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Abstract:A general approach to the family of completely spirocyclopropanated macrocyclic polydiacetylenes, that is, cyclic dehydrooligomers of 1,l -diethynylcyclopropane 4, is reported. The characterized examples of these "exploding" [nlrotanes are for n = 5, 6, 7, 8, 9, 10, and 12. X-ray crystal structure analyses for the hydrocarbons with n = 5, 6, 7, and 8 disclose a strong electronic interaction between the cyclopropane and the acetylene units leading to a significant shortening of the distal and lengthening of the proximal cyclopropane bonds. While the five-sided compound 18 can occur as a planar or envelope-shaped molecule, depending on the solvent from which crystals are grown,

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1H-Cyclopropa[b]naphthalene is converted into novel polar olefins 15−19 via reaction of the 1,1-disilyl with anthrone-like ketones. The alkenes so formed are crystalline, polar compounds that range in color from yellow to magenta. Solutions of the 10,10-dimethylanthrylidene 15, the xanthenylidene 16, and N-methylacrydinylidene 18 fluoresce; parent anthrone 19 likely phosphoresces. X-ray crystal structure determinations are reported for 15, 18, and the thioxanthenylidene 17. Theoretical studies using ab initio calculations at the HF/6-31G* level have been performed to provide assessments of the structures, charge distributions, and dipole moments of 15−19.