Dulal Chandra Mukherjee

Absorption spectra of tetrahaloquinone-aza-aromatic systems

Abstract The characteristic charge transfer absorption bands of a number of aza-aromatics as donors with chloranil, bromanil and iodanil as acceptors have been measured in chloroform solution in the ultraviolet and visible regions. The bands in the ultraviolet and visible regions are attributed respectively to the charge transfer transition of π electron and n electron of donors to the vacant orbital of the acceptors. A number of more or less sharp bands presumed to be due to the singlet → triplet transition in donors has been observed in some cases with bromanil and iodanil.

Study of charge transfer complexes of menadione (vitamin K3) with a series of anilines

Menadione (vitamin K(3)) has been shown to form charge transfer complexes with N,N-dimethyl aniline, N,N-dimethyl p-toluidine and N,N-dimethyl m-toluidine in CCl(4) medium. The CT transition energies are well correlated with the ionisation potentials of the anilines. The formation constants of the complexes have been determined at a number of temperatures from which the enthalpies and entropies of formation have been obtained. The formation constants exhibit a very good linear free energy relationship (Hammett) at all the temperatures studied.