Three isomers of the aluminum-acetylene system

摘要: Self-consistent field (SCF) wave functions were computed for several electronic states of each the three isomers. The ..pi..-bonded Al--C/sub 2/H/sub 2/ and 4/ dissociation energies are expected to be less than or equal 5 kcal/mol, even though effects extensive configuration interaction aluminum d explicitly considered. equilibrium geometries sigma-bonded vinylidine complexes illustrated. At SCF level theory sigma complex is bound by 8.0(trans) 8.2(cis) kcal, while 21.5 kcal relative infinitely separated + acetylene. Configuration including all valence electron single doublet excitations reduces ca 20 Al--CCH/sub bond energy. shorter Al--C internuclear separation also attests its stronger bond. Analogous studies trans-sigma-bonded yield a binding energy 7.5 kcal. structure inconsistent with another author's previously published ESR spectrum, apparently because reaction temperature. 1 figure.