SYNTHESES AND CHARACTERIZATION OF GOLD(I) AND PLATINUM(II) COMPLEXES CONTAINING TRIS(2-CYANOETHYL)PHOSPHINE - X-RAY CRYSTAL-STRUCTURES OF [(CEP)2AU]CL, CIS-(CEP)(ET2S)PTCL2, AND TRANS-(CEP)2PTCL2

The following gold(I) and platinum(II) complexes of tris(2-cyanoethyl)phosphine, CEP, have been synthesized: (CEP)AuCl (1), [(CEP)2Au]Cl (2), cis-(CEP)(Et2S)PtCl2 (3), trans-(CEP)2PtCl2 (4). The structures of 2-4 are reported here. Compound 2 crystallized in the trigonal (hexagonal) space group R3c (No. 167) with unit cell a = 12.216(2) angstrom, c = 25.88 5(7) angstrom, gamma = 120-degrees, V = 3345(1) angstrom3, and Z = 6. The Au(I) center is encapsulated by six CN groups of two P(CH2CH2CN)3 ligands. The cation structure has S6 point group symmetry. Refinement of 780 reflections and 44 parameters yielded R = 0.0256 and R(w) = 0.0268. The Au(I)-P distance is 2.314(2) angstrom, and the average nonbonding Au(I)...N distance for CN groups is 3.579(3) angstrom. Compound 3 crystallized in the monoclinic space group P2(1)/c (No. 14) with unit cell a = 12.029(8) angstrom, b = 7.432(5) angstrom, c = 21.43 (2), beta = 93.17(6)degrees, V = 1911(2) angstrom3, and Z = 4. Refinement of 2888 reflections and 195 parameters yielded R = 0.0474 and R(w) = 0.0348. The average Pt-Cl distance is 2.353(5) angstrom, the Pt-P distance is 2.250(5) angstrom, and the Pt-S distance is 2.298(5) angstrom. Compound 4 crystallized in the orthorhombic space group Pcab (No. 61) with unit cell a = 14.14(1) angstrom, b = 4.17(1) angstrom, c = 18.87(2) angstrom, V = 2445 (4) angstrom3, and Z = 4. Refinement of 1847 reflections and 133 parameters yielded R = 0.0400 and R(w) = 0.0384. Both CEP ligands in [(CEP)2Au]Cl encapsulate the gold(I) atom while in (CEP)2PtCl2 the ligands form an inverted ''umbrella'' relative to Pt(II). The Pt-Cl distance is 2.317(3) angstrom, and the Pt-P distance is 2.312(3) angstrom. Hydrolysis of 2 at 120-degrees-C in the presence of H2SO4/H2O gives ClAu[P(CH2CH2COOH)3]2.