Highly-charged organic nanoparticles: redox-active dendrimers incorporating 9,10-bis (1,3-dithiol-2-ylidene)-9,10-dihydroanthracene units

摘要

The incorporation of 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene units into dendritic structures has been achieved by convergent routes. The key starting material is the 4-(hydroxymethyl) derivative 3. The branches contain aryl ester and aryl ether groups and the core reagent is benzene-1,3,5-tricarbonyl chloride. Dendrimers 10, 15 and 18 with 6 and 12 redox units at the periphery have been characterised by ~1H NMR spectroscopy, elemental analysis, mass spectrometry, UV-vis spectroscopy and solution electrochemistry. The 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene redox chemistry is r4etained in the dendrimer structures: clean formation of hexa (dication) and dodeca (dication) species is observed upon electrochemical oxidation. These highly-charged species enjoy remarkable electrochemical stability as their reduction to the neutral species is thwarted by the loss of aromaticity and the marked conformational change which accompanies this process. Molecular modelling studies were performed on 10, 10~(12+), 18 and 18~(24+) by molecular mechanics.