Ruthenium complexes containing hexamethylbenzene and butadienesulfonyl ligands: Synthesis and reactivity toward CO, nitrogen and phosphine ligands

Abstract

The heterometallic tetranuclear complexes [(HMB)Ru(Cl)2(5-η-CH2CHCRCHSO2)(Li)(THF)]2 [R = H, 3; Me, 4] were synthesised by reaction of [(HMB)Ru(μ-Cl)Cl]2 (1) (HMB = η6-C6Me6) and an excess of [CH2CHCRCHSO2Li] (R = H, Me), whereas mononuclear complexes [(HMB)Ru(Cl)(1,2,5-η-CH2CHCRCHSO2)] (R = H, 7; Me, 8) were obtained when [CH2CHCRCHSO2K] was used. Complex [(HMB)Ru(Cl)2(5-η-CH2CHCHCHSO2)(K)(THF)]2 (5) was spectroscopically detected by 1H and 13C NMR. Solution experiments demonstrated that the above mentioned compounds transform into new ones by simply dissolving or standing in solution. Isolation of the ion pair complex [(HMB)Ru(Cl)(5-η-CH2CHCHCHSO2)(5-η-CH2CHCHCHSO2K)] (9) and subsequent addition of AgBF4 results in the formation of [(HMB)Ru(1,2,5-η-CH2CHCHCHSO2)(5-η-CH2CHCHCHSO2)] (10). Further reactivity of complexes 7 and 8 showed the addition reactions of a variety of ligands such as CO, deuterated and non-deuterated pyridine and acetonitrile, resulting in complexes of the type [(HMB)Ru(Cl)(5-η-CH2CHCRCHSO2)L] [R = H, L = CO, 11; Py, 12, Py-d5, 12D; R = Me, L = Py, 13, Py-d5, 13D; R = H, L = CD3CN, 14D]. Treatment with phosphines afforded the addition products [(HMB)Ru(Cl)(5-η-CH2CHCHCHSO2)L] (L = PMe3, 15; PPh3, 16; PHPh2, 17) and the formation of the dichloride complexes [(HMB)Ru(Cl)2PR3] 15Cl, 16Cl and 17Cl, respectively, as by-products. Compounds 8 and 15 were characterized by single crystal X-ray crystallography. Additionally, a comparative study with isoelectronic and related compounds was undertaken.