The Synthesis, Structure, and Chemistry of 10-pn-3 Systems: Tricoordinate Hypervalent Pnictogen Compounds

A set of previously unknown tricoordinate hypervalent pnictogen compounds, 10-Pn-3 ADPnO, has been synthesized. The chemistry of these systems has been studied. Reactions with alcohols, a-dicarbonyl compounds, halogens, transition metals, protic acids, and acetylenes are among the chemistry described. In general, it was found that 10-As-3 ADAsO and 10-Sb-3 ADSbO systems behave similarly and offer different chemistry from that of the 10-P-3 ADPO system. Among these unusual reactions is a novel C-C bond-forming reaction with hexafluoro-2-butyne. The electronic structure of these systems has been considered in light of preliminary ab initio molecular orbital calculations. The cyclic voltammetry data on the 10-Pn-3 ADPnO systems have been measured and are in accord with theoretical expectations. X-ray structures on a wide variety of derivatives provide insight into the chemistry of these systems. Phosphorus compounds with coordination numbers ranging from 2 to 6 have been characterized, and a trend is observed for³¹P-¹⁵N coupling constants and phosphorus coordination number.