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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2765-2774 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Direct Metal Exchange in Phosphinidene-Bridged FeCo2 ClustersThe reactions of the clusters RPFeCo2(CO)9 (1a, R = Me; 1b, R = t-Bu) with [CpNiCO]2 (2) yielded product mixtures which originate from metal exchange reactions as well as from cluster rearrangement and ligand exchange. The crystal structures of the resulting clusters (μ4-MeP)2-Fe2CoNiCp(CO)8 (4) and (μ3-t-BuP)FeCoNiCp(CO)6 (5) were determined.
    Notes: Die Umsetzung der Cluster RPFeCo2(CO)9 (1a, R = Me; 1b, R = t-Bu) mit [CpNiCO]2 (2) führte zu Produktgemischen, die sowohl aus Metallaustauschreaktionen als auch aus Cluster-Umlagerung und Ligandenübertragung resultieren. Von den dabei entstehende Clustern (μ4-MeP)2-Fe2CoNiCp(CO)8 (4) und (μ3-t-BuP)FeCoNiCp(CO)6 (5) wurden Kristallstrukturanalysen durchgeführt.
    Additional Material: 2 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2748-2764 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chid PFeCoM Clusters: Preparation by Metal Exchange and Investigation of the Optical ActivityThe clusters RPFeCo2(CO)9 (1, R = Me, t-Bu, Ph) react with the organometal dimethylarsenides Cp(CO)3M—AsMe2 (3, M = Mo, W) to form the substitution derivatives RPFeCo2(CO)8-AsMe2-M(CO)3Cp (4, M = Mo; 5, M = W) and the hetero clusters RPFeCoMCp(CO)8 (6, M = Mo; 7, M = W). With R = tert-butyl the tetranuclear clusters t-BuPFeCo2M(AsMe2)Cp(CO)8 (8, M = Mo, W) are isolated as reaction intermediates. From t-BuPCo3(CO)9 (2) and Cp(CO)3Mo-AsMe2 the cluster t-BuPCo2Mo(AsMe2)Cp(CO)6 (9) is formed. The structures of the molybdenum containing clusters 6a and 9 were determined. The compound MePFeCoWCp(CO)8 (7a) is separated into its enantiomers via substitution with the phosphane ligand (-)-menthyl-O—PPh2. The ORD data of these show little resemblance with those of the corresponding sulfurbridged clusters.
    Notes: Die Cluster RPFeCo2(CO)9 (1, R = Me, t-Bu, Ph) setzen sich mit den Organometall-dimethyl-arseniden Cp(CO)3M—AsMe2(3, M = Mo, W) zu den Substitutions-Derivaten RPFeCo2(CO)8-AsMe2 - M(CO)3Cp (4, M = Mo; 4, M = Mo; 5, M = W) und zu den Hetero-Clustern RPFeCoMCp(CO)8 (6, M = Mo; 7, M = W) um. Für R = tert-Butyl können dabei als Zwischenstufen die Vierkerncluster t-BuPFeCo2M(AsMe2)Cp(CO)8(8, M = Mo, W) isoliert werden. Aus t-BuPCo3(CO)9(2) entsteht mit Cp(CO)3Mo-AsMe2 der Cluster t-BuPCo2Mo(AsMe2)Cp(CO)6 (9). Von den molybdänhaltigen Clustern 6a und 9 wurden die Strukturen bestimmt. Die Verbindung MePFeCoWCp(CO)8 (7a) läßt sich mit dem Phosphanliganden (-)-Menthyl-O—PPh2 in die Enantiomeren zerlegen. Deren ORD-Daten zeigen wenig Verwandtschaft mit denen der entsprechenden schwefelverbrückten Cluster.
