Monohydride complexes of W (IV) containing bulky selenolate ligands: X-ray crystal structure determination of [WH(SeC 6H 3Pr i2-2,6) 3(PMe 2Ph) 2

Abstract

The complexes [WH(SeR) 3(L) (PMe 2Ph)] (R=C 6H 3Pr i 2-2,6 or C 6H 2Me 3-2,4,6; L=PMe 2Ph, pyridine and N-methylimidazole) have been prepared by reaction of [WH 6(PMe 2Ph) 3] or cis-[W(N 2) 2(PMe 2Ph) 4] with the selenol HSeR and characterized by FAB mass spectroscopy, 31P, 1H and 77Se NMR, IR and UV-Vis spectroscopies. A single crystal X-ray diffraction study of complex [WH(SeC 6H 3Pr i 2-2,6) 3(PMe 2Ph) 2] at 178 K reveals a distorted trigonal bipyramidal geometry of the WSe3P2 core with the hydride located along an SeP edge of the trigonal bipyramid; the hydride position was refined with a W-H distance of 1.51(6) A and an H-W-P angle of 53°. This small angle results in a large 2 J(H,P) coupling of 99 Hz. The bulky Se ligands adopt a 'two-up, one-down' arrangement of aryl substituents. The 2 J(SeP) values show a high degree of dependence on the P-M-Se angles or the P-M-Se-C dihedral angle. This may be useful for assigning geometries of selenolate complexes. Improved syntheses of the starting compounds [WH 6(PMe 2Ph) 3] and cis-[W(N 2) 2(PMe 2Ph) 4] are reported.