Five-coordinate fluorobenzothiolate osmium(IV) complexes [Os(SR F) 4(PR 3)] (R F = C 6F 4H-4, R 3 = Ph 2(C 6F 5); R F = C 6F 4H-4, R 3 = (OPh) 3; R F = C 6F 5, R 3 = (OPh) 3): Single-crystal structures and solution structural characterization

Abstract

Reactions of OsO 4 with excess of HSR F and PR 3 in ethanol afford five-coordinate compounds [Os(SR F) 4(PR 3)] (R F = C 6F 4H-4, R 3 = Ph 2(C 6F 5) ( 1); R F = C 6F 4H-4, R 3 = (OPh) 3 ( 2); and R F = C 6F 5, R 3 = (OPh) 3 ( 3)). Single crystal X-ray diffraction studies of 1– 3 exhibit a common pattern with an osmium center in a trigonal-bipyramidal coordination arrangement. Axial positions are occupied by mutually trans thiolate and phosphine or phosphite ligands, while the remaining three equatorial positions are occupied by thiolate ligands. In compound 1 the tetrafluorophenyl rings of the equatorial ligands are directed away from the axial phosphine ligand in a “3-up” arrangement. In contrast, a “2-up, 1-down” arrangement was found in compounds 2 and 3, where only two of the fluorinated rings from the equatorial thiolates are directed towards the axial thiolate, while the fluorinated substituent of the third equatorial thiolate is directed towards the phosphine ligand. Structural characterization in solution by 1H, 31P{ 1H} and 19F NMR, variable temperature and COSY 19F– 19F NMR studies are discussed.