimethylhex-3-yn-2-ol affords compounds of the type (alkyne)2Ni. Cot (cot: 1,3,5,7-cyclooctatetraene) converts 3 into [(cot)Ni]2, which in turn reacts with 2,5-dimethylhex-3-yne-2,5-diol to form the dimeric complex (alkyne)2Ni2(cot) 6. X-ray analysis of 6 reveals a very symmetrical structure in which cot connects both Ni(0) centers at opposite sides of the ring system.
    Additional Material: 4 Ill.
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  • 93
    ISSN: 0009-2940
    Keywords: Sulfur dioxide ; Rhodium complexes ; Ether-phosphanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The SO2 coordination mode at the rhodium complex [ClRh(P∼O)()] (1) [ = η2(O,P)-chelated Cy2PCH2CH2OCH3 ligand; P∼O = =1(P)-coordinated] is controlled by the hemilabile ligand Cy2PCH2CH2OCH3 and shows a dependence on the polarity of the solvent. In polar organic solvents (e.g. acetone) the addition of sulfur dioxide results in the formation of a trigonal-pyramidal oriented SO2 group in [ClRh(η1-SO2)(P∼O)()] (2a). However, in nonpolar media (e.g. n-hexane) a trigonal-coplanar geometry of the SO2 unit in [ClRh(η1-SO2)(P∼O)2] (2b) is favored.
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  • 94
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 95
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1475-1482 
    ISSN: 0009-2940
    Keywords: Allenylidene complexes ; Alkynyl complexes ; Cyclobutenylidene complexes ; Cycloadditions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pentacarbonyl(allenylidene)chromium and -tungsten, [(CO)5—M=C=C=CR2] (M=Cr, R=C6H4CH3-p(1a), C6H4OCH3 (1b); M=W, R=C6H4CH3-p (1c), react with the alkynyl complexes [Cp(CO)2Fe—C≡CR′] (R′ = nBu (2), Ph (4)), [Cp*(CO)2Fe—C≡CnBu] (6), [Cp(CO){P(OMe)3}-Fe—C≡CnBu] (8) and [Cp(PPh3)Ni—C≡CnBu] (10) by cycloaddition of the C≡C bond of the alkynyl complexes to the Cα=Cβ bond of the allenylidene ligand to give 3a-c), (5), (7), and respectively. The cycloaddition is highly selective. The spectroscopic data of these 1,3-heterobinuclear complexes indicate a delocalized π-system (M=Cr, W; Y=[Fe(CO)2Cp], [Fe(CO)(P{OMe}3)Cp], [Fe(CO)2Cp*], [Ni(PPh3)-Cp]). X-ray structural analyses of the compounds 3a, 9a, and 11c reveal a “butterfly” conformation of the four-membered ring. Its puckering angle is 142° (3a), 152° (9a), and 151° (11c). All Complexes exhibit a moderate to strong negative solvatochromic behavior. The extent of the solvatochromic effect depends on [(CO)5M] and Y and considerably decreases when C=CR2 is replaced by e.g. CMe2.
    Additional Material: 3 Ill.
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  • 96
    ISSN: 0009-2940
    Keywords: Phosphate - Phosphonate rearrangement ; Carbanions, benzylic, configurational stability of ; α-Hydroxyphosphonates, tertiary, chiral, non-racemic ; t-Butyl(phenyl)phosphinothioic acid, homochiral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optically active alcohols (ee ≥ 98%) such as 1-phenylpropanol, 1-(2-naphthyl)ethanol, 1-tetralol, and 1-indanol were transformed into diethyl phosphates 7a-d. sBuLi/TMEDA  -  induced phosphate - phosphonate rearrangement in diethyl ether furnished tertiary α-hydroxyphosphonates 8a-d of high enantiomeric purity (ee 94-98%) in yields of 43-83% with retention of configuration. The enantiomeric excesses were determined by using homochiral t-butyl(phenyl)phosphinothioic acid as chiral solvating agent.
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  • 97
    ISSN: 0009-2940
    Keywords: 1,1-Dithiolate ; Manganese complexes ; Rhenium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The cationic tetracarbonyl complex cis-[Mn(CO)4-(S2CPCy3)]+ undergoes addition of hydride ion to the central carbon of the S2CPR3 ligand to afford, after spontaneous dimerization with loss of CO, the dimer [Mn2(CO)6{μ-S2C(H)PCy3}2] (5a), which was characterized by analytical and spectroscopic methods as well as by X-ray diffraction. In the molecule of 5a each S2C(H)PCy3- ligand is coordinated to one manganese in an η2-S,S′ chelate fashion, and one sulfur of each ligand serves as a bridge to bind the other manganese atom, thus forming a distorted Mn2S2 square. This appears to be a very stable arrangement. Compound 5a can be more easily prepared by treating the perchlorato complex [Mn(CO)3(S2CPCy3)(OClO3)] (2a) with NaBH4. This procedure is general and can be used for the preparation of several derivatives containing either manganese or rhenium [M2(CO)6{μ-S2C(H)PR3}2] 5a-d. The reaction of cationic tricarbonyl complexes [M(CO)3(S2CPR3)(PPh3)]PF6 (M = Mn, Re) with NaBH4 produced the same dimers 5a or 5c by displacement of the PPh3 ligand. Treatment of the dimer 5a with excess PEt3 or P(OMe)3 leads to the cleavage of the bridges and loss of one CO and the PR3 group from the S2C(H)PR3 unit to afford ultimately the dithioformate complexes [Mn(CO)2(S2CH)(L)2] [L = PEt3, P(OMe)3].
