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  • 1990-1994  (17)
  • 1990  (17)
  • Inorganic Chemistry  (12)
  • Polymer and Materials Science  (3)
  • Organic Chemistry  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Thermodynamic cycle-perturbation study of the binding of trifluoroacetyl dipeptide anilide inhibitors with porcine pancreatic elastase (1990)
    New York : Wiley-Blackwell
    Biopolymers 30 (1990), S. 773-780 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The variety of results of crystallographic studies of the serine proteases complexed with isocoumnrin inhibitors presents a challenging problem to modeling methods and molecular energetics. Therefore, the thermodynamic cycle-perturbation technique has been used to study a model system of elastase and two peptidic inhibitors. Using the program AMBER, the technique correctly predicts changes of the binding constants for the trifluoroacetyl dipeptide inhibitors in comparison with available experimental (kinetic and crystallographic) data. However, the absolute values obtained are shown to be sensitive to the specific electrostatic interaction potential parameters used in the simulations. The reader and user are cautioned that thermodynamic cyle-perturbation results may be too optimistic by underestimating the accuracy of free energy values. This is especially a matter of concern for those cases where a direct comparison with experimental values is not possible, viz., (1) the simulation of binding of novel compounds, (2) structurally uncertain binding sites, or (3) structurally different binding modes. With our best 4-31G* ESP (electrostatic potential) charges we were able to reproduce experimentally determined free energy differences (ΔΔA) with an accuracy of about 1.5 kcal/mol. Dynamically induced structural changes in the binding site of elastase, and particularly changes in hydrogen-bond patterns of the binding site, are also reported.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360300712
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  • 2
    Electronic Resource
    Electronic Resource
    Übergangsmetall-Silyl-Komplexe, 34 Ein zweikerniger Gold-Silyl-Komplex mit Gold-Gold-Wechselwirkung zwischen einer (R3P)2Au- und einer (R′3Si)ClAu-Einheit (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 791-793 
    Details
    ISSN: 0009-2940
    Keywords: Gold complex, dinuclear / Silyl complex / Gold - gold interaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition-Metal Silyl Complexes, 34. - A Dinuclear Gold Silyl Complex with Gold- Gold Interaction Between an (R3P)2Au and an (R′3,Si)ClAu UnitPh2MeP-Au-Cl reacts with Ph2MeP-Au-SiPh3 to form the dinuclear complex (Ph2MeP)2Au2(Cl)SiPh3, which is in equilibrium with its starting compounds. An X-ray structure analysis reveals that it consists of a (Ph2MeP)2Au and a (Ph3Si)ClAu unit, which are held together by Au-Au interaction [298.07(4) Pm]. The approximately linear AuL2 units are orthogonal to each other.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230423
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  • 3
    Electronic Resource
    Electronic Resource
    Synthese und Reaktionen von Hydrido(oxim)-, Hydrido(oximato)- und Alkenyl(oximato)-Komplexen des Rutheniums und Osmiums (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 697-702 
    Details
    ISSN: 0009-2940
    Keywords: Osmium complexes/Oximato ligands, bidentate/Ruthenium complexes/Ring opening, ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Reactions of Hydrido(oxime), Hydrido(oximato) and Alkenyl(oximato) Complexes of Ruthenium and OsmiumThe carbonyl(hydrido) complexes MHCl(CO)[PMe(tBu)2]2 (4: M = Ru; 5: M = Os) react with aldoximes and ketoximes to give the octahedral hydrido(oxime)ruthenium and -osmium compounds MHCl(CO)[N(OH)=CRR′](PMe(tBu)2]2 (8-13) in high yields. Using MHCl(CO)(PiPr3)2 (6, 7) as starting materials, the complexes MHCl(CO)[N(OH)=CRR′](PiPr3)2 (14-16) are obtained. Reactions of 9 (M = Os; R = R′ = CH3) illustrate that the oxime ligand in the hydrido(oxime) compounds is easily displaced by Lewis bases. Either from 4, 5 and Na[N(O) = CRR′] in methanol or from 8-13 and NaH in THF the hydrido(oximato) complexes 20-25 in which the oximato ligand is coordinated via N and O, are formed almost quantitatively. CO opens the three-membered ring by cleavage of the M-N bond. Analogously, the alkenyl(oximato) compounds 28-30 are obtained from M[(E)-CH = CHPh]Cl(CO)[PMe(tBu)2)2]2 (18: M = Os; 27: M = Ru) with Na[N(O) = CRR′].
