Diruthenium acetylide compounds with masked diazonium capping groups

• Novel diruthenium arylacetylide compounds with diethyl-triazene capping groups were prepared.
• Rich redox characteristics of new compounds were revealed by voltammetric studies.
• Compounds can be readily converted to the corresponding diazoniums with Brønsted acid.

Reported in this contribution are the synthesis and characterization of the following diruthenium arylacetylide compounds containing dialkyl–triazene capping groups: Ru2(ap)4-(CC-4-C6H4–N3Et2) (2), Ru2(ap)4-(CC-3-C6H4–N3Et2) (3), and trans-[Ru2(DMBA)4](-CC-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, Ru2(ap)4-(CC-3/4-C6H4–N2+), under basic conditions, and compound 4 was synthesized from Ru2(DMBA)4(NO3)2 and HCC-4-C6H4–N3Et2 under weakly basic conditions. An X-ray study of 4 provided a unique structural example of inorganic compounds bearing dialkyl–triazene functional groups, and revealed a minimal alteration in the first coordination sphere of Ru2 core upon the attachment of dialkyl–triazene 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.

Reported herein are the synthesis and characterization of diruthenium arylacetylide compounds bearing diethyl–triazene as the masked surrogates of corresponding diazonium salts.Figure optionsDownload as PowerPoint slide