Structure, Bonding, and Dynamics of Several Palladium η3-Allyl Carbene Complexes

Abstract

A series of Pd-allyl carbene complexes, [PdX(η3-C3H5)(IPr)], 1 (X = a, Cl−, b, Br−, c, I−, d, N3−, e, NCO−, f, SCN−, g, CN−, h, OAc−, i, OTf−, j, 4-Me-pyridine), have been studied by one- and two-dimensional NMR techniques. 13C, 1H, and phase-sensitive NOE NMR studies on these relatively simple complexes reveal that (a) the trans influence of the carbene carbon in 1 seems to be smaller than that found for PPh3 and other P-donor ligands, (b) the selective η3−η1 opening of the allyl is under electronic control, and (c) the rates of η3−η1 allyl isomerization depend on the X ligand. The solid-state structure of 1c is reported, as well as selected 15N chemical shift data for the coordinated carbene ligand.