CRYSTAL-STRUCTURES OF TRICYCLOHEXYLPHOSPHINEGOLD(I) O-ALKYLDITHIOCARBONATES - (C-C6H11)3PAU(S2COR),R = ET, (N)PR AND (I)PR

The crystal structures of the title compounds (c-C6H11)3-PAu(S2COR), R = Et, (n)Pr and (i)Pr have been determined at room temperature. Tricl inic crystals of the R = Et compound have space group P1BAR with unit cell dimensions a = 11.134(4), b = 11.826(4), c = 10.292(4) angstrom, alpha = 92.71(3), beta = 102.50(4), gamma = 64.26(4)-degrees, Z = 2 an d D(x) = 1.671 Mg m-3. Crystals of the R = (n)Pr compound are monoclin ic with space group P2(1)/c, and unit cell dimensions a = 12.334(1), b = 21.259(2), c = 10.300(1) angstrom; beta = 113.33(1)-degrees, Z = 4 and D(x) = 1.641 Mg m-3. The R = (i)Pr derivative also crystallizes in the monoclinic space group P2(1)/c, with unit cell dimensions a = 10. 974(5), b = 18.313(4), c = 12.754(2) angstrom, beta = 91.40(2)-degrees , Z = 4, D(x) = 1.588 Mg m-3. The structures were refined by a full-ma trix least-squares procedure on 3826 reflections to final R = 0.048 fo r the R = Et compound, 2982 reflections and R = 0.050 for R = (n)Pr an d 3185 reflections and R = 0.060 for R = (i)Pr. The gold atom in each structure exists in an essentially linear geometry defined by the P at om of the (c-C6H11)3P ligand and the S atom of the dithiocarbonate lig and. For the R = Et and (n)Pr compounds the dithiocarbonate ligand is orientated so as to place the O atom in close proximity of the Au atom whereas in the R = (i)Pr derivative the non-coordinating S atom is di rected towards the Au atom; these differences are rationalized in term s of the steric demands of the ligands.