Partially fluorinated Scorpionate [HB(3-(CF3),5-(Ph)Pz)3]− as a supporting ligand for silver(I)-benzene, -carbonyl, and -PPh3 complexes

Abstract

The benzene, CO, and PPh3 adducts [HB(3-(CF3),5-(Ph)Pz)3]AgL (L=C6H6, CO, or PPh3) have been synthesized by a metathesis process using [HB(3-(CF3),5-(Ph)Pz)3]Na(THF), CF3SO3Ag, and the corresponding co-ligands. These silver(I) adducts have been characterized by NMR spectroscopy, and by X-ray crystallography. In all cases the Scorpionate is bound to silver in typical κ3-fashion. The X-ray crystallographic data of [HB(3-(CF3),5-(Ph)Pz)3]Ag(η2-C6H6) show that it has a η2-bound benzene molecule. NMR data point to fluxional behavior in solution. The 13C NMR resonance corresponding to the CO moiety of [HB(3-(CF3),5-(Ph)Pz)3]Ag(CO) appears as a single peak at δ 177.4ppm and the ν¯co is observed at 2148cm−1. These values indicate the presence of a fairly Lewis acidic silver atom in [HB(3-(CF3),5-(Ph)Pz)3]Ag(CO) and significantly diminished Ag→CO π-backbonding. Interesting coupling is observed in the solution 19F and 31P NMR spectra of the Ag(I) adduct [HB(3-(CF3),5-(Ph)Pz)3]Ag(PPh3). A detailed analysis of the spectral and structural features of these complexes has been described herein.