Abstract
The cyclocondensation reaction between rigid, electron-rich aromatic diamines and 1,1'-bis(2,4-dinitrophenyl)-4,4'-bipyridinium (Zincke) salts has been harnessed to produce a series of conjugated oligomers containing up to twelve aromatic/heterocyclic residues. These oligomers exhibit discrete, multiple redox processes accompanied by dramatic changes in electronic absorption spectra.
Highlights
The colour of cationic bipyridinium residues is highly dependent on the electronic ground state energy of the molecule, which can be finely tuned by varying the substituents.[20,21,22,23,24]
In this study we report an efficient synthesis of 4,4′-bipyridinium-based aromatic oligomers (1–3) and their spectro-electrochemical properties
Combined results from cyclic voltammetry (CV) and UV-vis SEC demonstrate that, in these three oligomers, their ground states are not planar, which results in a twisted configuration between the phenyls and viologens
Summary
Bipyridinium residues are amongst the most intensively studied building blocks in supramolecular chemistry.[1,2,3] They have found widespread application in molecular systems that exhibit controlled switching,[4,5,6,7,8] rotational motion[9,10,11] and potential for data storage.[12,13,14,15] Many of these complex nanosystems harness the controllable electrochemical properties of 4,4′-bipyridinium ions (“viologens”) in either their synthesis or application.[16]. We studied the chemically reversible redox process using TEA and trifluoroacetic acid (TFA), as described previously for the macrocyclic systems.[60] Fig. 2(A) shows the 1H NMR spectrum of an orange solution of trimer 3, which exhibits clearly resolved signals in the aromatic region (7.5 to 10.0 ppm), as well as two distinct resonances from the methoxy-ether and methoxy-ester residues (3.8 and 4.0 ppm).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
