摘要:

AbstractHigh‐quality SCF‐MO calculations yield a barrier to internal rotation of 1.70 kJ mole−1for Ge2H6. A new contraction scheme is reported for Dunning's larger Ge basis set. Geometry optimization, although carried out, is unimportant in this particular calculation. Wavefunctions and properties are reported for GeH4and the staggered and eclipsed conformers of Ge2H6. The magnitude of the calculated barrier is more physically reasonable than those deduced from experimental data. Comparisons are made across the two series X2H6and C

ISSN:0192-8651    

DOI:10.1002/jcc.540010212

出版商:John Wiley&Sons, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractA MINDO/3 study of homoaromaticity in the 3‐cyclobutenyl cation and the Mobius 3‐cyclobutenyl anion has been used to evaluate cationic and anionic homoaromaticity quantitatively. π Homodelocalization energies of the two are found equal in isostructural planar comparisons. In planar optimized structures, the homodelocalization energy of the cation is slightly (about 4 kcal) greater than that of the anion, a consequence of the greater 1,3 distance in the latter. Full optimization produces a highly puckered and further stabilized cation, but engenders no change in the Mobius anion. The total stabilization of the cation relative to the anion is 13 kcal, in accord with the generalization that cationic homoaromaticity is more potent than the anionic variety. The fully optimized cation is revealed to actually have a much smaller π homodelocalization energy than the optimized anion, in contrast to the order of overall stabilities. σ‐Nonclassical effects, which are stabilizing in the cation but destabilizing in the Mobius anion, provide the rationale for t

ISSN:0192-8651    

DOI:10.1002/jcc.540010213

出版商:John Wiley&Sons, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractThe energies of various conformations have been calculated by molecular mechanics for cis and trans isomers of 2,4,7,9‐tetraoxabicyclo[4.4.0] decane and 3,5,8,10‐tetraoxabicyclo[5.3.0]decane and their methyl derivatives. These molecules are models for reaction products from formaldehyde and the tetrols, pentitols, and hexitols. The conformational equilibria were analyzed for thecis‐bicyclo [4.4.0] andcis‐bicyclo[5.3.0] systems and compared with available experimental data. The thermodynamic stability of bicyclo[4.4.0]products was found to be higher than that of bicyclo[5.3.0] derivatives in the gas phase in every case studied. Discrepancies with experimental data that exist in a few cases can be ascribed to solvent

ISSN:0192-8651    

DOI:10.1002/jcc.540010214

出版商:John Wiley&Sons, Inc.    

年代:1980

数据来源: WILEY

摘要:

AbstractOpen (1) and cyclic (2) singlet forms of CO3were investigated by means ofab initiocalculations. At the highest level of theory employed,MP2/6‐31G* (which includes the effects of electron correlation),2was indicated to be much more stable than1and thermodynamically stable toward dissociation into CO2and O(3P). The open form1has a long OO bond and can be regarded as a weak dative complex between CO2and a singlet oxygen a

ISSN:0192-8651    

DOI:10.1002/jcc.540010215

出版商:John Wiley&Sons, Inc.    

年代:1980

数据来源: WILEY

ISSN:0192-8651    

DOI:10.1002/jcc.540010201

出版商:John Wiley&Sons, Inc.    

年代:1980

数据来源: WILEY