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 κ2-bonded tris­(pyrazolyl)­borate
ligand. They are ideal for examining the trends involving ethylene
complexes of the group 11 triad. The ethylene 13C NMR resonance
of the [PhB­(3-(C2F5)­Pz)3]­M­(C2H4) adducts in C6D12 appear
at δ 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.