    Additional Material: 1 Ill.
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  • 98
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1621-1625 
    ISSN: 0009-2940
    Keywords: Organo-zinc compounds ; Phosphaneiminato complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organo-Zinc Phosphaneiminato Complexes with Heterocubane StructureThe organo-zinc heterocubanes [ZnR(NPMe3)]4 with R = CH3 (1) and n-C4H9 (2) were prepared by the reaction of [ZnBr(NPMe3)]4 with MeLi and nBuLi, respectively, in hexane solution. In a similar reaction of nBuLi with [ZnI(NPMe3]4 the phosphaneiminato complex [Zn4I(nBu)4(NPMe3)3] (3) is formed. 1-3 were characterized by IR, NMR and MS spectroscopy, and by crystal-structure determinations. 1 and 2 possess heterocubane structures in which the zinc atoms are linked via μ3-N bridges of the phosphaneiminato groups, and all bond angles in the Zn4N4 core are close to 90°. A distorted heterocubane structure is observed for 3 with one of the NPMe3 moieties replaced by an iodine atom.
    Additional Material: 3 Ill.
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  • 99
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    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 161-167 
    ISSN: 0009-2940
    Keywords: Sulfoxonium ylides ; 1,3-Dithietane 1,1,3,3-tetraoxide, silylated ; 1,3,5-Trithiane 1,1,3,3,5,5-hexaoxide, silylated ; Disulfenes, unsaturated ; Disulfenes, dianions of ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sulfoxonium ylides 3a-h were synthesized by silylation of the cyclic methylene disulfones 1,3-dithietane 1,1,3,3-tetraoxide (1) and 1,3,5-trithiane 1,1,3,3,5,5-hexaoxide (4) with the silylating agents silyl nonafluorobutanesulfonates. The structure and constitution of the ylides were established with 1H-NMR, 13C-NMR, 29Si-NMR spectroscopy, mass spectrometry, and elemental analysis. On the route to the sulfoxonium ylides a new class of unsaturated disulfenes 7, 8, 12, 13 of 1 and 4 were synthesized via Knoevenagel and substitution reactions. Dianions of newly formed alkyl disulfenes 16a, b, e, f, and the trianion 17 were prepared and characterized by 1H-NMR and 13C-NMR spectroscopy and compared with the results of the ylides.
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  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 405-410 
    ISSN: 0009-2940
    Keywords: Osmium(0) complexes ; Nitrosyl complexes ; CS2, COS, SCNPh, and Ph2C=C=O as bidentate ligands ; Protonation and methylation reactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of CS2 and Other Heteroallenes to the 16-Electron Osmium(0) Complexes trans-[OsCl(NO)(PiPr2R)2]The coordinatively unsaturated 16-electron compounds trans-[OsCl(NO)(PiPr2R)2] (1: R = iPr; 2: R = Ph) react with CS2 and COS to form the 1:1 adducts [OsCl(NO){κ2(C,S)-S=C=S}(PiPr2R)2)] (3, 4) and [OsCl(NO){κ2(C,S)-S=C=O}-(PiPr2R)2] (6, 7), respectively. While compounds 3, 4 are inert toward PMe3, the Os(COS) complexes 6, 7 react with tri-methylphosphane by abstraction of sulfur to give (OsCl(NO)-(CO)(PiPr2R)2] (8, 9). From 1 or 2 and phenylisothiocyanate the corresponding 1:1 adducts (OsCl(NO){κ2(C,S)-S=C=NPh}(PiPr2R)2] (10, 11) are obtained. Protonation and methylation reactions of 10 (R = iPr) with HBF4 or CF3SO3Me lead, by addition of the electrophile to the C=N nitrogen atom, to the formation of [OsCl(NO){κ2(C,S)-S=CNHPh}-(PiPr3)2]BF4 (12) and [OsCl(NO){κ2(C,S)-S=CN(Me)Ph}-(PiPr3)2]CF3SO3 (13). Treatment of 1 with diphenylketene yields [OsCl(NO){κ2(C,O)-O=C=CPh2}(PiPr3)2] (14). The X-ray structure analyses of 10 and 14 confirm the coordination of phenylisothiocyanate via S and C and of diphenylketene via O and C, respectively.
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