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230408
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  • 4
    Electronic Resource
    Electronic Resource
    A vivid model illustrating chiral recognition induced by achiral structures (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 2 (1990), S. 208-210 
    Details
    ISSN: 0899-0042
    Keywords: enantioselectivity ; three-point model ; didactic model ; chiral separations ; ligand-exchange chromatography ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: If diastereomeric complexes are adsorbed on a surface or if they include a molecule of solvent, two points of attractive interaction between the chiral species of the complex can be sufficient for mutual chiral recognition of these species. In special cases even one single point of interaction is sufficient. This extension of the three-point contact rule of Dalgliesh, first observed in chiral ligand-exchange chromatogrphy, can be demonstrated by using hands.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530020403
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  • 5
    Electronic Resource
    Electronic Resource
    Reversed-Phase LC resolutions of chiral antiarrhythmic agents via derivatization with homochiral isothiocyanates (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 2 (1990), S. 43-51 
    Details
    ISSN: 0899-0042
    Keywords: mexiletine ; flecainide ; tocainide ; propafenone ; chirality ; enantiomers ; HPLC ; homochiral derivatization ; isothiocyanates ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The search for new antiarrhythmic agents has been intense, because the established drugs for the treatment of cardiac arrhythmias are neither uniformly effective nor well-tolerated. Among the recently introduced new anti-arrhythmic agents are tocainide (TOC), mexiletine (MEX), flecainide (FLE), and propafenone (PRO). Each of these drugs is a chiral amine used clinically as the racemic mixture. We have examined the high-performance liquid chromatographic chiral resolution of the above four drugs via derivatization with homochiral derivatizing agents (HDAs). The amino functionality of the drugs was reacted with four homochiral isothiocyanates, 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate (TAGIT), (R)-α-methylbenzyl isothiocyanate (RAMBI), (S)-1-(1-naphthyl)ethyl isothiocyanate (SNEIT), and (R)-1-(2-naphthyl)ethyl isothiocyanate (RBEIT). Complete separation of the two peaks (resolution factor R = 1.5) was achieved with all four HDAs for TOC, with TAGIT, RBEIT, and RAMBI for MEX, with TAGIT and SNEIT for PRO, and only with TAGIT for FLE. SNEIT was used to develop analytical procedures for the determination of the enantiomeric composition of TOC in human urine and blood serum. The four HDAs offer several advantages over many other HDAs and should be useful in studies of enantioselective drug action and disposition.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530020107
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  • 6
    Electronic Resource
    Electronic Resource
    Dynamic properties of the first enzymatic reaction steps of porcine pancreatic elastase. How rigid is the active site of the native enzyme? Molecular dynamics simulation (1990)
    New York : Wiley-Blackwell
    Biopolymers 30 (1990), S. 781-796 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two molecular dynamics simulations (100 and 50 ps) of native porcine pancreatic elastase i.e., without bound substrate and with the active site hydrated by a dome of water (630 molecules) have been performed. Dynamical properties of the catalytic tetrad have been examined. While relative conformations of the Asp 102, His 57, and Ser 214 are rather stable in time, the side chain of Ser 195 undergoes several conformational changes. No preferences are observed for the formation of a hydrogen bond between the Oγ—H group (Ser 195) and nitrogen N∊ (His 57). A cluster of ordered water molecules effectively competes with the H—Oγ group (Ser 195) and thereby prevents the formation of this H bond, which is generally agreed to be crucial for catalysis.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360300713
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  • 7
    Electronic Resource
    Electronic Resource
    Ternäre Bromide des Aluminiums, Galliums und Indiums vom Typ AIMIIIBr4 (AI = Na, Ga, K, In, Rb) Eine Übersicht (1990)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 585 (1990), S. 38-48 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ternary Bromides of Aluminium, Gallium, and Indium of the Formula Type AIMIIIBr4 (AI = Na, Ga, K, In, Rb). An OverviewThe fourteen possible bromides AIMIIIBr4 with AI = Na, Ga, K, In, Rb and MIII = Al, Ga, In are obtained from mixtures of the binary components, ABr and MBr3. Six different structure types are observed: NaGaBr4-, NaAlCl4-, GaCl2-, β-GaBr2-, KAlBr4-, and BaSO4-type. Singlecrystal data are reported for the examples of NaGaBr4, KGaBr4, and InGaBr4. Without exception, slightly distorted tetrahedra [MBr4]- occur. The structural variety must be sought in the adjustment of the coordinational needs of the counter cations A+ (coordination numbers between six and twelve).
