Structural and spectroscopic studies of three-coordinate copper(I) supported by bis(phosphino)borate ligands

The bis(phosphino)borates [(p'BuPh)(2)B(CH2PPh2)(2)][ASN] (1[ASN]; ASN = 5-azonia-spiro[4.4]nonane), [Ph2B(CH2P'Pr-2)(2)]-Li(THF)(2) (2[Li]), and [(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)](-) (3[Li] and 3[Tl]) react with copper(I) reagents to generate anionic and neutral complexes. Reaction of 1 [ASN] with CuI provides the 1:1 adduct [[(p-'BuPh)(2)B(CH2PPh2)(2)]CuI][ASN] (4). CuCl reacts with 3[Li] in THF to afford [[(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)]CuCl][Li(THF)(4)] (5), along with a minor byproduct, the three-coordinate bis(phosphine) adduct {(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)]CuCl (6). An analogous neutral complex, {PhB(CH2P'Bu-2)(2)]CuCl (7), can be synthesized directly by reacting CuCl with the neutral phosphino borane PhB(CH2P'Bu-2)(2). Reaction of the substituted copper(l) halide Me2S (.) CuBr with 3[Tl] provides the anionic dimer complex [{[(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)]Cu}(2)(mu-Br)]Tl (8). The neutral solvent adducts [Ph2B(CH2P'Pr-2)(2)]Cu(NCCH3) (9) and [(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)]Cu(NCCH3) (10) are prepared by the reactions between [Cu(CH3CN)(4)][PF6] and 2[Li] or 3[Li], respectively. Neutral 10 is a useful precursor to several other neutral species via substitution of the labile acetonitrile ligand, including [(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)]Cu(PMe2Ph)(11), [(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)]-Cu(S=PMe3) (12), [(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)] Cu(2,6-lutidine) (13), and [(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)]Cu(CN'Bu) (14). Attempts to isolate a neutral monocarbonyl adduct, [(3,5-Me2Ph)(2)B(CH2P'Bu-2)(2)]Cu(CO) (15), are frustrated by the high lability of the CO ligand. The solid-state crystal structures of complexes 6, 8, 9, 10, and 11 have been determined and are described. (C) 2004 Elsevier Ltd. All rights reserved.