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  • 1
    Electronic Resource
    Electronic Resource
    X-ray Crystal Structure of 3-Vinylcyclopropene. Gas Phase Synthesis of Simple Cyclopropenes (1994)
    s.l. : American Chemical Society
    The @journal of organic chemistry 59 (1994), S. 8125-8126 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00105a032
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  • 2
    Electronic Resource
    Electronic Resource
    Structure and photoelectron spectrum of 3,3'-bicyclopropenyl (1993)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 115 (1993), S. 743-746 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00055a052
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  • 3
    Electronic Resource
    Electronic Resource
    Low temperature crystal and molecular structure of nitrobenzene (1992)
    Springer
    Structural chemistry 3 (1992), S. 363-368 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The crystal and molecular structure of nitrobenzene was determined at 103 K by X-ray diffraction, yieldingR=0.034 and a highly precise geometry of the molecule (esds of bond lengths ≤0.001 Å and bond angles ≤0.1°). The bond angles in the ring agree very well with additive scheme based on angular substituent parameters. X-X electron density maps support the view that the C-N bond does not exhibitπ-character, and, hence, the nitro group interacts with the ring mostly by inductive effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00678559
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  • 4
    Electronic Resource
    Electronic Resource
    Comparative study by single crystal X-ray structure determinations of tetramethylaminoborane and tetramethylethene at 110 K (1992)
    Springer
    Structural chemistry 3 (1992), S. 399-406 
    Details
    ISSN: 1572-9001
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The single crystal structures of the two isoelectronic and isosteric compounds tetramethylaminoborane and tetramethylethene have been determined by an X-ray study at 110 K. The distances of the central bonds are refined to 140.3(1) pm (B=N) and 134.8(1) pm (C=C), the CXXC-torsion angles (XX=CC, BN) are smaller than 1° in both compounds. A bond-length-bond-order correlation for the aminoboranes [(CH3)2N] n B(CH3)3−n withn=1, 2, and 3 give a regression coefficient of 0.9977, the same is found for the CNC-angle as a function of the CBNC-torsion angle. Also, the comparison among these aminoboranes show that the variation of CBNC-torsion angles has more influence on bond lengths at small angles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00672014
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  • 5
    Electronic Resource
    Electronic Resource
    Heterocyclen als Liganden, X 2,2′,5,5′-Tetra-tert-butyl-1,1′-diazaferrocen  -  Stabilisierung der Diheterometallocen-Struktur durch sterische Abschirmung (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 89-91 
    Details
    ISSN: 0009-2940
    Keywords: Diazaferrocene derivative ; Iron complex ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterocycles as Ligands, X1).  -  2,2′,5,5′-Tetra-tert-butyl-1,1′-diazaferrocene - Stabilization of the Diheterometallocene Structure by Steric ShieldingStable 2,2′,5,5′-tetra-tert-butyl-1,1′-diazaferrocene (3) is obtained by the reaction of the corresponding lithiopyrrole with FeCl2. The X-ray analysis reveals a distorted sandwich structure influenced by repulsive interactions presumably both between the nitrogen atoms and the bulky tert-butyl substituents.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240115
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  • 6
    Electronic Resource
    Electronic Resource
    Kristallisiertes Natrium-triethylhydroborat  -  Bildung und Charakterisierung (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2259-2262 
    Details
    ISSN: 0009-2940
    Keywords: Hydroborate ; triethyl ; sodium salt ; Sodium  -  arene addition compound ; Mesitylene ; Tricoordinated H atoms ; Solid-solid phase transformation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystalline Sodium Triethylhydroborate  -  Formation and CharacterizationTwo equiv. of NaHBEt3 (1) and one equiv. of mesitylene form a crystalline compound, which is characterized by DSC and by a single-crystal X-ray structure analysis at 190 K as the solid phase 2.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241019
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  • 7
    Electronic Resource
    Electronic Resource
    Umlagerung und Abbau bicyclischer Amin - Tetraorganodiboroxane[1] (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 1843-1849 
    Details
    ISSN: 0009-2940
    Keywords: Amine-Diboroxanes, bicyclic ; 1,2-Deaminoboration, intramolecular ; Deoxyboration ; Allyl-aminoboranes, organosubstituted, rearrangement ; C-Borylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rearrangement and Degradation of Bicyclic Amine-Tetraalkyldiboroxanes[1]The amine-tetraalkyldiboroxanes [1a: R1,4,7,7′ = Et; 1b: R1,4,7 = Et, R7′ = Ph; 1b′: R4,7,7′ = Et,R1 = Ph; 1c: R1,7,7′ = Et, R4 = Ph] react on heating by EtBO elimination and allylborane rearrangement to yield the allyl-aminoboranes Me2NB(Et)CH2C(R4)=C(R7,7′) [2a: R4,7,7′ = Et; 2b/2b′: R4 = Et, R7,7′ = Et, Ph; 2c: R4 = Ph, R7,7′ = Et]: On heating above 60°C the diastereomeric syn/anti-Id/1d′(Id: R1,7 = C8H14, R4,7′ = Et; 1d′: R1,7′ = C8H14, R4,7 = Et) give the unsaturated rac-amino-trialkyldiboroxane (rac-3) (X-ray structure analysis) by intramolecular 1,2-deaminoboration. rac-3 is characterized by reaction with (Et2BH)2 and (Et2BD)2 with formation of the 1,2,6-oxadiborinane 5 by evolution of H2 or HD respectively. The intramolecular CH-borylation of rac-3 is compared with those of the thujopsen hydrocarbons I-III.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941271005
