A novel synthesis of diphenyl(2-thienyl)phosphine, along with its' oxide, sulfide and selenide derivatives, is reported here. These phosphines have been characterized by NMR, IR, MS and X-Ray crystallography. The phosphine oxide derivative was reacted with a selection of lanthanide(m) nitrates and triflates, LnX(3), to give the resultant metal-ligand complexes. These complexes have also been characterized by NMR, IR, MS and X-Ray crystallography. Single crystal X-Ray diffraction data shows a difference in metal-ligand complex stoichiometry and stereochemistry depending on the counteranion (nitrate vs. triftate). The [Ln (Ar3P=O)(3)(NO3)(3)] ligand-nitrate complexes are nine-coordinate to the metal in the solid state (bidentate nitrate), featuring a 1: 3 lanthanide ligand ratio and bear an overall octahedral arrangement of the six, coordinated ligands. Our (Ln(Ar3P=O)(3)(NO3)(3)] ligand-nitrate complexes gave three examples of fac-stereochemistry, where mer-stereochemistry is almost universally observed in the literature of highly related [Ln (Ar3P=O)(3)(NO3)(3)] complexes. For the Tb complexes, two different arrangements of the ligands around the metal were observed in the solid state for (Tb(Ar3P=O)(3)(NO3)(3)] and [Tb(Ar3P=O)(4)(OTf)(2)] (OTf]. [Tb(Ar3PO)(3)(NO3)(3)] is strictly nine-coordinate, ligand mer-stereochemistry in the solid state, and (Tb(Ar3P=O)(4)(OTf)(2)] [OTf] is strictly octahedral, six-coordinate, with a square-planar stereochemical arrangement of the phosphine oxide ligands around the metal.
