MOLECULAR ORBITAL CALCULATION OF SOME GROUP I 2 AND 3 METHYL COMPOUNDS

The methyl compounds of the group I, II, and III elements display some interesting variations in structure. Some of the compounds are electron deficient in the sense that they form polymeric species through the derealization of one or more bonding pairs. Examples of the latter are ((CH3)3AI)2, (CH3Li)4, and ((CH3)2Be)J. By contrast other compounds such as (CH3)3B and (CH3)2Zn are monomers showing little or no tendency toward association. An attempt has been made to understand the bonding factors which are responsible for the variations in structure of the methyl compounds of lithium, beryllium, boron, and aluminum largely on the basis of charge-iterated extended Hückel molecular orbital calculations. CNDO-SCF calculations were also performed on CH3Li and (CH3Li)4. © 1969, American Chemical Society. All rights reserved.