| Abstract
| - The complexation behavior, chirality induction and inversion in the achiral host, a racemic mixtureof ethane-bridged bis(zinc octaethylchlorin) (1), and optical activity modulation in the chiral hosts,enantiopure 1R and 1S, upon interaction with chiral and achiral amine guests have been investigatedby means of the UV−vis, CD, and 1H NMR techniques and compared with the corresponding spectraldata of the bis-porphyrin analogue. It was found that the chirogenesis pathway is strongly dependentupon the structures of both major components (hosts and guests) of these supramolecular systems.Particularly, the distinct orientation of electronic transitions in the chlorin chromophores arisenfrom the reduced pyrrole ring, which makes it radically different from that of the porphyrinchromophores, and the size of the guest's substituents lead to the remarkable phenomenon ofchirality induction-inversion in racemic 1 originating from the process of asymmetry transfer fromenantiopure guests of the same homologous type and absolute configuration. This surprisingchirogenic behavior is found to be in a sharp contrast to that observed in the analogous porphyrin-based systems. Furthermore, these structural and electronic phenomena also account for the effectiveoptical activity quenching of enantiopure 1R and 1S upon interaction with chiral and with achiralamines, which results in formation of supramolecular complexes of opposite chirality.
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