Fluorescence characteristics of Schiff base-N,N′-bis(salicylidene) trans 1,2-diaminocyclohexane in the presence of bile acid host

Understanding the formation of bile acid micellar aggregates is of great importance due to its wide biological and pharmacological applications. In this paper, we study the fluorescence properties of Schiff base-N,N'-bis(salicylidene) trans 1,2-diaminocyclohexane (H2L) to understand micelle formation by aggregation of different important bile acids - cholic acid, deoxycholic acid, chenodeoxycholic acid and glycocholic acid by steady state and picosecond time-resolved fluorescence spectroscopy. The fluorescence band intensity was found to increase with concomitant blue shift with gradual addition of different bile acids. Several mean microscopic properties such as critical micelle concentration, polarity parameters and binding constant were estimated in the presence of bile acids. The increase in fluorescence quantum yields, fluorescence decay times and substantial decrease in nonradiative decay rate constants in bile acid micellar environment points to the restricted motion of the fluorophore inside the micellar subdomains. (C) 2015 Elsevier B.V. All rights reserved.