STRUCTURE AND BONDING OF CH2LI2 DIMERS

As models for polymeric dilithiomethane, a number of head-to-tail andhead-to-head CH2Li2 dimer structures were optimized by means of ab initio molecular orbital calculations using the RHF/STO-3G minimal basis method. Split valence basis RHF/4-31G single point calculations indicated VIII, with four lithium atoms bridging two perpendicular CH2 units, to be the most stable geometry for (CH2Li2)2. The dimerization energy at this level of theory, 37 kcal/mole, is already considerable; it should be even larger with higher association. Possible trimer and polymer structures are suggested. © 1978.