| Research Abstract |
Several new silyl-substituted pi-electron systems, such as fulvene, dimethylenecyclobutene, trimethylenecyclopentene, and [4]radialene, have been prepared by intramolecular polymerization of macrocyclic polyacetylenes. Two-electron reduction of these cyclic pi-systems with lithium creates interesting anionic species. Structures of the dianions of dimethylenecyclobutene, trimethylenecyclopentene, and [4]radialene are elucidated by X-ray crystallography. Interesting phenomena such as lithium-walk in the dianion of [4]radialene was observed.
The dianion of l, 3, 4, 6, 7, 9-hexasila-1, l, 3, 3, 4, 4, 6, 6, 7, 7, 9, 9-dodecamethyltriindane was planar and exhibited stable triplet esr spectrum at room temperature. Although the ground state was singlet but the singlet-triplet energy difference was only 1 kcal/mole that was the lowest value ever observed.
Several new reactive intermediates such as diamino-substituted silylenes, trimethylsilyl-methyl-substituted disilenes, and hexamethyltetrasila-1, 3-butadiene were generated and reaction modes were examined.
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