Title

Unusual Phosphorus−Phosphorus Double Bond Contraction Upon Mono- and Di-auration of A Diphosphene

Document Type

Article

Publication Date

7-29-2009

Publication Title

Journal of The American Chemical Society

Abstract

The diphosphene Mes*P═Mes* (Mes* = 2,4,6-tri-tert-butylphenyl; 1) reacted with 1 or 2 equiv of Au(tht)Cl (tht = tetrahydrothiophene) to produce the stable monoaurated adduct Mes*{AuCl}P═PMes* (2) or diaurated adduct Mes*{AuCl}P═P{AuCl}Mes* (3) respectively. The products were characterized by X-ray crystallography, UV−visible, IR, Raman, and multinuclear NMR spectroscopies, as well as by density functional theory calculations. The crystallographic and Raman spectroscopic data provide physical evidence that the P═P bond grows shorter and increases in strength upon auration; these observations are further examined by DFT calculations for a series of model compounds CH3{AuCl}nP═P{AuCl}n′CH3 1′−3′ (n, n′ = 0 or 1). Compounds 1−3 represent a rare series of crystallographically characterized diphosphenes bearing zero, one, or two AuCl units on each phosphorus atom, allowing for a systematic analysis of the impact of Lewis acids on the phosphorus−phosphorus double bond.

Comments

We thank NSF for support (CHE-0202040 and CHE-0748982 to J.D.P., and CHE-0749086 to T.G.G.) and for funds to purchase the single crystal X-ray diffractometer used in this study (CHE 0541766), and for Dr. M. C. Simpson (University of Auckland, NZ) for helpful comments.

DOI

10.1021/ja900813v

Volume

131

Issue

29