    Additional Material: 3 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 779-785 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Drug ligands ; Captopril ; Isoniazid ; Nalidixic acid ; Mercaptopurine ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Four drugs whose actions have a relation to the status of zinccontaining species in the human body were used as ligands in zinc complexes. Captopril (H2Cap) forms the compound [ZnCap] (1) presumed to be a coordination polymer with O and S coordination. Isoniazid, in the presence of zinc salts, is converted to 1,2-diisonicotinoyl hydrazide (H2Nih) which forms polymeric [Zn(Nih)NH3] (2) with trigonal-bipyramidal ZnO2N3 coordination. Nalidixic acid (HNal) and zinc perchlorate yield [Zn(HNal)2(H2O)2](ClO4)2 · 2 H2O (3) containing zinc in an octahedral ZnO6 environment. Mercaptopurine (H2Mer), in the presence of ammonia, forms [Zn(Mer)(NH3)2] . H2O (4) which is a coordination polymer containing tetrahedral ZnN4 units. The structures of [Zn(Nih)NH3], [Zn(HNal)2(H2O)2](ClO4)2 . 2 H2O, and [Zn(Mer)(NH3)2] . 2 H2O were determined diffractometrically.
    Additional Material: 4 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 1095-1103 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Tridentate ligands ; Tris(pyrazolyl)methane ; Reactivity ; Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tris(pyrazolyl)methane ligands in which two or three of the pyrazole carbon atoms bear organic substituents (L1-L7) were synthesized from chloroform and the corresponding pyrazole under phase transfer conditions. Their behavior towards zinc salts was found to span the range from no reaction at all to hydrolytic destruction. One hydrolysis product isolated and structurally characterized was the perchlorate complex [(HPz5)3Zn-OClO3]ClO4 (1), other ones were the 2:1 complexes (HPz3)2ZnBr2 (2) and (HPz6)2Zn(NO3)2 (3, HPzn = substituted pyrazole). Zinc perchlorate and tris(trimethylpy-razolyl)methane (L2) formed the octahedral binary complex [L22Zn](ClO4)2 (4) as evidenced by a structure determination. Zinc halides produced the 1:1 complexes L1 · ZnBr2 (5), L4 · ZnCl2 (6), and L4 · ZnBr2 (7), which according to the structure determinations of 6 and 7 contain tetrahedral ZnN2Hal2 units with only bidentate tris(pyrazolyl)methane ligands. In contrast, the zinc nitrate complex L4 · Zn(NO3)2 (8) was found to have an octahedral structure with mono- and bidentate nitrate and tridentate L4. The bromide complex 7 was converted by silver perchlorate hydrate into the labile compound [L4 · ZnBr]ClO4 (9) and then into the unstable product [L4 · Zn-OH2](ClO4)2 (10), both presumed to contain zinc in a tetrahedral ZnN3Br or ZnN3O environment, respectively. The ease of hydrolytic self-destruction prevented the exploitation of the reactivity of 9 and 10 in analogy to that of the corresponding tris(pyrazolyl)borate zinc complexes.
    Additional Material: 5 Ill.
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  • 5
    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.
    Additional Material: 4 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 283-289 
    ISSN: 0009-2940
    Keywords: Zinc ; Sulfonate ligands ; Perchlorates ; Coordination modes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempts are reported to incorporate sulfonate and perchlorate anions as ligands in zinc complexes of tripodal ligands. Using tris(benzimidazolylmethyl)amine (BIMA) only the aqua complexes [ (BIMA)Zn-OH2](RSO3)(ClO4) and [(BIMA)Zn-OH2](RSO3)2(R=CH3, CF3, p-tolyl) were accessible. Using substituted pyrazolylborates (Tp*), the same three sulfonate anions were found to be ligands in the complexes Tp*Zn-OSO2R. Spectroscopic evidence for perchlorate coordination in Tp*ZnClO4 · 2 DMSO conflicts with crystallograpic evidence against it in Tp*ZnClO4 · pyridine. The crystal structures of [(BIMA)Zn-OH2](CH3SO3)2, TpCum,MeZn-OS02CH3, TPtBu,MeZn-OSO2C6H4-p-CH3, and [TpCum,MeZn · NC5H5]ClO4 were determined.
