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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 108 (1975), S. 3008-3013 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Complex Chemistry of Lower Sulfur Oxides, II. Sulfur Monoxide and Disulfur Dioxide as Complex LigandsThe sulfur oxides SO and S2O2, unstable under normal conditions, can act as complex ligands in [{C6H5)2PCH2CH2P(C6H5)2}2Ir(SO)2]Cl. The synthesis is achieved by oxidation of cis-[{(C6H5)2PCH2CH2P(C6H5)2}2Ir(S2)]Cl with sodium periodate. The complex forms two modifications, recognizable from the number of the v(SO) frequences in the i.r. spectrum. One of the modifications, containing disulfur dioxide as a ligand, was investigated by an X-ray structure analysis. trans Position of two single SO groups is supposed in the other modification. From this compound the SO molecules can be eliminated by (C6H5)3P as (C6H5)3P=O and (C6H5)3P=S with formation of [{(C6H5)2PCH2CH2P(C6H5)2}2Ir]Cl.
    Notes: Die unter Normalbedingungen instabilen Schwefeloxide SO und S2O2 können in [{C6H5)2PCH2CH2P(C6H5)2}2Ir(SO)2]Cl als Komplexliganden auftreten. Die Synthese erfolgt durch Oxidation von cis-[{(C6H5)2PCH2CH2P(C6H5)2}2Ir(S2)]Cl mit Natriumperjodat. Der Komplex bildet zwei Modifikationen, erkennbar an der Zahl der v(SO)-Schwingungen im IR-Spektrum. Von einer Modifikation, die das Dischwefeldioxid als Liganden enthält, wurde eine Röntgenstrukturanalyse durchgeführt. In der anderen Modifikation wird trans-Stellung zweier SO-Gruppen vermutet. Aus dieser Verbindung lassen sich die SO-Moleküle mittels (C6H5)3P als (C6H5)3P=O und (C6H5)3P=S unter Bildung von [{(C6H5)2PCH2CH2P(C6H5)2}2Ir]Cl entfernen.
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  • 2
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Polycarbonyls, XVI. Synthesis and Structure of the Sulfur Analogue of Squaric Acid Dianion K2[C4S4·H2O]Sulfhydrolysis of 1,2- or 1,3-dithiosquaric acid diamides yields the sulfur analogue 4 of squaric acid dianion, the first member of the „thioxocarbons“. Spectroscopic data and intramolecular distances determined by X-ray diffraction indicate a symmetrical, delocalised electron system with C—C- and C—S-bond orders of n - 1.25 and 1.5, resp.
    Notes: Durch Sulfhydrolyse von 1,2- bzw. 1,3-Dithioquadratsäure-bisamiden entsteht das Schwefelanalogon 4 des Quadratsäure-Dianions, der erste Vertreter der „Thioxokohlenstoffe“. Spektroskopische Daten und die aus einer röntgenographischen Strukturbestimmung erhaltenen innermolekularen Bindungslängen weisen auf ein symmetrisches, delokalisiertes Elektronensystem mit C — C- bzw. C — S-Bindungsordnungen von n = 1.25 bzw. 1.5 him.
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 2807-2814 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Structure of 1-Benzyl-1,4,4-trimethyl-1,2,6-thia(VI)diazine-3,5(4H)-dioneThe structure of thc title compound was elucidated by X-ray diffraction: space group P211/c, a = 8.947, b = 21.055, c - 7.688 Å, β = 113.61°, Z = 4, Dm = 1.31 g·cm-3, Dx = 1.323 g·cm-3, R = 2.7%. The thiadiazine ring deviates slightly from planarity. C-4 is 0.17 Å out of plane. So one of the methyl groups at C-4 gets van der Waals contact with the benzyl group at S, which explains the shift of the n.m.r. signal of that methyl group to higher field (τ = 9.6). The molecule obeys nearly mirror symmetry. Weak C—H…O hydrogen bonds exist between adjacent molecules, which are possible because of the limiting polar formula:
    Notes: Die Struktur dcr Titelverbindung wurde mittels Röntgenbeugung aufgeklärt: Raumgruppe P21/c, a = 8.947, b = 21.055, c = 7.688 Å, β = 113.61°, Z = 4 Moleküle/Zelle, Dm = 1.31 g·cm 3, Dx = 1.323 g·cm-3, R = 2.7%. Der Thiadiazinring ist nicht ganz eben, sondern C-4 knickt um 0.17 Å so aus der Ringebene heraus, daß sich die eine der daran gebundenen Methylgruppen der an S gebundenen Benzylgruppe bis zum van der Waals'schen Kontakt nähert. Dadurch kann das zu hohem Feld verschobene NMR-Signal (τ = 9.6) dieser Methylgruppe erklärt werden. Insgesamt ist das Molekül fast spiegelsymmetrisch. Zwischen benachbarten Molekülen bestehen schwache C—H…O-Wasserstoffbrücken, die durch die polare Grenzformel erklärt werden können.
