New Linear π-Conjugated Diruthenium Compounds Containing Axial Tetrathiafulvalene-acetylide Ligands

Abstract

Under the weak base conditions, diruthenium(III) tetrakis- N, N′ -dimethylbenzamidinate (DMBA) nitrate (Ru 2 (DMBA) 4 (NO 3 ) 2 ) reacted with electroactive tetrathiafulvalene acetylene ligands, HC≡C–TTF1 (5-ethynyl-2-(4,5-dimethyl-1,3-dithiol-2-ylidene)benzo[ d ][1,3]dithiole) and HC≡C–TTF2 (2-(5-ethynylbenzo[ d ][1,3]dithiol-2-ylidene)benzo[ d ][1,3]dithiole), to afford new compounds trans -Ru 2 (DMBA) 4 (C≡C–TTF1) 2 ( 1 ) and trans -Ru 2 (DMBA) 4 (C≡C–TTF2) 2 ( 2 ), respectively. The trans orientation and the planar nature of the ethynyltetrathiafulvalene ligands around the Ru 2 (III,III) core were supported by the single-crystal X-ray diffraction study of compound 1 . Both compounds 1 and 2 and their TTF ligand precursors were characterized with the spectroscopic and voltammetric techniques, which revealed a minimal electronic interaction between the two TTF moieties within the same compound. The electronic structure of trans -Ru 2 (DMBA) 4 (C≡C–TTF) 2 was analyzed based on a DFT calculation of a model compound, and the resultant distribution of valence MOs is consistent with the voltammetric results.