Charge-Transfer-Induced Circular Dichroism CTICD

5 Charge-Transfer-Induced Circular Dichroism (CTICD) 

It is well known that intermolecular interactions between two organic compounds or organic and inorganic compounds give rise to a new absorption band(s), not present in the components. The new absorption band is characteristic of a loose reversible complex between an electron donor D and electron acceptor A, and ascribed to an electronic transition from D to A. The transition is called charge-transfer (CT) transition 53). 

If either D or A is optically active, the CT transition is expected to exhibit CD, because the optically active species perturbe the CT transition. Firstly, Briegleb 54) observed the CD of the electron donor-acceptor (EDA) complex of various kinds of optically active ketones with tetracyanoethylene (TCNE). He concluded that the CT and CD are attributable to the n- n transition, where n is the lone-pair orbital of the optically 

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