Synthesis, characterisation and thermal studies of ruthenium(II) carbonyl complexes of functionalised tripodal phosphine chalcogen donor ligands, [CH3C(CH2P(X)Ph2)3], where X=Se, S, O

The polymeric ruthenium(II) carbonyl complex, [Ru(CO)(2)Cl-2](n) reacts with 1,1,1-tris-(diphenylphosphinomethyl)ethane trichalcogenide ligands, [CH3C(CH2P(X)Ph-2)(3)], where X=Se(a), S(b) and O(c) in 1:1 (metal:ligand) molar ratio to afford hexa-coordinated complexes of the type eta(2)-(X,X)[Ru(CO)(2)Cl2P3X3] (1a-c). The complexes la-c exhibit two equally intense v(CO) bands in the range 1979-2060 cm(-1) indicating cis-disposition of the two terminal carbonyl groups. The values of nu(CO) frequencies containing different ligands, in general, follow the order: P3O3 > P3S3 > P3Se3 which may be explained in terms of Soft-Hard' (Ru(II)-O) and 'Soft-Soft' (Ru(II)-S/Se) interactions. The complexes have been characterized by elemental analyses, mass, H-1, P-31, Se-77 and C-13 NMR spectroscopy. The thermal stability of the complexes has also been studied. (c) 2008 Elsevier B.V. All rights reserved.