A new series of iodocarbonyl ruthenium (II) complexes with unsymmetrical phosphine-phosphine sulfide ligands of the type Ph2P(CH2)(n)P(S)Ph-2, n=1-4: Isolation and structural investigation

Hexa-coordinated chelate complex cis-[Ru(CO)(2)I-2(P boolean AND S)] (1a) (P boolean AND S = eta(2)-(P, S)-coordinated) and penta-coordinated non-chelate complexes cis-(Ru(CO)(2)I-2(P similar to S)] (1b-d) {P similar to S = eta(1)-(P)-coordinated are produced by the reaction of polymeric [Ru(CO)(2)I-2](n), with equimolar quantity of the ligands Ph2P(CH2)(n)P(S)Ph-2 {n = 1(a), 2(b), 3(c), 4(d)} in dichloromethane at room temperature. The bidentate nature of the ligand a in the complex la leads to the formation of five-membered chelate ring which confers extra stability to the complex. On the other hand, 1:2 (Ru:L) molar ratio reaction affords the hexa-coordinated non-chelate complexes cis,cis,trans[Ru(CO)(2)I-2(P similar to S)(2)](2a-d) irrespective of the ligands. All the complexes show two equally intense terminal v(CO) bands in the range 2028-2103 cm(-1). The v(PS) band of complex la occurs 23 cm-1 lower region compared to the corresponding free ligand suggesting chelation via metal-sulfur bond formation. X-ray crystallography reveals that the Ru(II) atom occupies the center of a slightly distorted octahedral geometry. The complexes have also been characterized by elemental analysis, H-1, C-13 and P-31 NMR spectroscopy. (c) 2005 Elsevier B.V. All rights reserved.