Diruthenium acetylide compounds with masked diazonium capping groups

Reported in this contribution are the synthesis and characterization of the following diruthenium arylacetylide compounds containing dialkyl-triazene capping groups: Ru-2(ap)(4)-(C C-4-C6H4-N3Et2) (2), Ru-2(ap)(4)-(C C-(3)-C6H4-N3Et2) (3), and trans-[Ru-2(DMBA)(4)](-C C-4-C6H4-N3Et2)(2) (4), where ap is 2-anilinopyridinate and DMBA is N,N-dimethylbenzamidinate. Compounds 2/3 were prepared by the addition of diethylamine to the diazonium intermediate, Ru-2(ap)(4)-(C C-3/4-C6H4-N-2(+)), under basic conditions, and compound 4 was synthesized from Ru-2(DMBA)(4)(NO3)(2) and HC C-4-C6H4-N3Et2 under weakly basic conditions. An X-ray study of 4 provided a unique structural example of inorganic compounds bearing dialkyletriazene functional groups, and revealed a minimal alteration in the first coordination sphere of Ru-2 core upon the attachment of dialkyletriazene caps. Similar to previously reported diruthenium compounds, 2, 3 and 4 display rich redox chemistry with a reversible diruthenium oxidation and reduction, as well as an oxidation of the triazene group to a radical. (C) 2013 Elsevier B. V. All rights reserved.