Ruthenium(II) carbonyl complexes containing tertiary phosphine chalcogenide ligands of the type Ph 3PX; X=O, S, Se

Abstract

The reactions of polymeric complex [Ru(CO) 2Cl 2] n with triphenyl phosphine chalcogenide ligands Ph 3PX; X=O( a), S( b), Se( c) in 1:1 (Ru:L ratio) molar ratio gives five-coordinate complexes of the type [Ru(CO) 2Cl 2(Ph 3PX)]( 1a– c) while 1:2 (Ru:2L ratio) molar ratio produces six-coordinate [Ru(CO) 2Cl 2(Ph 3PX) 2]( 2a– c) complexes. The complexes 1a– c and 2a– c exhibit two equally intense ν(CO) bands in the range 2059–1989 and 2050–1980 cm −1, respectively, indicating cis-disposition of the two terminal carbonyl groups. The values of ν(CO) frequencies irrespective of the complexes, in general, follow the order: Ph 3PO > Ph 3PS > Ph 3PSe which may be ascribed in terms of “Soft–Hard” (Ru(II)–O) and “Soft–Soft” (Ru(II)–S/Se) interactions. The ν(PX) bands of the complexes observed in the range 1173–538 cm −1 are 19–41 cm −1 lower than those of the corresponding free ligands indicating the formation of Ru–X bonds. The molecular structure of the complex [Ru(CO) 2Cl 2(Ph 3PS) 2] was determined by single X-ray crystallography. The crystal is monoclinic, space group Cc; a=11.4990 Å, b=17.3966 Å, c=18.4788 Å; α=90°, β=98.160°, γ=90°. In the molecule, the Ru(II) atom occupies the center of a slightly distorted octahedral geometry which consists of two trans-S atoms of two Ph 3PS ligands, two cis-CO groups and two cis-chlorides. The complexes have also been characterized by elemental analysis, 1H, 13C and 31P NMR spectroscopy.