2 ISOMERS OF THE LI2C2O2 MOLECULE - AN ABINITIO STUDY

Ab initio calculations at the HF/6-311G* and MP2/6-311G* levels reveal the existence of two isomers of the Li2C202 molecule. The linear structure corresponds to the dilithium salt of dihydroxyacetylene. The second stable structure possesses two four-membered rings, each consisting of one lithium, one oxygen, and two carbon atoms. At both the HF and MP2 levels, the two isomers are predicted to have very close energies. The GAPT atomic charges and vibrational frequencies are calculated for both structures, and the bonding is analyzed with the aid of Bader's topological theory of atoms in molecules. The results of the theoretical calculations rationalize the recent experimental observations. © 1990, American Chemical Society. All rights reserved.