    Additional Material: 4 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 109 (1976), S. 3005-3016 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Substituted Malonaldehydes, XXIIIγ-Cycloalkylpentamethinecyanine DyesCondensation of the cycloalkylmalonaldehydes 2a-d with heterocyclic imonium salts (1a-c) yields γcycloalkyl subsituted symmetric pentamethinecyanine dyes (3a-h). The introduction of a γ-cycloalkyl group causes a 2-8 nm hypsochromic (!) shift of the long wave length π-π* absorption band in the electronic spectra (table 1) according to a small (-1)-effect. This substituent effect, particularly unexpected in the case of a cyclopropyl group, suggests for the dyes 3a-c the existence of a perpendicular conformation of the cyclopropyl group relative to the all-trans pentamethine chain. This conclusion is confirmed by an X-ray analysis of 3a (fig.1-4).
    Notes: Durch Kondensation der Cycloalkylmalonaldehyde 2a-d mit heterocyclischen Imoniumsalzen (1a-c) werden γ-cycloalkylsubstituierte symmetrische Pentamethincyanin-Farbstoffe (3a-h) dargestellt. Die Einführung von γ-Cycloalkylgruppen bewirkt eine hypsochrome (!) Verschiebung der längstwelligen π-π*-Absorptionsbande um 2-8 nm im Elektronenspektrum (Tab. 1), entsprechend einem geringen (-I)-Effekt. Dieser besonders für die Cyclopropylgruppe unerwartete Substituenteneinfluß legt für die Farbstoffe 3a-c das Vorliegen einer Konformation nahe, in der die Ebene der Cyclopropylgruppe parallel zur all-trans-Pentamethinkette liegt. Eine Röntgenstrukturanalyse von 3a bestätigt diese Annahme (Abb. 1-4).
    Additional Material: 4 Ill.
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  • 5
    ISSN: 0009-2940
    Keywords: Chlorosilanes ; hexacoordinated/Silicon complexes ; octahedral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hexacoordinated Compounds of Trichlorosilanes. - Preparation, Crystal and Molecular Structure of BSiCl3·bipyThe octahedral Si complexes CHCl2SiCl3·bipy (1), CCl3SiCl3·bipy (2), and Cl3SiCCl2SiCl3·bipy (3) are obtained by the reaction of the respective trichlorosilanes and 2.2′-bipyridine (bipy). Their composition is independent of the initial ratio of the components. X-ray structure determinations show the Si atoms of all three complexes to be octahedrally coordinated with the substituted methyl groups in axial positions. The configurations represent structures of least steric hindrance assuming spheric substituents and demonstrate the usefulness of this structural model for solid compounds (in contrast possibly to dissolved compounds) even for substitutents deviating strongly from this assumption. Bond lengths and angles agree with the presence of hexacoordinated complexes. Deviations from expected values are interpreted in terms of considerable steric interactions. 3 represents a case of strongly hindered coordination requiring interesting steric adjustments.
    Additional Material: 5 Ill.
