97092-71-2Relevant academic research and scientific papers
Synthesis and characterization of [Et4N][M(CO)5SR] and [Et4N]2[M2(CO)8(SR)2] complexes (M = Cr, Mo, W). Ligand substitution reactions and X-ray crystal structure of [Et4N]2[W2(CO)8(SPh)2]
Darensbourg, Donald J.,Sanchez, Kathryn M.,Reibenspies, Joe
, p. 3636 - 3643 (2008/10/08)
A series of complexes, [Et4N][M(CO)5SR] (M = Cr, Mo, W; R = H, Ph), have been synthesized and characterized by 1H and 13C NMR and IR spectroscopies. Gentle heating causes these complexes to lose a carbonyl ligand, yielding the doubly bridged sulfur dimers M2(CO)8(μ-SR)22-. The X-ray crystal structure of [Et4N]2[W2(CO)8(SPh)2] has been determined. The complex crystallizes in the triclinic space group P1 with unit cell parameters a = 9.8664 (17) A?, b = 9.8566 (22) A?, c = 11.8270 (26) A?, α = 65.790 (16)°, β = 81.710 (16)°, γ = 82.000 (16)°, V = 1034.0 (4) A?3, and Z = 1. Both mono- and dinuclear metal complexes readily react with phosphorus donor ligands to afford the carbon monoxide substituted complexes cis-M(CO)4(P)(SR)- (P = PMe3, P(OMe)3, PPh3). In addition, the dimers react with 1 atm of carbon monoxide to re-form the mononuclear species M(CO)5SR- in quantitative yields. Unsuccessful attempts to insert CO2, COS, or CS2 into the M-SR bond in the M(CO)5SR- derivatives are noted.
Two-electron transfer accompanied by metal-metal bond formation. Synthesis and electrochemistry of dinuclear molybdenum and tungsten carbonyl thiolates
Smith, Doris A.,Zhuang, Botao,Newton, William E.,McDonald, John W.,Schultz, Franklin A.
, p. 2524 - 2531 (2008/10/08)
The binuclear, thiolate-bridged complexes [Et4N]2[M2(CO)8(SR)2] (M = Mo, W; R = Ph, t-Bu, Bz) (1), are prepared by refluxing M(CO)6 with [Et4N]SR in acetonitrile. On the basis of analytical, spectroscopic, and conductometric data, they are characterized as 2:1 electrolytes with the dinuclear dianions consisting of two metal(0)-(CO)4 fragments bridged by two μ-SR moieties. The complexes are converted to the corresponding MI2 dimers, M2(CO)8(SR)2 (2), by two-electron electrochemical oxidation (in a single step) (eq i) or treatment with a mild chemical oxidant, to the solvolyzed MI2 dimers, M2(CO)6(MeCN)2(SR)2 (3), by [M2(CO)8(SR)2]2- ? [M2(CO)8(SR)2] + 2e- (i) oxidation in acetonitrile, and to the monomeric M0 species, [M(CO)5(SR)]- (4) (for M = Mo, R = Ph, t-Bu), by treatment with excess CO. Interconversion of 1-4 by means of redox, solvolysis, and carbonylation reactions and the influence of the solvolysis and carbonylation reactions on electrode reactions (eq i) are described. Oxidation of the M02 to the MI2 dimers is accompanied by formation of a single metal-metal bond and significant rearrangement within the M2(SR)2 core. These changes apparently supply the driving force that enables two-electron transfer to occur in a single step. Comparisons with structurally analogous compounds indicate that contractions of ～1.0 A? in the M-M bond distance and of ～25° in the M-S-M bridge angle accompany M02 → MI2 oxidation. Despite these large displacements in nuclear coordinates, electrode reaction i exhibits Nernstian two-electron behavior by cyclic voltammetry at 0.1 V s-1. This kinetically facile behavior suggests that the nuclear rearrangement involved in conversion of [M2(CO)8(SR)2]2- to M2(CO)8(SR)2 is concerted in such a way that a low activation energy barrier is presented to electron transfer.
