Isolable Ethylene Complexes of Copper(I), Silver(I), and Gold(I) Supported by Fluorinated Scorpionates [HB{3‐(CF3),5‐(CH3)Pz}3]– and [HB{3‐(CF3),5‐(Ph)Pz}3]–

The group 11 metal adducts [HB{3-(CF3),5-(CH3)Pz}3]M(C2H4) (M = Au, Ag, and Cu; Pz = pyrazolyl) have been synthesized via a metathesis process using [HB{3-(CF3),5-(CH3)Pz}3]Na and CF3SO3Cu, CF3SO3Ag, AuCl and ethylene. The related [HB{3-(CF3),5-(Ph)Pz}3]Ag(C2H4) has also been synthesized using [HB{3-(CF3),5-(Ph)Pz}3]Na(THF), CF3SO3Ag and ethylene. These group 11 metal ethylene complexes are white solids and form colorless crystals. They have been characterized by NMR spectroscopy and X-ray crystallography. The gold-ethylene adduct [HB{3-(CF3),5-(CH3)Pz}3]Au(C2H4) shows large upfield NMR shifts of the ethylene proton and carbon signals relative to the corresponding peaks of the free ethylene, indicating relatively high Auethylene backbonding. NMR chemical shift data suggest that the silver complexes of both the tris(pyrazolyl)borate ligands [HB{3-(CF3),5-(CH3)Pz}3]– and [HB{3-(CF3),5-(Ph)Pz}3]– exhibit the weakest interaction with ethylene as compared to the respective copper and gold complexes. X-ray crystal structures reveal that the gold atom in [HB{3-(CF3),5-(CH3)Pz}3]Au(C2H4) binds to scorpionate in κ2-fashion while the related silver adduct features a κ3-bonded scorpionate. [HB{3-(CF3),5-(CH3)Pz}3]Cu(C2H4) has a scorpionate that binds to copper with two short Cu–N bonds and one long Cu–N distance.