Reactivities and Structural and Electrochemical Studies of Coordinatively Unsaturated Arene(dithiolato)Ru(II) Complexes [(η6-p-cymene)Ru(1,2-S2C2B10H10-S,S‘)] and [(η6-C6Me6)Ru(1,2-S2C2B10H10-S,S‘)]

The addition reactions of 16-electron complexes [(η 6 -arene)Ru(Cab S,S ‘ )] [ 3: arene = p -cymene ( 3a ), C 6 Me 6 ( 3b ); Cab S,S ‘ = 1,2-S 2 C 2 B 10 H 10 - S,S ‘] with the nucleophiles PEt 3, CNBu t, and CO lead to the formation of the corresponding 18-electron complexes 4 − 6 [(η 6 -arene)Ru(Cab S,S ‘ )(L)] (L = PEt 3, CNBu t, CO), which have been characterized by X-ray crystallography. Investigation of the redox process in a series of these base-adduct metalladithiolene complexes by cyclic voltammetry reveals a large dependence of the redox potentials on the nature of the ancillary η 6 -arene and incoming L ligand. In an analogous manner, the reactivity of 3a toward arylamines ( 7 ) has been found to produce [(η 6 - p -cymene)Ru(Cab S,S ‘ )(L)] ( 8 ) [L = η 1 -NH 2 (CH 2 CH 2 )Ar, Ar = C 6 H 5 ( 8a ); C 6 H 4 OMe ( 8b ); C 6 H 3 (OMe) 2 ( 8c ); C 8 H 6 N ( 8d )], having molecular structures closely related to those of 4 and 5, as deduced by an electrochemical analysis and NMR studies. In addition, complex 3 reacts with a variety of substrates such as alkynes and a diazoalkane, generating a new class of dithiolato ruthenium(II) complexes incorporating alkene and alkylidene units. Thus, the syntheses of the half-sandwich ruthenium(II) complexes [(η 6 -arene)Ru{η 3 -( S,S,C ‘)-SC 2 B 10 H 10 SC‘R 2 }] [C‘R 2 = (COOMe)C C(COOMe) ( 9: arene = p -cymene ( 9a ), C 6 Me 6 ( 9b )), HC CPh ( 10: arene = C 6 Me 6 ( 10b )), CH 2 SiMe 3 ( 11: arene = p -cymene ( 11a ), C 6 Me 6 ( 11b ))] are reported, and the structure of 11b has been established by an X-ray diffraction study. The formation of 9 and 10 has also been electrochemically investigated.