Crystal structures of tricyclohexylphosphinegold(I) O-alkyldithiocarbonates: (c-C6H11)3PAu(S2COR), R = Et, nPr and iPr

Abstract

Abstract The crystal structures of the title compounds (c-C6H11)3PAu(S2COR), R = Et, nPr and iPr have been determined at room temperature. Triclinic crystals of the R = Et compound have space group P[unk] with unit cell dimensions a = 11.134(4), b = 11.826(4), c = 10.292(4) Å, α = 92.71(3), β = 102.50(4), γ = 64.26(4)°, Z = 2 and D x = 1.671 Mg m−3. Crystals of the R = nPr compound are monoclinic with space group P21/c, and unit cell dimensions a = 12.334(1), b = 21.259(2), c = 10.300(1) Å; β = 113.33(1)°, Z = 4 and D x = 1.641 Mg m−3. The R = iPr derivative also crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 10.974(5), b = 18.313(4), c = 12.754(2) Å, β = 91.40(2)°, Z = 4, D x = 1.588 Mg m−3. The structures were refined by a full-matrix least-squares procedure on 3826 reflections to final R = 0.048 for the R = Et compound, 2982 reflections and R = 0.050 for R = nPr and 3185 reflections and R = 0.060 for R = iPr. The gold atom in each structure exists in an essentially linear geometry defined by the P atom of the (c-C6H11)3P ligand and the S atom of the dithiocarbonate ligand. For the R = Et and nPr compounds the dithiocarbonate ligand is orientated so as to place the O atom in close proximity of the Au atom whereas in the R = iPr derivative the non-coordinating S atom is directed towards the Au atom; these differences are rationalized in terms of the steric demands of the ligands.