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  • 8
    Electronic Resource
    Electronic Resource
    Vinamidin-Chelate des Bors (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1301-1306 
    Details
    ISSN: 0009-2940
    Keywords: 1,3,2-Diazaborinies, dihydro- ; Protonation ; Calculations, AMI, 4-31G ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Vinamidine Boron Chelate CompoundsThe chelate compound 7 is obtained by the reaction of the vinamidine 6 with Et2O - BF3. Protonation with HBF4 gives the cation 11. Comparison of the calculated and experimentally determined structures demonstrates 7 and 11 to be heterocyclic analogues of the cyclohexadienide 5 and 1,4-cy-cyclohexadiene (12).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230613
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  • 9
    Electronic Resource
    Electronic Resource
    1,2-Azaborolyl-Komplexe, XXVIII. (η5-1-tert1-Butyl-2-methyl-1,2-azaborolyl)carbonyl-Phosphan-und -Olefin-Cobalt-Komplexe (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 899-906 
    Details
    ISSN: 0009-2940
    Keywords: 1,2-Azaborole ligand ; Cobalt complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,2-Azaborolyl Complexes, XXVIII[1]. - (η5-1-tert1-Butyl-2-methyl-1,2-azaborolyl)carbonyl Phosphane and -Olefin Cobalt ComplexesBy using (η5-1-tert1-butyl-2-methyl-1,2-azaborolyl)dicarbonyl-cobalt [η51-AbCo(CO)2] (1) as starting material, various phos-phane and olefin derivatives of the type AbCo(CO)L are synthesized. The phosphanes L=PMe3, PEt3, P(nPr)3, P(nBu)3, and P(OPh)3 give, due to the chirality of 1, the enantiomeric compounds 2-6, whereas the phosphanes P(tBu)MePh, P(OsBu)Ph2, and PPh2 [OCH(CH3)CO2CH3] form the diaster-eoisomers 7-9. The orange-red, oily and volatile compounds are isolated with yields between 30 and 60%. The mechanism of formation of [η51-AbCo(CO)PMe3] (2) has been studied by means of intermediates at low temperatures. To avoid a 20e configuration when PMe3 is added to 1, the allyl complex [η31-AbCo(CO)2PMe3] (2a) is formed. With an excess of PMe3 it can even be transferred into the mono-hapto complex [η11-Ab-Co(CO)2(PMe3)2] (2b) with a Co - C-3 s̰ bond. 2a as well as 2b change to [η51-AbCo(CO)PMe3] (2) when warmed up to room temperature. In contrast to substitution reactions of [Cp-Co(CO)2] where intermediates have never been observed, here an addition-elimination process is proved. With dimethyl ma-leate, maleic anhydride, and methylmaleic anhydride three olefin complexes 10, 11, and 12 are obtained. However, 10 contains the fumaric ester, due to a cis-trans isomerisation during the complexation. X-ray structure analyses prove the molecular structures of 11 and 12. The original goal of this project, namely to prepare pure enantiomeric [η51-AbCo-(CO)olefin] half-sandwich complexes in order to study the ster-eoselective influence of the Ab ring on addition reactions to the olefin ligands could not yet be reached.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260408
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  • 10
    Electronic Resource
    Electronic Resource
    1,2-Azaborolyl-Komplexe, XXIX. Synthese und Eigenschaften von 1,2-Azaborolylboranen (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 73-80 
    Details
    ISSN: 0009-2940
    Keywords: 1,2-Azaborolylboranes ; Iron complexes ; Sandwich complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,2-Azaborolyl Complexes, XXIX[1].  -  Synthesis and Properties of 1,2-AzaborolylboranesThe Li salts of variously substituted 1,2-azaboroles 1a-1c react with numerous halogenoboranes to give the corresponding mono(1,2-azaborol-3-yl)boranes 2-12. In the case of 11, which is substituted by SiMe3 at C-3, 2,5-dihydro isomers can be observed as intermediates by NMR spectroscopy with a B(Cl)NMe2 group at C-5 and the SiMe3 substituent either at C-4 (11a) or at C-3 (11b). The thermodynamically stable final product 11 is probably formed from 11b via an allylic transition state. The X-ray structure analysis of 11 at ca. 0°C proves the suggested structure. The first and only example of a bis(1,2-azaborol-3-yl)borane 13 was realized by the reaction of (1-tert-butyl-2,3-dihydro-2-methyl-1H-1,2-azaborol-3-yl)-chloro(dimethylamino)borane (3) with 1-tert-butyl-2-methyl-1,2-azaborolyllithium (1a). The X-ray structure analysis of bis(1-tert-butyl-2,3-dihydro-2-methyl-1H-1,2-azaborol-3-yl)-(dimethylamino)borane (13) shows one of the two NMR-spectroscopically observed diastereoisomers with perpendicularly oriented azaborolyl rings. Two iron sandwich complexes were synthesized; 15 is formed via 1-tert-butyl-3-[bis(dimethylamino)boryl]-2-methyl-1,2-azaborolyllithium (14) and FeCl2, whereas the ClB-substituted sandwich complex 16 results from the reaction of 15 with BCl3.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270111
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