Synthesis, reactivity and structures of diethyldithiophosphate molybdenum complexes: crystal structures of [Mo{η2-S2P(OEt2)}2(PhCCPh)2] and [Mo(η3-C3H5){η1-S2P(OEt2)}(Phen)(CO)2]

Treatment of [Mo(CH3CN)(η3-C3H5)(CO)2{η2-S2P(OEt2)}] (1) with diphenylacetylene, PhCCPh, in refluxing dichloromethane produced the bis(diphenylacetylene) complex [Mo{η2-S2P(OEt2)}2(PhCCPh)2] (2). No similar bisalkyne product was obtained in the reaction of complexes [Mo(η3-C3H5)(CO)2(η2-LL)(X)] (LL, X=Et2NCS2; C4H8NCS2; C5H10NCS2; H2BPz2; C5H7O2, CH3CN (3)) and PhCCPh, respectively, even under extreme experimental conditions. Complex [Mo(η3-C3H5){η1-S2P(OEt2)}(Phen)(CO)2] (4) are accessible by the reactions of 1 and phenanthroline at room temperature. The single crystal structures of complexes 2 and 4 were determined by X-ray diffraction analyses. Crystal data for 2: space group, P with a=10.874(4), b=11.745(4), c=16.052(11) Å, α=90.44(4), β=94.45(4), γ=108.90(3)°, V=1932.6(16) Å3, Z=2. The structure was refined to R=0.029 and Rw=0.032. Crystal data for 4: space group, P with a=7.9518(16), b=10.104(2), c=16.107(3) Å, α=83.91(2), β=81.63(2), γ=66.55(2)°, V=1172.9(4) Å3, Z=2. The structure was refined to R=0.062 and Rw=0.154. The coordination geometry about the molybdenum in 2 may be considered to be octahedral, with four sulfur atoms of the diethyldithiophosphato ligands and the two cis and parallel diphenylacetylene ligands. In complex 4, pseudo-octahedral surrounding of the metal ion is formed by the coordination of two carbonyl ligands, of a phenanthroline ligand lying in the square plane of the molybdenum atom, and of a symmetrical η3-allyl group and a η1-diethyldithiophosphato ligand lying trans to one another in apical positions above and below the plane. No intramolecular trigonal twist behavior was found in solution state from 183 to 298 K of 4.