Preparation and properties of fluorenylidene(phenyl)phosphines bearing bulky groups with electron-donating substituents in the ortho position on the phenyl group

Huorenylidene(phenyl)phosphines having bulky substituents with an electron-donating group in the o-position on the phenyl group were prepared and their properties were compared. The prepared materials included 2,4-di-t-butyl-6-methoxyphenyl, 2,4-di-t-butyl-6-(phenoxymethyl)phenyl, 2,4-di-t-butyl-6-(dimethylamino)phenyl, or 2,4-di-t-butyl-6-(2-phenylethyl) phenyl. The diphosphenes and dithioxophosphoranes bearing the 2,4-di-t-butyl-6-(phenoxymethyl)phen-yl group that formed were observed by ³¹PNMR spectroscopy; the effects of the substituent on these multiply bonded phosphorus species are discussed.