Structurally Similar, Thermally Stable Copper(I), Silver(I), and Gold(I) Ethylene Complexes Supported by a Fluorinated Scorpionate

Treatment of Li[PhBH3] with excess 3-(C2F5)PzH led to the B-phenylated tris(pyrazolyl)borate ligand as its lithium salt [PhB(3-(C2F5)Pz)(3)]Li. This ligand enabled the isolation of thermally stable group 11 metal ethylene adducts [PhB(3-(C2F5)Pz)(3)]M(C2H4) (M = Au, Ag, Cu). They were characterized by spectroscopy and by X-ray crystallography. These ethylene adducts are structurally similar and feature three-coordinate trigonal-planar metal sites and a kappa(2)-bonded tris(pyrazolyl)borate ligand. They are ideal for examining the trends involving ethylene complexes of the group 11 triad. The ethylene C-13 NMR resonance of the [PhB(3-(C2F5)Pz)(3)]M(C2H4) adducts in C6D12 appear at delta 58.9, 101.6, and 85.5 ppm, respectively, for M = Au, Ag, Cu. The M-C and M-N bond distances are largest in the silver complex and smallest in the copper complex.