    Notes: Die 14 möglichen Bromide AIMIIIBr4 (AI = Na, Ga, K, In, Rb; MIII = Al, Ga, In) erhält man aus Gemengen der binären Komponenten, ABr und MBr3. Es treten sechs unterschiedliche Strukturtypen auf: NaGaBr4-, NaAlCl4-, GaCl2-, β-GaBr2-, KAlBr4- bzw. BaSO4-Typ. Einkristalldaten werden für die Beispiele NaGaBr4, KGaBr4 und InGaBr4 mitgeteilt. Stets liegen (leicht verzerrte) Tetraeder [MBr4]- vor. Die strukturelle Vielfalt ist in der Anpassung an die Koordinationsbedürfnisse der Gegenkationen A+ (Koordinationszahlen zwischen 6 und 12) zu suchen.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19905850105
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  • 8
    Electronic Resource
    Electronic Resource
    Addition und Substitution von Natrium in Cer(III)-chlorid: Na0,38(Na0,19Ce0,81)Cl3Professor Hans-Joachim Seifert zum 60. Geburtstage am 9. November 1990 gewidmet (1990)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 589 (1990), S. 96-100 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition and Substitution of Sodium to/into Cerium(III) Chloride: Na0.38(Na0.19Ce0.81)Cl3The action of sodium on CeCl3 (sealed tantalum ampoule, 750°C, 7 d) yields single crystals of the composition Na0,38(2)(Na0.193(3)Ce0.808(3))Cl3 (hexagonal, P63/m, Z = 2; a = 757.07(4); c = 431.56(3) pm, single-crystal data). The crystal structure may be viewed at as a substitution (Na0,19Ce0,81) plus addition (Na0,38) variant of CeCl3 (UCl3 type of structure).
    Notes: Bei der Einwirkung von Natrium auf CeCl3 (verschweißte Ta-Ampulle, 750°C, 7 d) erhält man Einkristalle der Zusammensetzung Na0,38(2)(Na0,193(3)Ce0,808(3))Cl3 (hexagonal, P63/m, Z = 2; a = 757,07(4); c = 431,56(3) pm, Einkristalldaten). Es liegt eine Substitutions-(Na0,19Ce0,81) und Additionsvariante (Na0,38) des CeCl3 (UCl3-Typ) vor.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19905890111
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  • 9
    Electronic Resource
    Electronic Resource
    Das komplexe Kation [(AnH)3(H2O)2]3+ in Trianilinium-tri-μ-chloro-nonachloro-trirhenat(III)-dihydrat, (AnH)3[Re3(μ-Cl3)Cl9] · 2 H2OProfessor Dietrich Babel zum 60. Geburtstage am 28. Juli 1990 gewidmet (1990)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 587 (1990), S. 16-22 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Cation [(AnH)3(H2O)2]3+ in Trianilinium-tri-μ-chloro-nonachloro-trirhenate(III)-dihydrate, (AnH)3[Re3(μ-Cl3)Cl9] · 2 H2ODark red single crystals of trianilinium-tri-μ-chloro-nonachloro-trirhenate(III)-dihydrate grow from hydrochloric acid solutions of “ReCl3 · 2 H2O” and anilinium hydrochloride. An important feature of the crystal structure (monoclinic, P21/a, Z = 4, a = 1595.98(12), b = 1594.53(11), c = 1319.65 (9) pm, β = 100.20(1)°, Vm = 497.68(1) cm3 mol-1) are complex cations of the composition [(AnH)3(H2O)2]3+. The N—O- and O—O-distances in the hydrogen bonded cation [(AnH)3(H2O)2]3+ are 281 to 289 pm and 287, respectively. The cationic layers build up corrugated layers parallel (010) and leave two channels in the [010] direction per unit cell into which the anionic clusters, [Re3Cl12]3-, are embedded.