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1251-1257 
    ISSN: 0009-2940
    Keywords: Zinc complexes ; Cysteine ligands ; Histidine ligands ; Imidazole ligands ; Pyrazolylborate ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Highly substituted pyrazolylborate ligands TpR,Me were used to limit the coordination number of zinc towards cysteine- and histidine-derived coligands. Monodentate thiolate attachment (→ 1a-f) was achieved with N- and C-protected cysteine, monodentate carboxylate attachment (→ 3) with N-protected histidine. C-protected cysteine was found to form a five-membered N,S-chelate ring (2). While imidazole coordination with N- and C-protected histidine could not be achieved, cationic pyrazolylborate-zinc-coligand complexes [TpZn-L]+ (4a, b) were obtained for L = 2-methylimidazole. The new complexes were characterized by their spectra and three structure determinations.
    Additional Material: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1241-1252 
    ISSN: 0009-2940
    Keywords: Organometallic complexes ; Cyanide bridges ; Structure elucidation ; Isomerizations ; Oxidation ; Mixed valent compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 21 new organometallic complexes of the type M-Cn-M′ containing the building blocks M, M′ = (CO)5Cr, (CO)5Mo, (CO)5W, Cp(CO)2Mn, Cp(CO)2Fe, Cp(CO)(CN)Fe, Cp(dppe)Fe, Cp(PPh3)2Ru, Cp(PPh3)Ni, and (PPh3)2Ag were obtained from the reagents M-Cn and M-X (X = leaving group). Among them are five pairs of linkage isomers M-CN-M′/M-NC-M′. Structure determinations of (CO)5Cr-CN-M′ with M′ = Fe(dppe)Cp, Ni(PPh3)Cp, Ag(PPh3)2 and of (CO)5Cr-NC-Fe(dppe)Cp have proved their identity and the linkage isomerism. Systematic variations of the v(CN) and v(CO) IR bands allow as assessment of the relative electron pair acceptor strengths of the building blocks M and M′ and a reliable identification of the individual linkage isomers. All dinuclear complexes are redox-active, showing at lease one reversible oxidation. The redox potentials are characteristically dependent upon the nature of the building blocks M and M′ and upon the orientation of the cyanide link (CN vs. NC), 6 oxidized complexes of the type [M-Cn-Fe(dppe)Cp]+ were prepared chemically and isolated as PF6 or BF4salts. The molecular structure of [(CO)5Cr-CN-Fe(dppe)Cp]BF4 is not significantly different from those of the corresponding neutral Cr-CN-Fe or Cr-NC-Fe complexes. Upon oxidation the v(CN) band of the complexes shifts to lower wavenumbers and becomes much more intense. The oxidized complexes show the paramagnetism due to one unpaired electron. They give rise to very intense metal-to metal charge-transfer bands in the near infrared region whose position was found to be characteristically dependent on solvent polarity of [(CO)5Cr-CN-Fe(dppe)Cp]BF4. A semiquantitative treatment of the optical and electrochemical measurements shows that the electron delocalization and metal-metal interaction in the oxidized dinuclear complexes is significant and that they belong to the class-II mixed-valence systems.
    Additional Material: 7 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2385-2408 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mixed Metal Clusters: Metal Exchange via Organometal DimethylarsenidesReactions of the methylidyne-tricobalt clusters YCCo3(CO)9 (1, Y = H, Me, Ph, p-Tol, F) with the organometal dimethylarsenides Cp(CO)3M—AsMe2 (2-4, M = Cr, Mo, W) initially yield the addition products 5-7 through CO replacement. From these by heating a Co—As fragment is eliminated, whereby the new mixed metal cluster YCCo2MCp(CO)8 (9-11) are formed. Of the MeCCo2Mo compound 10c the molecular structure was determined. The mixed metal clusters allow for CO substitution by which also their prochirality can be proved. Attempts to perform corresponding metal exchange reactions with other tetrahedral cobalt clusters (PhPCo3(CO)9, Co4(CO)12, HFeCO3(CO)12, CpNiCo3(CO)9) or with other organometal dimethylarsenides M—AsMe2 (M = Cp(CO)2Fe, (CO)5Mn, Me3P(CO)4Mn) were only partially successful.
