Oxidation behaviour of the unsaturated diruthenium species [Ru2(µsb-CO)2(CO)2{µ-(PriO)2PNEtP(OPri)2}2]
Abstract
Treatment of the formally unsaturated species [Ru2(µsb-CO)2(CO)2(µ-etipdp)2][sb = semi-bridging, etipdp =(PriO)2PNEtP(OPri)2] with silver(I) salts such as AgSbF6 or AgBF4 in MeCN or PhCN led directly to the formation of the disolvated species [Ru2(CO)4(RCN)2(µ-etipdp)2]X2(R = Me or Ph; X = SbF6 or BF4), with no intermediates being detected. In contrast, as established spectroscopically, oxidation of this complex with silver(I) salts in very weakly co-ordinating solvents such as acetone or methanol afforded silver adducts of the parent species. Also, reaction with the electron acceptor tcnq (7,7,8,8-tetracyano-p-quinodimethane) in tetrahydrofuran (thf) gave the electron-transfer salt [Ru2(η1-tcnq)(CO)4(thf)(µ-etipdp)2][tcnq], while with p-chloranil(tetrachloro-1,4-benzoquinone) produced [Ru2(µ-Cl)(CO)4(µ-etipdp)2][p-OC6Cl4O]2 as a consequence of the benzoquinone functioning as a chlorinating agent as well as an electron acceptor. Cyclic voltammograms of [Ru2(µsb-CO)2(CO)2(µ-etipdp)2] and [Ru2(CO)4(RCN)2(µ-etipdp)2][SbF6]2(R = Me or Ph) have been measured in both aceto- and benzo-nitrile and are readily interpreted in terms of the redox process [Ru2(µsb-CO)2(CO)2(µ-etipdp)2]+ 2RCN [graphic omitted] [Ru2(CO)4(RCN)2(µ-etipdp)2]2+. The structure of the acetonitrile species [Ru2(CO)4(MeCN)2(µ-etipdp)2][BF4]2·CH2Cl2 has been determined X-ray crystallographically.