Triphos

Triphos is the name for certain organophosphorus ligands. They are air-sensitive white solids that function as tridentate ligands in coordination and organometallic chemistry. Triphos is the name for certain organophosphorus ligands. They are air-sensitive white solids that function as tridentate ligands in coordination and organometallic chemistry. Bis(diphenylphosphinoethyl)phenylphosphine is called triphos, is a linear tridentate triphosphine. It is prepared by the free-radical-catalysed addition of phenylphosphine to vinyldiphenylphosphine: This isomer of triphos is flexible and can bind to an octahedral metal center give either a facial or meridional isomers. Some derivatives are square planar complexes of the type + (M = Ni, Pd, Pt; X = halide). 1,1,1-Tris(diphenylphosphinomethyl)ethane is also called triphos. It is a tripodal ligand ('three-legged') of idealized C3v symmetry. It was originally prepared by the reaction of sodium diphenylphosphide and CH3C(CH2Cl)3: It forms complexes with many transition metals, usually as a tripodal ligand. Such complexes are used to analyze mechanistic aspects of homogeneous catalysts. For example, rhodium forms complexes with CH3C3 like , , and , provide model intermediates in the catalytic cycle for hydrogenation of alkenes. Triphos sometimes behaves as a bidentate ligand. Illustrative cases include fac- and , where M is Cr, Mo, or W. Triphos serves as a tridentate-bridging ligand in an icosahedral Au13 cluster. The phosphine bridges three chlorogold(I) groups to form the tripod molecule of trichloro-1,1,1-(diphenylphosphinomethyl)ethanetrigold(I), CH3C3. Like bis(diphenylphosphinoethyl)phenylphosphine, bis(diphenylphosphinophenyl)phenylphosphine is a linear tridentate ligand, but it is more rigid and more air stable. It is prepared from o-lithiated triphenylphosphine: