Michael James Baker

Chiral aryl diphosphites: a new class of ligands for hydrocyanation catalysis

The new diphosphite 1 derived from R-2,2′-binaphthol and its nickel(0) complex are described; optical yields for the hydrocyanation of norbornene are 38%.

Chelating diphosphite complexes of nickel(0) and platinum(0): their remarkable stability and hydrocyanation activity

The synthesis, stability and hydrocyanation catalytic activity of nickel(0) complexes of the diphosphite 1 derived from 2,2′-biphenol are described; the X-ray crystal structures of the ligand 1 and its platinum(0) complex 2b are reported.

A tetraphos ligand with C3 symmetry

An optically active tetraphos ligand of C3 symmetry and its platinum(0) coordination chemistry are described.

Cis-[RhI(CO)(Ph2PCH2P(S)Ph2)]: a new catalyst for methanol carbonylation

The complex cis-[[graphic omitted]Ph2)] is eight times more active than the classic Monsanto catalyst [RhI2(CO)2]– for the carbonylation of methanol at 185 °C offering the first promoted system effective under conditions which allow industrially realistic rates; the X-ray crystal structure of the analogue cis-[[graphic omitted]Ph2)] is reported together with in situ spectroscopic evidence for species in the catalytic cycle.

NOVEL CATALYSTS FOR THE CARBONYLATION OF METHANOL

Rhodium(I) 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, [Rhl2(CO)2]–; the crystal structure of one procatalyst, [Rh(SC6H4PPh2)(CO)]2, is reported.

2-Methoxyphenyl phosphite complexes of platinum(0) and nickel(0)

The compounds P(OC6H4OMe-2)3 and P(OC6H4OMe-2)(OC6H4Me-4)2 have been prepared. The platinum(0) complex [Pt{P(OC6H4OMe-2)3}3]1 can be made by the reduction of [PtCl2{P(OC6H4OMe-2)3}2] in the presence of the phosphite or by addition of the latter to tris(η2-norbornene)platinum, and [Pt(η2-C2H4){P(OC6H4OMe-2)3}2]2 by the reduction of [PtCl2{P(OC6H4OMe-2)3}2] in the presence of ethene or by adding of the phosphite to [Pt(η2-C2H4)3]. The crystal structures of the ligand P(OC6H4OMe-2)3 and complex 2 have been determined and the effect of co-ordination on the conformation of the phosphite substituents is discussed. The ethene ligand in 2 is readily substituted by other alkenes and alkynes to give complexes 3–9 of the general type [Pt(η2-alkene){P(OC6H4OMe-2)3}2] or [Pt(η2-alkyne){P(OC6H4OMe-2)3}2]. Reduction of [Ni(acac)2](acac = acetylacetonate) with AlMe3 in the presence of ethene gives [Ni(η2-C2H4){P(OC6H4OMe-2)3}2]10. The air-sensitive complex [Ni{P(OC6H4OMe-2)3}3]11 can be generated in solution by treatment of [Ni(cod)2](cod = cycloocta-1,5-diene) or 10 with the phosphite ligand. The tetrahedral complex [Ni{P(OC6H4OMe-2)(OC6H4Me-4)2}4]12 is readily made from [Ni(cod)2] and the phosphite. The catalytic activity of 11 and 12 for the monohydrocyanation of buta-1,3-diene is discussed in relation to similar well known catalysts and it is concluded that the methoxy groups inhibit the catalysis probably by a combination of steric hindrance and weak co-ordination of the ether oxygen.