Structural and solid state 31P NMR studies of the four-coordinate copper(i) complexes [Cu(PPh3)3X] and [Cu(PPh3)3(CH3CN)]X

Dalton Transactions Pub Date: 2005-06-27 DOI: 10.1039/B505200A

Abstract

The tris(triphenylphosphine)copper(I) complexes [(PPh3)3CuX] for X = Cl (1), Br (2), I (3), ClO4 (4), BF4 (5), [(PPh3)3CuCl]·CH3CN (1a), [Cu(PPh3)3(CH3CN)]X for X = ClO4 (6), BF4 (7), and [Cu(PPh3)3(CH3CN)]X·CH3CN for X = SiF5 (8), PF6 (9) have been studied by solid state 31P CP/MAS NMR spectroscopy together with single crystal X-ray diffraction for compounds (6)–(9), the latter completing the availability of crystal structure data for the series. Compounds (1)–(5) form an isomorphous series in space group P3 (a ～ 19, c ～ 11 ?) with three independent molecules in the unit cell, all disposed about 3-fold symmetry axes. Average values (with estimated standard deviations) for the P–Cu–P, P–Cu–X bond angles and Cu–P bond lengths in compounds (1)–(3) are 110.1(6)°, 108.8(6)° and 2.354(8) ? and 115.2(6)°, 102.8(9)° and 2.306(9) ? for compounds (4) and (5). For the acetonitrile solvated compound (1a), the corresponding parameters are 115(4)°, 103(3)° and 2.309(3) ?. The solid state 31P CP/MAS NMR quadrupole distortion parameters, dνCu, for (1)–(3) and (1a) are all less than 1 × 109 Hz2, despite the changes in donor properties of the halide in (1)–(3), and the coordination geometry of the P3CuX core in (1a). Change of anion to ClO4? and BF4? in compounds (4) and (5) results in a significant increase of dνCu to 4.4–5.2 109 Hz2 and 5.2–6.0 × 109 Hz2, respectively. Compounds (6) and (7) crystallise as isomorphous [Cu(PPh3)3(CH3CN)]X salts in space group Pbca, (a ～ 17.6, b ～22.3, c ～24.2 ?), while compounds (8) and (9) crystallize as isomorphous acetonitrile solvated salts [Cu(PPh3)3(CH3CN)]X·CH3CN in space group P[1 with combining macron] (a ～ 10.5, b ～ 13.0, c ～19.5 ?, α ～ 104, β ～ 104, γ ～ 94°). The P3CuN angular geometries in all four compounds are distorted from tetrahedral symmetry with average P–Cu–P, P–Cu–N angles and Cu–P bond lengths of 115(4)°, 103(4)° and 2.32(1) ?, with dνCu ranging between 1.3 and 2.5 × 109 Hz2. The solid state 29Si CP/MAS NMR spectrum of the pentafluorosilicate anion in compound (8) is also reported, affording 1J(29Si, 19F) = 146 Hz.

Graphical abstract: Structural and solid state 31P NMR studies of the four-coordinate copper(i) complexes [Cu(PPh3)3X] and [Cu(PPh3)3(CH3CN)]X
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