    Notes: Dunkelrote Einkristalle von Trianilinium-tri-μ-chloro-nonachloro-tri-rhenat(III)-dihydrat erhält man aus salzsauren Lösungen von „ReCl3 · 2 H2O“ und Aniliniumhydrochlorid. In der Kristallstruktur (monoklin, P21/a, Z = 4, a = 1595,98(12), b = 1594,53(11), c = 1319,65(9) pm, β = 100,20(1)°, Vm = 497,68(1) cm3 mol-1) sind drei Aniliniumkationen und zwei Wassermoleküle über Wasserstoff-Brückenbindungen zu einem komplexen Kation [(AnH)3(H2O)2]3+ verbunden. Innerhalb dieser Baugruppe findet man N—O-Bindungsabstände zwischen 281 und 289 pm sowie einen O—O-Abstand von 287 pm. Die komplexen Kationen [(AnH)3(H2O)2]3+ sind parallel (010) zu gewellten Schichten angeordnet, die je Elementarzelle zwei Kanäle in Richtung [010] freilassen, in die die Anionen [Re3Cl12]3- eingebettet sind.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19905870103
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  • 10
    Electronic Resource
    Electronic Resource
    Das System NazGdClHx/S I. Die Kristallstruktur von NaGdCl4 (1990)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 590 (1990), S. 103-110 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The System NazGdClHx/S. I. Crystal Structure of NaGdCl4NaGdCl4 is obtained together with Gd2S3 through oxidation of Na0.25GdClH0.75 with sulfur (sealed tantalum container, 850°C, 7 d) as colourless single crystals or as a white powder by thermal decomposition of (NH4)2NaGdCl6 (320°C). The crystal structure (triclinic, P1, a = 702.81(6), b = 676.25(5), c = 666.72(5) pm, α = 100.852(7), β = 91.702(7), γ = 89.760(7)°, R = 0.040, Rw = 0.032) may be derived from the fluorite type although both Na+ and Gd3+ have coordination numbers (C.N.) of seven (monocapped trigonal prism). The structure may also be described as a layer structure where puckered layers are stacked along [100] in the sequence Cl2GdCl2NaCl2GdCl2 with Cl3 and Cl4 in four-fold cationic coordination and Cl1 and Cl2 with C.N. 3.
    Notes: NaGdCl4 entsteht neben Gd2S3 bei der Oxydation von Na0,25GdClH0,75 mit Schwefel (Tantal-Ampulle, 850°C, 7 d) in Form von farblosen, derben Einkristallen oder durch thermischen Abbau von (NH4)2NaGdCl6 (320°C) als weißes Pulver. Die Kristallstruktur (triklin, P1; a = 702,81(6); b = 676,25(5); c = 666,72(5) pm; α = 100,852(7); β = 91,702(7); γ = 89,760(7)°; R = 0,040; Rw = 0,032) leitet sich vom Fluorit-Typ ab, jedoch weisen Na+ und Gd3+ jeweils die Koordinationszahl 7 (bekapptes trigonales Prisma) auf. Sie kann auch als Schichtstruktur beschrieben werden: Gewellte Schichten werden gemäß Cl2GdCl2NaCl2GdCl2 längs [100] gestapelt, wobei Cl1 und Cl2 C.N. 3, Cl3 und Cl4 aber C.N. 4 aufweisen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19905900111
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