Nature of carbon-lithium bonding in dilithiated polynuclear aromatics: an MNDO study

Abstract

An MNDO study shows that the nonsymmetric crystal structures of dilithionaphthalene and dilithioanthracene are not the result of crystal-packing forces, but rather reflect the internal minimum energy arrangement of the molecules considered. On the other hand, the optimal structures of the complexes of the respective dianions with two positive charge are symmetrical. This difference suggests that partial covalency of the carbon-lithium bonding may be responsible for the nonsymmetric arrangement becoming the most stable in the crystal state.