Boat conformation of a perhydro-1,3,2-oxazaphosphorine ring containing five-co-ordinate phosphorus: X-ray crystal and molecular structures of 2,2-bis-(p-bromophenoxy)-2-dimethylamino-4,4,5,5-tetrakistrifluoromethyl-1,3,2-dioxaphosph(V)olan and 5-p-bromophenoxy-10-methyl-2,2,3,3-tetrakistrifluoromethyl-1,4,6-trioxa-10-aza-5-phosphaspiro[4.5]decane

Abstract

The preference for the equatorial plane of the lone-pair of nitrogen attached to trigonal bipyramidal phosphorus(V) is demonstrated in the molecular geometries, determined by X-ray crystallography, of 2,2-bis-p-bromophenoxy-2-dimethylamino-4,4,5,5-tetrakistrifluoromethyl-1,3,2-dioxaphosph(V)olan and of 5-p-bromophenoxy-10-methyl-2,2,3,3-tetrakistrifluoromethyl-1,4,6-trioxa-10-aza-5-phosphaspiro[4.5]decane where the perhydro-oxazaphosphorine ring adopts a boat conformation.