The crystal and molecular structure of tetraphenylarsonium Tetrakis(benzenethiolato)oxomolybdate(V)

Abstract

Crystals of the title compound, Ph4As+ [MoO(SPh)4]-, belong to the triclinic space group Pī with cell dimensions a 12.623(8), b 14.295(7), c 14.301(9) Ǻ, α 94.43(4), β 111.43(5), γ 65.70(4)° and Z2. The structure has been refined with diffractometer data measured with Mo Kα radiation to give a conventional R factor of 0.056 for 3215 unique terms. The Mo, As, S and O atoms were refined with anisotropic temperature factors and the C atoms with isotropic factors. The square- pyrimidal [MoO(SPh)4]- anion has the Mo atom lying 0.82 Ǻ from the basal plane of the four S atoms with Mo-O 1.699(9) Ǻ, the mean Mo-S bond lengths 2.403(5) Ǻ and the mean S...S distance 3.20(3) Ǻ. The geometry about the As atom in the Ph4As+ cation is regular tetrahedral, the mean As-C bond length being 1.91(1) Ǻ.

A mononuclear molybdenum(V) mono-oxo biphenyl-2,2′-dithiolate complex in which the metal resides within a cleft formed by the ligands and that exhibits N-H...S hydrogen bonding in the solid state

“…Essentially the same metal-oxygen distances (1.6±1.8 ) have been found for the Mo(IV) and Mo(VI) oxo-containing enzyme sites by X-ray crystallography [18,21,22,23,24,25] and X-ray absorption spectroscopy [72,73,74 190.59 (13) The Mo ion in 1 sits 0.703 out of the S 4 basal plane, which is on the low end of those reported for other Mo V (O)S 4 structures (0.687±0.82 ) [39,41,42,43,44,45,46,47], as well as when compared to the crystallographically characterized Mo(IV) and Mo(VI) enzyme sites with two dithiolene groups (0.4±1.7 ) [20,21,23,24,26]. The closer proximity of the molybdenum ion to the S 4 basal plane is also reflected in the O=Mo-S angles for 1, which are at least a degree smaller (mean 107.1, with two shorter angles near 104 and two longer angles near 110) than the other reported Mo V (O)S 4 structures, which have angles between 107.3 and 109.9 [39,41,42,43,44,45,46].…”

“…The Mo-oxo distance in 1 [1.684(8) ] is identical within error to other Mo V (O)S 4 complexes [39,40,41,42,43,44,45,46,47] and is typical for a terminal Mo=O [71]. Essentially the same metal-oxygen distances (1.6±1.8 ) have been found for the Mo(IV) and Mo(VI) oxo-containing enzyme sites by X-ray crystallography [18,21,22,23,24,25] and X-ray absorption spectroscopy [72,73,74 190.59 (13) The Mo ion in 1 sits 0.703 out of the S 4 basal plane, which is on the low end of those reported for other Mo V (O)S 4 structures (0.687±0.82 ) [39,41,42,43,44,45,46,47], as well as when compared to the crystallographically characterized Mo(IV) and Mo(VI) enzyme sites with two dithiolene groups (0.4±1.7 ) [20,21,23,24,26].…”

“…Nearly all of the handful of crystallographically characterized Mo V (O)S 4 complexes [39,40,41,42,43,44,45,46,47] have ligands that direct their steric bulk primarily away from the metal center. Here we report the synthesis and characterization of a unique Mo(V) complex, with dithiolate ligands that incorporate a biphenyl framework which also provides some steric protection that may inhibit the undesirable dimer formation.…”

Metalloprotein active site structure determination: Synergy between X-ray absorption spectroscopy and X-ray crystallography

“…Fig. 3 shows the temperature dependence of the Mo\S σ 2 value for two different but related molybdenum sulfur complexes having [Mo(V)_O] 3 − bound either with four thiophenolates [27] or with two benzenedithiols [28]. The Mo\S bond-lengths for the two complexes are very similar at 2.394 [27] and 2.377 Å [28].…”

“…3 shows the temperature dependence of the Mo\S σ 2 value for two different but related molybdenum sulfur complexes having [Mo(V)_O] 3 − bound either with four thiophenolates [27] or with two benzenedithiols [28]. The Mo\S bond-lengths for the two complexes are very similar at 2.394 [27] and 2.377 Å [28]. Additional vibrational modes contributing to the Mo\S σ 2 value for the thiophenolate species, and not present in the more restricted benzenedithiol species, cause the curve for the thiophenolate complex to be offset by + 0.0001 Å 2 (Fig.…”