1-Phosphino-1,3-butadiene Derivatives Incorporated with Dibenzobarrelene Skeleton: Synthesis and Photophysical Properties

An intramolecular [4+2] cycloaddition of 1-(9-anthrylchlorophosphino)-1,4-diphenylbut-1-en-3-yne produced the 1-(chlorophosphino)-1,4-diphenyl-1,3-butadiene derivative incorporated with a dibenzobarrelene skeleton, the following reactions of which gave the corresponding secondary phosphine oxide and phenylphosphine sulfide. The secondary phosphine oxide was deprotonated with butyllithium followed by treatment with methyl iodide to give methylphosphine oxide. The phenylphosphine sulfide was desulfurized with P(NMe2)3to give the corresponding phenylphosphine, which was converted to the oxide and selenide and AuCl and BH3complexes. Their structures were determined by X-ray crystallography. These compounds show blue fluorescence in solution (FF= 0.49–0.86) and the solid state (FF= 0.02–0.72) in a narrow range (?em= 442–463 nm) except the phenylphosphine selenide with a low fluorescence efficiency. Their photophysical properties were considered theoretically. The secondary phosphine oxide and the methylphosphine oxide were optically resolved by means of HPLC equipped with a chiral column, and the chiroptical properties were investigated to show weak circular polarized luminescence (CPL) of |gem| = 2.8–8.8 × 10-4.Intramolecular [4+2] cycloaddition of 1-(9-anthrylchlorophosphino)-1,4-diphenylbut-1-en-3-yne produced the 1-(chlorophosphino)-1,4-diphenyl-1,3-butadiene incorporated with a dibenzobarrelene, from which the corresponding secondary phosphine oxide, methylphosphine oxide, phenylphosphine and the chalcogenides, and AuCl and BH3complexes were synthesized. They show blue fluorescence in solution and the solid state. The optically resolved secondary phosphine oxide and the methylphosphine oxide showed CPL of |gem| = 2.8–8.8 × 10-4.