Synthesis, spectroscopic characterization, and structural systematics of new triorganophosphinecopper(I) poly(pyrazol-1-yl)borate complexes

Abstract

Mono- and bis-(trialkyl- and triaryl-phosphine)copper(I) derivatives containing anionic bis-, tris- and tetrakis-(pyrazol-1-yl)borates were prepared from CuCl, [CuBr(Me₂S)] or [Cu(C₆H₆)_0.5(O₃SCF₃)]₂, R₃P (R = phenyl, benzyl, cyclohexyl, o-, m-, or p-tolyl) or R′Ph₂P (R′ = methyl or ethyl), and M[H_nB(pz)_4-n] (M = Na or K, n = 0, 1 or 2; Hpz = pyrazole in general; in detail, pyrazole (Hpz), 3,5-dimethylpyrazole (Hm₂pz), 3-methylpyrazole (Hmpz)) and characterized through analytical and spectral measurements (IR, ¹H and ³¹P NMR). The same complexes can be obtained also from the reaction of [Cu(O₂NO)(PR₃)₂] with M[H_nB(pz)_4-n]. These air-stable compounds are non-electrolytes in CH₂Cl₂ and in acetone, in which they slowly decompose even with the strict exclusion of oxygen. Low-temperature single crystal structural characterizations were undertaken for several of them. The structurally authenticated arrays fall into three different types: (a) [Cu((pz)₂BH_n(pz)_2-n)(PR₃)₂] with a four-co-ordinate P₂Cu(N₂) co-ordination sphere, (b) [Cu((pz)₃BH)(PR₃)] with a four-co-ordinate PCu(N₃) co-ordination sphere, (c) [Cu((pz)₂BH_n(pz)_2-n)(PR₃)] with a three-co-ordinate PCu(N₂) co-ordination sphere.