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  • 6
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of 1-Oxo-1H-pyrazolo[1,2-a][1,2,4]triazol-4-ium-3olates.  -  A Ring-Chain Tautomerism in the Series of Bicyclic Dipolar Heterocycles1-(Trimethylsilyl)pyrazole (12) reacts with chlorocarbonyl isocyanate to give a compound, which  -  dependent on the state of aggregation  -  may exist both as a bicyclic dipolar heterocycle (7) and as monocyclic 1-pyrazolyl carbonyl isocyanate (8). Methylsubstituted derivatives (19a, b) show a similar behaviour. MNDO calculations for the parent systems (7, 8) are in accord with these experimental observations. The structure of 5,6,7-trimethyl-1-oxo1H-pyrazolo[1,2-a][1,2,4]triazol-4-ium-3-olate (19b) has been clarified by X-ray analysis.
    Notes: 1-(Trimethylsilyl)pyrazol (12) reagiert mit Chlorcarbonylisocyanat zu einer Verbindung, die  -  in Abhängigkeit vom Aggregatzustand  -  sowohl als bicyclischer dipolarer Heterocyclus (7) als auch als monocyclisches 1-Pyrazolylcarbonylisocyanat (8) vorliegen kann. Methylsubstituierte Vertreter (19a, b) zeigen ein analoges Verhalten. MNDO-Rechnungen an den Grundkörpern (7, 8) stehen in Einklang mit diesen Experimentalbefunden. Die Struktur des 5,6,7-Trimethyl-1-oxo-1H-pyrazolo[1,2-a][1,2,4]-triazol-4-ium-3-olats (19b) wurde durch eine Röntgenstrukturanalyse geklärt.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3860-3874 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Reductive Elimination of the Biphenyl System from Substituted trans-Diphenylbis(triphenyl-phosphane)platinum(II) Compoundstrans-Diarylbis(triphenylphosphane)platinum(II) (aryl = C6H5, 3—CH3C6H4, 4—CH3C6H4, 3—CH3OC6H4, 4—CH3OC6H4, 3—(H3C)2NC6H4) (trans-1a-f) have been synthesized. The trans-configuration in this type of compounds is demonstrated by an X-ray analysis of the parent compound trans-[Pt(PPh3)2(C6H5)2]. The thermolysis of trans-1a-f yields  -  despite the trans-position of the phenyl rings  -  stereospecific reductive elimination of the biphenyl system in a concerted reaction.
    Notes: Die Verbindungen trans-Diarylbis(triphenylphosphan)platin(II) (Aryl = C6H5, 3—CH3C6H4, 4—CH3C6H4, 3—CH3OC6H4, 4—CH3OC6H4, 3—(H3C)2NC6H4) (trans-1a-f) wurden synthetisiert. Die trans-Konfiguration dieses Verbindungstyps wurde zusätzlich durch eine Röntgenstruktur-analyse der Stammverbindung trans-[Pt(PPh3)2(C6H5)2] belegt. Bei der Thermolyse von trans- 1a-f wurde  -  trotz der trans-Stellung der Phenyl-Ringe  -  in einer konzertierten Reaktion stereospezifisch das Biphenyl-System eliminiert. Der Mechanisms dieser reduktiven Eliminierung wird diskutiert.
    Additional Material: 2 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 887-894 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2H-1,3,4-Oxadiazin-2-ones. A New Class of Heterocyclic CompoundsMetal-catalyzed nitrogen extrusion from acyl(α-diazoacyl)hydrazines of type 7a-c,e yields the hitherto unknown 2H-1,3,4-oxadiazin-2-ones (9a-c,e). The Structure of 9a has been clarified by X-ray crystallography.
    Notes: Acyl(α-diazoacyl)hydrazine des Typs 7a-c,e liefern bei der metallkatalysierten N2-Eliminierung bislang nicht beschriebene 2H-1,3,4-Oxadiazin-2-one (9a-c,e). Von der Verbindung 9a wurde eine Röntgenstrukturanalyse angefertigt.
    Additional Material: 2 Ill.
