Synthesis and physicochemical properties of stable 1,3-diphosphacyclobutane-2,4-diyls bearing sulfanyl groups

摘要

A cyclic phosphaallyl anion generated from a phosphorus-carbon triple bond (phos-phaalkyne) was allowed to react with dimethyl- and di-p-tolyl disulfide to afford the corresponding l,3-diphosphacyclobutane-2,4-diyls bearing the sulfanyl substituent on phosphorus. The sulfanyl-bearing P-heterocyclic biradicals showed high stability permitting easy handling under ambient conditions. UV-vis spectra and electrochemical properties of the compounds indicated that the sulfanyl groups behave as electron-withdrawing groups to affect electronic properties of the cyclic biradical moiety. X-ray analysis of the p-tolylsulfanyl derivative indicated that the sulfanyl group causes no significant modification in the metric parameters around the central 4-membred biradical skeleton.