Novel catalysts for the carbonylation of methanol

Abstract

Rhodium(t) carbonyl complexes containing phosphino-thiolate and -thioether ligands are almost four times as active in catalysing the carbonylation of methanol to ethanoic acid as the previously known catalyst, [Rh12(C0)&; the crystal structure of one procatalyst, [Rh(SC6H4PPh2)(C0)l2, is reported.

Structural and Theoretical Studies ofortho-Substituted Triphenylphosphane Ligands and Their Rhodium(I) Complexes

“…The IR spectrum of 4 shows a CO stretching vibration at 2010 cm Ϫ1 , while the 31 P NMR spectrum gives a doublet at δ ϭ 67.2 with J RhϪP ϭ 152 Hz. Dilworth et al [14] have previously reported the synthesis of a brown precipitate, which they proposed on the basis of spectroscopic investigation to be compound 4. More recently, Steeg et al [15] published a crystallographic characterization of the same compound, which was, however, reached by a different route.…”

A highly efficient catalyst precursor for ethanoic acid production: [RhCl(CO)(PEt3)2]; X-ray crystal and molecular structure of carbonyldiiodo(methyl)bis(triethylphosphine)rhodium(III)

“…There have been attempts to modify [Rh(CO) 2 I 2 ] 2 by using electron donating ligands. [3][4][5][6] For instance, Baker et al 3 used [RhI(CO)(Ph 2 PCH 2 P(S)Ph 2 )] to enhance the rate of carbonylation at 185 °C. Cavell and coworkers 4 prepared complexes of the form, [RhCl(CO)(PPh 2 CH 2 PPh 2 NR)], where R is a substituted phenyl group.…”

Novel Group 9 Metal Complexes Containing an S,S'-Chelating o-Carboranyl Ligand System: Synthesis, Crystal Structures, and Electrochemical Properties of Dinuclear [{(cod)M}2(S,S'-S2C2B10H10)] (cod = 1,5-cyclooctadiene;M = Rh OR Ir)] and Mononclear Cp*CoI[S,S'-S(S=PMe2)C2B10H10] Metal Complexs

“…In a recent study of [{(Cp)Co} 2 (S,S'-S 2 C 2 B 10 H 10 )], 15a we observed a reversible oxidation wave at an E 1/2 of 0.19 V, which we assigned to the redox wave of the bimetallic Co-Co bond by removal/ addition of an electron. An analogous electron transfer series including a bimetallic species with Ru 3+ -Ru 3+ metal centers has been observed for the oxidation of Cp*Ru(µ-SPh) 3 15a,c Thus, the reversible oxidation wave of 3a and 3b can be assigned to the oxidation-reduction of the dinuclear Rh-Rh and Ir-Ir bonds, respectively. The reversibility of the M-M redox wave seems to stem from the low angular distortion of both the M-S-C-C'-S' five-membered ring and flexible M-S-S' bicyclic triangles, which maintains the intimacy of the two nuclei, enabling the M-M bond to reform after oxidation.…”

“…Among the dinuclear metal complexes synthesized to date, those in which the two metal atoms are held in close proximity by sulfur-containing bridging ligands (e.g., thiolate, 1 aminothiolate, 2 and phosphinothiolate 3 ) have received particular attention. 4 Recent reports of unusually stable P,S-, 5 C,N-, 6 C,P-, 7 N,P-, 8 N,S-, 9 and S,S'-chelating 10 o-carboranyl metal complexes suggest that the chelation characteristics, rigid conformation, and o-carboranyl backbone of dithiolates may make these ligands particularly well suited to the stabilization of dinuclear metal intermediates in organometallic reactions.…”