Probing Molecular Chirality Using Metallo-Bisporphyrin Hosts

Supramolecular chirogenesis is one of the most important interdisciplinary field to be looked into, because of its occurrences in many natural (DNA double helix, heme proteins, secondary α-helix structure of proteins etc.) and artificial systems. Although, chiroptical spectroscopy such as Circular Dichroism (CD) is inherently sensitive to chirality, it has not enjoyed tremendous use as a method for stereochemical determinations, mainly because the results of CD analysis are empirical. Exciton Coupled Circular Dichroism (ECCD) is a nonempirical spectroscopic method that is based on detecting the through-space exciton interaction between helically orientated independently conjugated chromophores. The relative orientation of the two chromophores in space results in a predicted sign of the couplet; i.e., a clockwise orientation of two interacting chromophores yields a positive couplet and vice versa. Therefore, the challenge lies in orienting two or more chromophoric receptor groups in a chiral fashion as a direct result of the binding of a chiral compound and extrapolating the chirality of the bound compound from the ECCD spectra. This presentation will showcase some of our recent research activity along the line.

Representative referances:

1. S. A. Ikbal, S. Brahma, S. P. Rath Chem. Commun. 2014, 50, 14037-14040.
2. S. A. Ikbal, S. Brahma, S. P. Rath Chem. Commun. 2014, 50, ASAP. (DOI: 10.1039/c4cc07955h)

1. S. Brahma, S. A. Ikbal, S P Rath Inorg. Chem. 2014, 53, 2381-2395.
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5. S. Brahma, S. A. Ikbal, S. P. Rath Chem. Commun. 2012, 48, 4070-4072.