Enantiorecognition towards L- and D-DOPA on easy-to-prepare inherently chiral film electrodes

We have recently shown1,2 that oligomers endowed with \u201cinherent chirality\u201d display high chirality manifestations plus a pool of unprecedented properties. In particular, in the very last months we have demonstrated that electrooligomerization (especially in ionic liquids) of our inherently chiral monomers on screen\u2010printed electrodes and on glassy carbon tip electrodes affords inherently chiral electroactive films of outstanding enantiodiscrimination ability towards a series of chiral probes of quite different bulkiness and chemical nature (also of pharmaceutical interest like DOPA, common antibiotics and FANS)3. The general validity of the "inherent chirality" concept has been confirmed by characterizing monomers and related films based on different atropisomeric biheteroaromatic scaffolds (i.e. bis\u2010benzothiophene, bis\u2010indole, and \u201call thiophene\u201d core). In this work the enantiorecognition ability of our smart films towards L\u2010 and D\u2010DOPA will be presented focusing on the variation in voltammetric peak separation of the probe enantiomers when changing i) the medium (e.g. increasing pH), ii) the nature of electrode material and iii) the probe carboxylic unit (i.e. DOPA methyl ester). The impressive enantiomer peak potential separation combined with the peak current linear dynamic ranges enables to estimate enantiomeric excesses in probe enantiomeric mixtures. Such synthetic electrode surfaces able to neatly discriminate the antipodes of chiral probes as separate peaks are unprecedented in literature, opening the way to the development of efficient chiral voltammetric sensors. Figure. Effect of the variation in the pH medium on the enantiorecognition ability of our bithianaphthene\u2010based (BT2\u2010T4)n inherently chiral electrodes with L\u2010 and D\u2010DOPA probes, superimposed on a speciation plot of DOPA. This work was supported by Fondazione Cariplo (Grant no. 2011\u20100417) References [1] F. Sannicol\uf2, S. Arnaboldi, T. Benincori, V. Bonometti, R. Cirilli, L. Dunsch, W. Kutner, G. Longhi, P. R. Mussini, M. Panigati, M. Pierini and S. Rizzo, Angewandte Chemie Int. Ed., 53 (2014), 2623 [2] F. Sannicol\uf2, P. R. Mussini, T. Benincori, R. Cirilli, S. Abbate, S. Arnaboldi, S. Casolo, E. Castiglioni, G. Longhi, R. Martinazzo, M. Panigati, M. Pappini, E. Quartapelle Procopio, S. Rizzo, Chemistry\u2010A European Journal 10, (2014), 15261 [3] S. Arnaboldi, P. Mussini, M. Magni, F. Sannicol\uf2, T. Benincori, R. Cirilli, K. Noworyta and W. Kutner, Chemical Science, 6 (2015), 170