Syntheses, x-ray crystal structures, and solution behavior of cationic, two-coordinate gold(I) η²-diene complexes

A family of cationic gold p-diene complexes of the form {[P(t-Bu) 2o-biphenyl]Au(η2-diene)}+SbF6- were isolated in >80% yield from reaction of various dienes with a mixture of [P(t-Bu)2o-biphenyl]AuCl and AgSbF6 and were characterized by spectroscopy and, in four cases, by X-ray crystallography. Solution and solid-state analysis of these complexes established selective binding of gold to the less substituted CdC bond of the diene in the case of dienes that possessed differentially substituted CdC bonds. 13C NMR analysis and evaluation of the relative binding affinities of substituted dienes point to a bonding model in which the gold-alkene interaction is stabilized via donation of electron density from the uncomplexed CdC bond to the complexed CdC bond of the diene. Variable-temperature NMR analysis of gold p-diene complexes revealed fluxional behavior consistent with facile (δG = 9.6-11.9 kcal mol-1) intramolecular exchange of the complexed and uncomplexed CdC bonds of the diene ligand. © 2011 American Chemical Society.

Duke Scholars

Author Ross A. Widenhoefer Chemistry