[1,2-Bis(diphenylphosphino)-1,2-dicarba-closo-dodecaborane-κ²P,P′][7,8-bis(diphenylphosphino)-7,8-dicarba-nido-undecaborato-κ²P,P′]gold(I)–dichloromethane–water (2/1/1)

Abstract

[1,2-Bis(diphenylphosphino)-1,2-dicarbacloso-dodecaborane-j Key indicators: single-crystal X-ray study; T = 150 K; mean (C-C) = 0.010 Å; Hatom completeness 99%; disorder in main residue; R factor = 0.044; wR factor = 0.094; data-to-parameter ratio = 14.8.The title compound, [Au(C 26 H 30 B 10 P 2 )(C 26 H 30 B 9 P 2 )]Á-0.5CH 2 Cl 2 Á0.5H 2 O, contains two independent complex molecules in the asymmetric unit. The gold(I) centres display a distorted tetrahedral geometry. The complex is stablized through weak intramolecular -stacking (CgÁ Á ÁCg = 4.17 Å ) and edge-to-face interactions (HÁ Á ÁCg = 3.21 Å ). Adjacent molecules interact through C-HÁ Á Á (HÁ Á ÁCg = 2.88 Å ) and B-HÁ Á Á (HÁ Á ÁCg = 3.15 Å ) contacts, forming a threedimensional network, with solvent molecules occupying the cavities. One of the phenyl groups was disordered over two sites with occupancy factors of 0.65 and 0.35. Related literatureThe chelating P-donor ligand 1,2-bis(diphenylphosphino)-1,2-dicarba-closo-carborane has been used to prepare 2-, 3-and 4-coordinate complexes of gold(I) (Crespo et al., 1992(Crespo et al., , 1994 AlBaker et al., 1985). Coordination of this ligand has often led to deboronation of the closo-carborane cage to afford the corresponding nido-carborane in polar solvents (Teixidor et al., 1995(Teixidor et al., , 1996. A non-solvated crystal structure of the title compound has been reported previously (Crespo et al., 1997). Facile deboronation of the carborane cage in polar solvents has also been observed when substituents to the cage are electron withdrawing (Shaeck & Kahl, 1999; Ioppolo et al., 2007a,b). In contrast, our group has shown that ligands containing the thermodynamically stable 1,12-carborane cluster do not degrade upon complexation to gold(I) (Ioppolo et al., 2007a,b

Gold: Oxidative Addition to Au(I)

“…The reaction proceeds similarly with the disilane (Ph 2 MeSi) 2 and the ensuing complex 24b (obtained in *40 % yield according to 31 P NMR) displays a very similar 29 Si NMR pattern (δ = 34.5 ppm, d, 2 J SiP = 39.8 Hz). Interestingly, the non-symmetrical disilane Ph 2 MeSi-SiMe 2 Ph is also activated at gold.…”

“…Upon addition of GaCl 3 (1 eq. ), the 31 P NMR signal of (Ph 3 P)AuCl shifted from δ = 33 ppm to δ = 31 ppm. The resulting adduct is stable for hours at −80°C, but rapidly decomposes at higher temperatures.…”

“…1.7 Å vs. about 1.4 Å in benzene) and the rigidity of the cluster allows for precise directional control of both phosphorus atoms and puts their electron lone pairs in a geometry suitable for chelation of a metal center. P-M-P bite angles of approximately 90°with o-carborane-diphosphine ligands were observed for palladium [23,24], platinum [25] and coinage metal complexes [7,[26][27][28][29][30][31].Although o-carborane-diphosphines have been used as ligands for photochemical [32][33][34] or catalytic [35] applications, their coordination chemistry is by far less developed with regard to comparable, simpler diphosphines such as 1,2-bis(phosphino)ethane or 1,2-bis(phosphino)benzene. …”

“…According to 31 P NMR, complex 27 was formed in about 59 % yield along with unidentified byproducts. In addition to the 31 …”

“…In complex 26, the corresponding 29 Si NMR signal appears as a doublet ( 3 J SiP = 8.0 Hz) at δ = −5.5 ppm. Addition of the disilane (PhMe 2 Si) 2 to a 1:1 mixture of complex 26 and GaCl 3 at −80°C resulted in the instantaneous formation of complex 27 (*60 % yield according to 31 P NMR) along with some side products (Scheme 5.5). Complex 27 is thermally unstable and decomposes within hours at −80°C.…”