Copper(I) complexes supported by a heavily fluorinated bis(pyrazolyl)borate: syntheses and characterization of [H 2B(3,5-(CF 3) 2Pz) 2]CuL (where L = PPh 3, N [tbnd]CCH 3, HC [tbnd]CPh, H 2C [dbnd]CHPh) and {[H 2B(3,5-(CF 3) 2Pz) 2]Cu} 2(1,5-COD)

Abstract

The fluorinated bis(pyrazolyl)borate [H 2B(3,5-(CF 3) 2Pz) 2] − allows the isolation of thermally stable copper(I) complexes containing phosphorus and nitrogen based donors, alkyne and alkene ligands. [H 2B(3,5-(CF 3) 2Pz) 2]Cu(PPh 3), [H 2B(3,5-(CF 3) 2Pz) 2]Cu(NCCH 3) and {[H 2B(3,5-(CF 3) 2Pz) 2]Cu} 2(1,5-COD) were synthesized by using [H 2B(3,5-(CF 3) 2Pz) 2]K, CF 3SO 3Cu, and the appropriate ligand, PPh 3, NCCH 3 or 1,5-COD. [H 2B(3,5-(CF 3) 2Pz) 2]Cu(HC CPh) and [H 2B(3,5-(CF 3) 2Pz) 2]Cu(H 2C CHPh) were obtained by treating [H 2B(3,5-(CF 3) 2Pz) 2]Cu(NCCH 3) with phenylacetylene and styrene, respectively. X-ray data show that [H 2B(3,5-(CF 3) 2Pz) 2]CuL (where L = PPh 3, HC CPh, H 2C CHPh) and {[H 2B(3,5-(CF 3) 2Pz) 2]Cu} 2(1,5-COD) have three-coordinate, trigonal planar copper sites. The bis(pyrazolyl)borate moiety adopts the common boat conformation. The ν C C stretching band of [H 2B(3,5-(CF 3) 2Pz) 2]Cu(PhC CH) was observed at 1927 cm −1. Structural and spectroscopic data of the alkene and alkyne complexes indicate minimal back-bonding from the d 10 copper(I) center.