Magnetic and spectroscopic properties of dimeric copper(II) N-benzoylvalinates.

The complexes cis-[RuVILO2]2+, cis-[RuVLO2]+ and cis-[RuIIL(MeCN)2]2+(L =N,N,N′,N′,3,6-hexamethyl-3,6-diazaoctane-1,8-diamine) have been prepared and their structures determined. The two Ru[double bond, length half m-dash]O bonds in cis-[RuVILO2]2+ are equivalent [1.795(9)Å] and the O–Ru–O angle is 112.0(4)°. In cis-[RuVLO2]+ the two Ru[double bond, length half m-dash]O distances are 1.751(3) and 1.756(4)Å, and the O–Ru–O angle is 115.1(2)°. The N(MeCN)–Ru–N(MeCN) angle in cis-[RuIIL(MeCN)2]2+ is 86.1(2)°. The cyclic voltammogram of cis-[RuVILO2]2+ in acetonitrile exhibits a reversible one-electron RuVI–RuV couple at 0.53 V vs. Ag–AgNO3(0.1 mol dm–3). In aqueous solutions, proton-coupled electron-transfer redox couples are observed. This complex is capable of oxidising a wide variety of organic substrates including 2,3-dimethylbutane and adamantane. Oxidation of saturated alkanes occurred preferentially at the tertiary C–H bond.