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  • 9
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with Substituted Malondialdehydes, XVIII. Synthesis and Structure of Heteroanalogous Arylazomalondialdehydes and as-Triazino[4,3-b]-indazolesWhereas the coupling reaction of 3,5-dimethyl- (1) and 1-phenyl-4-pyrazolediazonium tetrafluoroborate (2) with malondialdehyde (3) led to the expected heteroarylazomalondialdehydes 4 and 5, the same reaction of 3-indazolediazonium tetrafluoroborate (6) with malondialdehyde, acetoacetaldehyde, and acetylacetone yielded surprisingly the as-triazino[4,3-b]indazoles 11 - 13. The detailed structure of 3-acetyl-4-methyl-as-triazino[4,3-b]indazole (13) was elucidated by X-ray diffraction (fig. 1 and 2). Weak C—H…N hydrogen bonds exist between adjacent molecules (fig. 2: H(8)…N(1),H(8)…N(2)and H(11)…N(13)). By comparing the experimental bond lengths with the calculated values obtained by the Pauling equation, the relative importance of the resonance structures 13a - e, was estimated by means of the simple valence bond method.
    Notes: Während bei der Kupplungsreaktion von 3,5-Dimethyl-(1) und 1-Phenyl-4-pyrazolidazonium-tetrafluoroborat (2) mit Malondialdehyd (3) die erwarteten Heteroarylazo-malondialdehyde 4 und 5 gebildet wurden, führte dieselbe Reaktion von 3-Indazoldiazonium-tetrafluoroborat (6) mit Malondialdehyd, Acetoacetaldehyd und Acetylaceton überraschend zu den as-Triazino-[4,3-b]indazolen 11 - 13. Die Feinstruktur von 3-Acetyl-4-methyl-as-triazino[4,3-b]indazol (13) wurde durch Röntgenbeugung aufgeklärt (Abb. 1 und 2). Zwischen benachbarten Molekülen bestehen schwache C—H…N-Wasserstoffbrücken (Abb. 2: H(8)…N(1), H(8)…N(2) und H(11)…N(13)). Durch Vergleich der experimentellen mit den nach Pauling berechneten Bindungslängen wurde mittels der einfachen Valenzstrukturmethode der relative Anteil der mesomeren Grenzstrukturen 13a - e am Elektronengrundzustand von 13 abgeschätzt.
    Additional Material: 3 Ill.
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  • 10
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Constitution, and X-ray Analysis of 4,4-Bis(1,1-dimethoxy-2,6-diphenyl-λ5-phosphorin-4-ylmethyl)-1-methoxy-1-oxo-2,6-diphenyl-1,4-dihydro-λ5-phosphorinOn experiments to synthesize the carbene 1 or a subsequent product of it by deprotonation of 1,1-dimethoxy-2,6-diphenyl-λ5-phosphorin-4-ylcarbenium tetrafluoroborate (2) with ethyldiiso-propylamine, we isolated bis(1,1-dimethoxy-2,6-diphenyl-λ5-phosphorin-4-yl)methane (6) and another compound, formed from 3 mols of 2. Its constitution as the title compound 9 could be determined only by X-ray analysis. 6 and 9 are formed by addition-elimination in analogy to an aromatic electrophilic substitution: the primary addition product is stabilized by splitting off in case 6 of CH2NR2⊕ (from 5), in case 9 of CH3⊕ (from 7).
    Notes: Der Versuch, 1,1-Dimethoxy-2,6-diphenyl-λ5-phosphorin-4-ylcarbenium-tetrafluoroborat (2) mittels Ethyldiisopropylamin zum Carben 1 oder dessen Folgeprodukte zu deprotonieren, führte zu Bis(1,1-dimethoxy-2,6-diphenyl-λ5-phosphorin-4-yl)methan (6) und einer weiteren, aus 3 mol 2 entstandenen Verbindung. Ihre Konstitution konnte nur durch eine Röntgenstrukturanalyse als die Titelverbindung 9 erkannt werden. 6 und 9 entstehen durch Addition-Elimination analog einer aromatischen elektrophilen Substitution: das primär gebildete Additionsprodukt stabilisiert sich durch Abspaltung bei 6 von CH2NR2⊕ (aus 5), bei 9 von CH3⊕ (aus 7).
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