    Notes: Die Umsetzung der Methylidin-tricobalt-Cluster YCCo3(CO)9 (1, Y = H, Me, Ph, p-Tol, F) mit den Organometall-dimethylarseniden Cp(CO)3M—AsMe2 (2-4, M = Cr, Mo, W) liefert zunächst durch CO-Austausch die Additionsprodukte 5-7. Aus diesen wird beim Erhitzen ein Co—As-Bruchstück eliminiert, wobei sich die neuen Hetero-Clusters YCCo2MCp(CO)8 (9-11) bilden. Von dem MeCCo2Mo-Vertreter 10c wurde die Molekülstruktur bestimmt. In den Hetero-Clustern ist CO-Substitution möglich, wodurch sich auch ihre Prochiralität nachweisen läßt. Versuche, entsprechende Metallaustauschreaktionen auch an anderen tetraedrischen Cobaltclustern (PhPCo3(CO)9, Co4(CO)12, HFeCo3(CO)12, CpNiCo3(CO)9) oder mit anderen Organometall-dimethylarseniden M—AsMe2 (M = Cp(CO)2Fe, (CO)5Mn, Me3P(CO)4Mn) durchzuführen, waren nur zum Teil erfolgreich.
    Additional Material: 2 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2409-2422 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mixed Metal Clusters: Metal Exchange via Dinuclear (Cyclopentadienyl)metal CarbonylsIn the tetrahedral cobalt cluster MeCCo3(CO)9 (2a) by means of the dinuclear (cyclopentadienyl)-metal carbonyls [CpM(CO)n+1]2 (1, M = Mo, W, Fe, Ni) one Co(CO)3 unit can be replaced by an isoelectronic unit CpM(CO)n. The best exchange reagent [CpNi(CO)]2 yields the corresponding mixed Co2Ni and Co3Ni clusters, resp. also with other YCCo3(CO)9 clusters (2, Y = Ph, p-Tol, F) and with Co4(CO)12. Thus, by combination of this method with the previously described organometal dimethylarsenide method from YCCo3(CO)9 (2, Y = Me, Ph) the clusters YCCoMoNiCp2(CO)5 (16) with three different metal atoms are obtained. Under modified reaction conditions twofold metal exchange in MeCCo3(CO)9 yields the cluster MeCCoMo2Cp2(CO)7 (15) and in PhCCo2MoCp(CO)8 yields the cluster PhCMoNi2Cp3(CO)2 (17). Of the CoMoNi compound 16a and the MoNi2 compound 17 the molecular structures were determined.
    Notes: In dem tetraedrischen Cobaltcluster MeCCo3(CO)9 (2a) läßt sich mit Hilfe der zweikernigen (Cyclopentadienyl)metallcarbonyle [CpM(CO)n+1]2 (1, M = Mo, W, Fe, Ni) eine Co(CO)3-Einheit durch eine isoelektronische Einheit CpM(CO)n ersetzen. Das beste Austausch-Reagens [CpNiCO]2 liefert auch mit anderen YCCo3(CO)9-Clustern (2, Y = Ph, p-Tol, F) und mit Co4(CO)12 die entsprechenden Co2Ni- bzw. Co3Ni-Heterocluster. Durch Kombination dieser Methode mit der vorstehend beschriebenen Organometall-dimethylarsenid-Methode lassen sich so aus YCCo3(CO)9 (2, Y = Me, Ph) die Cluster YCCoMoNiCp2(CO)5 (16) mit drei verschiedenen Metallatomen gewinnen. Unter veränderten Reaktionsbedingungen ergibt zweifacher Metallaustausch aus MeCCo3(CO)9 den Cluster MeCCoMo2Cp2(CO)7 (15) und aus PhCCo2MoCp(CO)8 den Cluster PhCMoNi2Cp3(CO)2 (17). Von der CoMoNi-Verbindung 16a und der MoNi2-Verbindung 17 wurden die Molekülstrukturen bestimmt.
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