MNDO STUDY OF VICINAL DIHYDRIDES OF C-70 - INTERPRETATION OF RELATIVESTABILITY ON THE BASIS OF ELECTRONIC AND MOLECULAR-STRUCTURES

The structures and stability of isomeric vicinal dihyrides of C-70 are computed at the MNDO level. Their predicted stability is interpreted by comparing their electronic and molecular structures with those of C -70. While the two most stable isomers correspond to those obtained by hydrogenating the two most electron-rich bonds in C-70, the variation s in the relative stability of the other isomers do not strictly paral lel the bond orders of the bonds being hydrogenated. Changes in angle strain and the extent of pi reorganization accompanying hydrogens addi tion are suggested to control the relative stability of the C70H2 isom ers.