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

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[HnB(pz)(4-n)] (M = Na or K, n = 0, 1 or 2; Hpz = pyrazole in general; in detail, pyrazole (Hpz), 3,5-dimethylpyrazole (Hm(2)pz), 3-methylpyrazole (Hmpz)) and characterized through analytical and spectral measurements (IR, H-1 and P-31 NMR). The same complexes can be obtained also from the reaction of [Cu(O2NO)(PR3)(2)] with M[HnB(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)(2)BHn(pz)(2-n))(PR3)(2)] with a four-co-ordinate P2Cu(N-2) co-ordination sphere, (b) [Cu((pz)(3)BH)(PR3)] with a four-co-ordinate PCu(N-3) co-ordination sphere, (c) [Cu((pz)(2)BHn(pz)(2-n))(PR3)] with a three-co-ordinate PCu(N-2) co-ordination sphere.