625385-16-2Relevant academic research and scientific papers
An alternative strategy to an electron rich phosphine based carbonylation catalyst
Dutta, Dipak K.,Woollins, J. Derek,Slawin, Alexandra M.Z.,Konwar, Dilip,Das, Pankaj,Sharma, Manab,Bhattacharyya, Pravat,Aucott, Stephen M.
, p. 2674 - 2679 (2007/10/03)
The complexes [Rh(CO)Cl(2-Ph2PC6H4COOMe)], 1, and trans-[Rh(CO)Cl(2-Ph2PC6H4COOMe) 2], 2, have been synthesized by the reaction of the dimer [Rh(CO)2Cl]2 with 2 and 4 molar equivalents of 2-(diphenylphosphino)-methyl benzoate. The complexes 1 and 2 show terminal v(CO) bands at 1979 and 1949 cm-1 respectively indicating high electron density at the metal centre. The molecular structure of the complex 2 has been determined by single crystal X-ray diffraction. The rhodium atom is in a square planar coordination environment with the two phosphorus atoms trans to each other; the ester carbonyl oxygen atom of the two phosphine ligands points towards the rhodium centre above and below the vacant axial sites of the planar complex. The rhodium-oxygen distances (Rh ... O(49) 3.18 A Rh ...) and the angle O(19) ... Rh ... O(49) 179° indicate long range intramolecular secondary Rh ... O interactions leading to a pseudo-hexacoordinated complex. The complexes 1 and 2 undergo oxidative addition (OA) reactions with CH3I to produce acyl complexes [Rh(COCH3)ClI (2-Ph2PC6H4COOMe)], 4, and trans-[Rh(COCH3)ClI(2-Ph2PC6H4COO-Me )(2-Ph2PC6H4COOMe)], 5, and the kinetics of the reactions reveal that the complex 1 undergoes faster OA reaction than that of the complex 2. The catalytic activity of the complexes 1 and 2 in the carbonylation of methanol were higher than that of the well known species [Rh(CO)2I2]- and the complex 1 shows higher activity than 2.
