Synthesis and solution multinuclear nuclear magnetic resonance studies of homoleptic copper(I) complexes of Group 15 donor ligands

Abstract

The homoleptic complexes [CuL₄]Y (L = PMe₃, PMe₂Ph, PMePh₂, PPh₃, PPh₂H, PPhH₂, AsMe₃, AsMe₂Ph, AsMePh₂, AsPh₃, SbMe₃, SbEt₃ or SbPh₃; Y = PF₆ or BF₄) and [Cu(L–L)₂]Y [L–L = Me₂P(CH₂)₂PMe₂, o-C₆H₄(PMe₂)₂, Ph₂P(CH₂)_nPPh₂(n= 1–4), cis-Ph₂PCHCHPPh₂, o-C₆H₄(PPh₂)₂, o-C₆H₄(AsMe₂)₂, cis-Ph₂AsCHCHAsPh₂, o-C₆H₄(SbMe₂)₂, Me₂Sb(CH₂)₃SbMe₂ or Ph₂Sb(CH₂)₃SbPh₂] have been prepared from [Cu(MeCN)₄]Y and L or L–L. The ⁶³Cu and, where appropriate, ³¹P-{¹H} NMR spectra, have been recorded from CH₂Cl₂ solutions of the complexes over the temperature range 300–175 K, including the first reported ⁶³Cu resonances from arsenic and antimony donor ligand compounds. The effects of ligand size and geometry upon the ⁶³Cu NMR spectra are discussed and typical copper chemical-shift ranges for Group 15 donor ligand compounds established. The structure of [Cu(cis-Ph₂AsCHCHAsPh₂)₂]PF₆ has been established by X-ray crystallography: orthorhombic, space group P2₁2₁2₁, a= 14.775(6), b= 16.991(5), c= 21.027(6)Å, Z= 4. The copper atom is in a distorted tetrahedral environment [Cu–As 2.348(3)–2.358(3)Å].