SYNTHESIS, ELECTROCHEMISTRY AND X-RAY CRYSTAL-STRUCTURE OF CIS-[RUIIIL1(CL)(H2O)][CLO4]2.2H2O[L1 = N,N'-DIMETHYL-N,N'-BIS(2-PYRIDYLMETHYL)ETHYLENEDIAMINE] - ELECTROCHEMICAL OXIDATION OF ALCOHOLS AND TETRAHYDROFURAN BY CIS-[RUVL1(CL)O]2

Reaction of K2[RuCl5(H2O)] with N,N'-dimethyl-N,N'-bis(2-pyridylmethyl)ethylenediamine (L1) in ethanol gave cis-[Ru(III)L1Cl2]+ and then cis-[Ru(III)L1(Cl) (H2O)]2+ upon reaction with Ag(I) in water. The structure of cis-[Ru(III)L1(Cl) (H2O)][ClO4]2.2H2O has been established by X-ray crystallography: space group Pbca, a = 10.863(1), b = 21.548(2), c = 21.912(2) angstrom. The measured Ru-Cl and Ru-OH2 distances are 2.307(4) angstrom and 2.070(9) angstrom respectively. A cyclic voltammogram of cis- [Ru(III)L1 (Cl)-(H2O)]2+ in 0.1 mol dm-3 CF3CO2H shows three reversible/quasi-reversible couples at 1.29, 0.93 and 0.23 V vs. saturated calomel electrode assigned to the couples Ru(V)-Ru(IV), Ru(IV)-Ru(III) and Ru(III)-Ru(II). The complex cis-[Ru(III)L1 (Cl) (H2O)]2+ is an active catalyst for the electrochemical oxidation of alcohols and tetrahydrofuran. The second-order rate constant for the oxidation of benzyl alcohol by electrochemically generated cis-[Ru(V)L1(Cl)O]2+ is estimated to be 8.4 x 10(4) dm3 mol-1 s-1.