Ruthenium(II) carbonyl complexes containing tertiary phosphine chalcogenide ligands of the type Ph3PX; X=O, S, Se

Abstract

The complexes [Ru(CO) 2 Cl 2 (Ph 3 PX)] and [Ru(CO) 2 Cl 2 (Ph 3 PX) 2 ] are produced on treatment of [Ru(CO) 2 Cl 2 ] n with 1:1 and 1:2 mol ratio of the ligands Ph 3 PX; X=O, S, Se, respectively. The molecular structure of [Ru(CO) 2 Cl 2 (Ph 3 PS) 2 ] was determined by single X-ray crystallography and Ru atom occupies the center of the slightly distorted octahedral geometry. The reactions of polymeric complex [Ru(CO) 2 Cl 2 ] n with triphenyl phosphine chalcogenide ligands Ph 3 PX; X=O( a ), S( b ), Se( c ) in 1:1 (Ru:L ratio) molar ratio gives five-coordinate complexes of the type [Ru(CO) 2 Cl 2 (Ph 3 PX)]( 1a – c ) while 1:2 (Ru:2L ratio) molar ratio produces six-coordinate [Ru(CO) 2 Cl 2 (Ph 3 PX) 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 3 PO > Ph 3 PS > Ph 3 PSe 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) 2 Cl 2 (Ph 3 PS) 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 3 PS ligands, two cis -CO groups and two cis -chlorides. The complexes have also been characterized by elemental analysis, 1 H, 13 C and 31 P NMR spectroscopy.