97879-19-1Relevant academic research and scientific papers
Synthesis, Structure, and Reactivity of Zerovalent Group 6 Metal Pentacarbonyl Aryl Oxide Complexes. Reactions with Carbon Dioxide
Darensbourg, Donald J.,Sanchez, Kathryn M.,Reibenspies, Joseph H.,Rheingold, Arnold L.
, p. 7094 - 7103 (2007/10/02)
The synthesis of (M=Cr, Mo, W; R=Ph, C6H4CH3-m) from the reaction of M(CO)5THF and in tetrahydrofuran is reported.In the absence of a carbon monoxide atmosphere these mononuclear species readily aggregate via a CO dissociation pathway to the tetranuclear species 44.It was possible to isolate pure crystalline samples of the derivatives by precipitation from solutions under a carbon monoxide atmophere.The complex was characterized in the solid-state by X-ray crystallography. crystallizes in the space group with cell dimensions a=9.416(3) Angstroem, b=12.665(2) Angstroem, c=18.371(3) Angstroem, α=92.38(1) deg, β=94.50(2) deg, γ=95.85(2) deg, V=2168.3 Angstroem3, Z=4, and RF=7.71percent.An additional salt of the tungsten phenoxide complex has been crystallized that contains 0.5 equiv of water, i.e., .This species has as well been characterized by X-ray crystallography. crystallizes in the space group P21/c with cell dimensions a=17.545(5), b=25.322(8), c=10.337(3), β=102.52(3) deg, V=4483(2) Angstroem3, Z=8, and RF=5.60percent.The water molecule is shown to be hydrogen bonded between ligated -OPh ligands of adjacent W(CO)5OPh(1-) anions.This intermolecular hydrogen-bonding interaction is observed in tetrahydrofuran solution as well between alcohols and W(CO)5OPh(1-).The M(CO)5OR(1-) (M=Cr, W) derivatives were demonstrated to undergo facile insertion reactions with CO2, COS, and CS2 to afford the corresponding metal pentacarbonyl phenyl carbonate, phenyl thiocarbonate, and phenyl dithiocarbonate complexes.This carbon dioxide insertion reaction isreversible, and the rate of insertion is unaffected by carbon monoxide pressures up to 10 atm.The relative rates of insertion of CO2, COS, and CS2 into the M(CO)5OPh(1-) anions are Cr > W and CS2 > COS > CO2.On the other hand, in the presence of ligands at the metal center that are sterically more demanding than CO, i.e., cis-M(CO)4(L)OPh(1-) derivatives, the relative rates of carbon dioxide insertion are W > Cr and L=P(OMe)3 > PMe3 > PPh3.The W(CO)5XC(X)OPh(1-) (X=O or S) derivatives underwent hydrolysis in the presence of small quantities of water to provide the corresponding W(CO)4(CX2O)(2-) products.One of these products, namely, 2, was subjected to an X-ray crystallographic investigation.The salt crystallizes in the space group with cell dimensions a=10.513(5) Angstroem, b=15.881(10) Angstroem, c=8.130(6) Angstroem, α=101.69(6) deg, β=92.12(5) deg, γ=83.25(5) deg, V=1319.8 Angstroem3, Z=2, and RF=3.01percent.The W-O bond distances (2.204 Angstroem) are quite similar to those observed (2.203 Angstroem) in the W-OPh(1-) complexes.The carbonate ligand is bidentate with a very acute O-W-O angles of 59.4 deg.
Synthesis and characterization of polynuclear chromium carbonyl tetraanions
McNeese, Timothy J.,Mueller, Timothy E.,Wierda, Derk A.,Darensbourg, Donald J.,Delord, Terry J.
, p. 3465 - 3468 (2008/10/08)
Polynuclear chromium carbonyl complexes of the general formula [Cr4(CO)12(μ3-OR)4]4- (R = H, C6H5) have been prepared as their Et4N+ salts. Reaction of Cr(CO)6 with excess hydroxide ion in aqueous THF solution yields [Cr4(CO)12(μ3-OH)4]4-. The X-ray structure of [Et4N]4[Cr4(CO)12(μ 3-OH)4] has been determined. The structural features of the tetraanion consist of a cubane-like A4B4 (A = chromium, B = oxygen) arrangement with triply bridging μ3-hydroxide groups and Cr(CO)3 units. The Cr-Cr distance within the Cr4O4 core is nonbonding (3.33 (5) A? (average)), consistent with a closed-shell metal configuration. The crystals are monoclinic (space group I2/a) with cell constants a = 21.827 (7) A?, b = 12.236 (2) A?, c = 22.899 (4) A?, β = 116.49 (2)°, V = 5474 (5) A?3, and Z = 8. The μ3-phenoxide derivative, [Et4N]4[Cr4(CO)12(μ 3-OC6H5)4], has been prepared by treatment of Cr(CO)3(CH3CN)3 with [Et4N][OC6H5] in equimolar concentrations and characterized by spectroscopic methods.
