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  • Author: George Siasios x
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Abstract

The crystal structures of the title compounds P,P-diphenyl-N-methyl-phosphinylthioformamide, [Ph2P(O)C(S)N(H)Me], and P,P-diphenyl-N-phenyl-selenophosphinylthioformamide, [Ph2P(Se)C(S)N(H)Ph], have been determined at room temperature. The pale-yellow crystals of [Ph2P(O)C(S)N(H)Me] are monoclinic, space group P21/c with unit cell dimensions a = 9.663(1), b = 14.073(2), c = 10.775(1) Å, β = 105.78(1)°, Z = 4 and Dx = 1.297 Mg m−3. The green crystals of [Ph2P(Se)C(S)N(H)Ph] are orthorhombic, crystallizing in the Pbca space group with dimensions a = 11.978(1), b = 8.772(5), c = 34.241(4) Å, Z = 8 and Dx = 1.477 Mg m−3. The structures were solved by direct-methods and Patterson methods, respectively and each refined by a full-matrix least-squares procedure to final R = 0.041 using 1474 reflections for [Ph2P(O)C(S)N(H)Me] and R = 0.046 using 1371 reflections for [Ph2P(Se)C(S)N(H)Ph]. The conformation about the C–N bond in [Ph2P(O)C(S)N(H)Me] is Z with important parameters: P = O 1.485(2), P–C 1.843(3), C = S 1.653(3) and C–N 1.313(4) Å. Centrosymmetric molecules associate in the lattice via hydrogen bonding contacts. A similar Z conformation is found in [Ph2P(Se)C(S)N(H)Ph] with important parameters: P = Se 2.108(2), P–C 1.871(7), C = S 1.634(8) and C–N 1.317(9) Å. The analysis of the geometric parameters defining the central chromophore indicate that the P–C bonds are comparatively weak in these phosphorus(V) compounds.

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.

Abstract

The crystal structures of the title compounds P,P-diphenyl-N-phenyl-phosphinylthioformamide ([Ph2P(=O)C(=S)N(H)Ph], LOH) and P,P-diphenyl-N-phenyl-thiophosphinylthioformamide ([Ph2P(=S)C(= S)N(H)Ph], LSH) have been determined at room temperature. Bright yellow crystals of LOH are triclinic, space group P[unk] with unit cell dimensions a = 8.785(1) Å, b = 12.004(2) Å, c = 8.741(1) Å, α = 110.06(1)°, β = 94.63(1)°, γ = 100.82(1)°, Z = 2 and Dx = 1.334 Mg m−3. Yellow crystals of LSH are orthorhombic, crystallizing in the Pbca space group with dimensions a = 11.922(1) Å, b = 8.742(1) Å, c = 34.043(2) Å, Z = 8 and Dx = 1.323 Mg m−3. The structures were solved by direct methods and each refined by a full-matrix least-squares procedure to final R = 0.051 using 2059 reflections for LOH and R = 0.042 using 1325 reflections for LSH. The molecular structures indicate the presence of relatively weak P – C bonds for the central chromophores. This, plus the lack of planarity of the P(Y)C(S)N(H), Y = O or S, moieties suggests little delocalization of π-electron density over the respective chromophores. The structure of LSH is strictly molecular whereas molecules of LOH associate via hydrogen bonds linking the amide H atoms and the O atoms to form centrosymmetric dimers.

Abstract

The crystal structures of the title compounds R3PAu(S2CO-c-C6H11), R = Et, Ph and c-hexyl, have been determined at room temperature. Monoclinic crystals of the R = Et compound have space group C2/c with unit cell dimensions a = 26.754(4) Å, b = 7.264(1) Å, c = 18.928(3) Å, β = 102.04(1)°, Z = 8 and Dx = 1.811 Mg m−3. Crystals of the R = Ph structure are triclinic with space group P[unk] and unit cell dimensions a = 11.372(2) Å, b = 13.053(6) Å, c = 9.488(3) Å; α = 109.45(3)°, β = 99.19(2)°, γ = 106.28(3)°, Z = 2 and Dx = 1.722 Mg m−3. The R = c-hexyl compound crystallizes in the orthorhombic space group P212121 with unit cell dimensions a = 8.121(1) Å, b = 11.108(4) Å, c = 30.212(5) Å,Z = 4 and Dx = 1.591 Mg m−3. The structures were refined by a full-matrix least-squares procedure on 1908 reflections to final R = 0.039 for the R = Et compound, 3664 reflections and R = 0.055 for R = Ph and 1501 reflections and R = 0.040 for R = c-hexyl. The Au atom in each of the structures is linearly coordinated by the S atom, derived from a monodentate xanthate ligand, and the P atom. Different orientations of the xanthate ligands results in two structural forms. For the R = Et and Ph compounds the O atom is in close proximity of the Au atom whereas for the R = c-hexyl compound the S atom is orientated towards the Au atom. The different structures are rationalized in terms of the steric demands of the phosphine ligands. A close Au … Au interaction of 3.120(1) Å is found in the R = Et compound; no such contacts are observed in the R = Ph and c-hexyl structures.