57322-00-6Relevant academic research and scientific papers
Exchange of isonitrile ligands in the complex [Mo(O)Cl(CNMe) 4]+ by the tetraphos ligand prP4: Stereochemical influences on the reaction course
S?ncksen, Ludger,R?mer, René,N?ther, Christian,Peters, Gerhard,Tuczek, Felix
, p. 472 - 479 (2011)
Reaction of [Mo(O)Cl(CNMe)4]+ with the linear tetraphos ligand meso and rac prP4 leads to a mixture of [Mo(O)Cl(κ4-meso-prP4)]+ and [Mo(O)Cl(CNMe)(κ3-rac-prP4)]+ which are identified by X-ray structural analysis and/or 31P NMR spectroscopy. In the meso κ4-product both of the phenyl groups of the central phosphorus atoms are oriented towards the oxo ligand whereas in the rac κ3-product one of these phenyl groups is oriented to the oxo and the other to the chloro ligand. The origin of the different coordination modes lies in the different steric demands of the oxo and chloro ligands. The influences of the steric interactions are enhanced by the fact that exchange of the fourth isonitrile is difficult. This hypothesis is supported by the preparation of the complex [Mo(O)Cl(CNMe)(dpepp)]PF6 whose isonitrile ligand is inert towards exchange by monophosphines, even under drastic conditions.
MONO- AND DI-NUCLEAR RHODIUM COMPLEXES OF meso- AND dl-1,1,4,7,10,10-HEXAPHENYL-1,4,7,10-TETRAPHOSPHADECANE. STEREOCHEMINAL CONTROL OF REACTIVITY AND COMPLEXATION GEOMETRY
Brown, John M.,Canning, Lewis R.
, p. 179 - 190 (2007/10/02)
Thermolysis of meso- and dl-1,1,4,7,10,10-hexaphenyl-1,4,7,10-tetraphosphadecane (200 deg C, 10 min) followed by fractional crystallisation from ethanol/dichloromethane gives two sharp-melting diastereomers.The higher melting compound, herein shown to be the meso-isomer, reacts with 1,5-cyclooctadiene-2,4-pentanedionatorhodium and HBF4 to give the dinuclear rhodium complex (3).This underwent hydrogenation slowly in methanol solution with deposition of rhodium metal and formation of a mononuclear complex (5) with four coordinated phosphorus nuclei, also obtained by independent synthesis.This proved to be highly susceptible to oxidation, forming a dioxygen complex (6) with P(1) and P(3) mutually trans.The lower melting dl-isomer likewise formed a dinuclear rhodium complex (4) on reaction with 1,5-cyclooctadiene-2,4-pentanedionatorhodium and HBF4.This reacted more rapidly than complex 3 with hydrogen forming a mononuclear dihydride (7) and metallic rhodium.In the presence of cyclohexene, a tetracoordinate phosphinerhodium complex (9) was formed.This reacted with oxygen to give dioxygen complex (10), although here P(1) and P(4) are mutually trans, and with carbon monoxide to give a five-coordinate monocarbonyl (11). The corresponding dirhodium bis-cyclooctadiene complex of 1,1,4,8,11,11-hexaphenyl-1,4,8,11-tetraphosphaundecane (13) (a single diastereomer of unknown stereochemistry), reacted with hydrogen in methanol to form a dinuclear solvate without reductive degradation.
