Synthesis, reactivity and structures of diethyldithiophosphate molybdenum complexes: crystal structures of [Mo{η^2-S2P(OEt2)}2(PhC≡CPh)2]and[Mo(η^3-C3H5){η^1-S2P(OEt2)}(Phen)(CO)2]

Treatment of [Mo(CH3CN)(h3-C3H5)(CO)2{h2-S2P(OEt2)}] (1) with diphenylacetylene, PhC/CPh, in refluxing dichloromethane
produced the bis(diphenylacetylene) complex [Mo{h2-S2P(OEt2)}2(PhC/CPh)2] (2). No similar bisalkyne product was obtained in
the reaction of complexes [Mo(h3-C3H5)(CO)2(h2-LL)(X)] (LL, X/Et2NCS2; C4H8NCS2; C5H10NCS2; H2BPz2; C5H7O2, CH3CN
(3)) & PhC/CPh, respectively, even under extreme experimental conditions. Complex [Mo(h3-C3H5){h1-S2P(OEt2)}(Phen)(CO)2]
(4) are accessible by the reactions of 1 & phenanthroline at room temperature. The single crystal structures of complexes 2 & 4
were determined by X-ray diffraction analyses. Crystal data for 2: space group, P/¯1 with a/10.874(4), b/11.745(4), c/16.052(11)
A ° , a/90.44(4), b/94.45(4), g/108.90(3)8, V/1932.6(16) A ° 3, Z/2. The structure was refined to R/0.029 & Rw/0.032. Crystal data for 4: space group, P/¯1 with a/7.9518(16), b/10.104(2), c/16.107(3) A ° , a/83.91(2), b/81.63(2), g/66.55(2)8,
V/1172.9(4) A° 3, Z/2. The structure was refined to R/0.062 & 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 & the two cis & 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, & of a symmetrical h3-allyl group & a h1-diethyldithiophosphato ligand lying trans to one another in apical positions above & below the plane. No intramolecular trigonal twist behavior was found in solution state from 183 to 298 K of 4.