Calix[4]pyrrole based scrupulous probe for track on of tryptophan: Host-guest interaction, in silico modeling and molecular docking insights

Interaction of a novel calix[4]pyrrole bearing carboxylic acid functionality (ABCP) has been investigated towards amino acids in methanol. The ABCP-Tryptophan complex produces a blue shift in absorption spectra based on charge transfer mediated recognition. Additionally, the density functional theory calculations could substantiate possible mechanism for the 1:1 binding of Tryptophan with ABCP theoretically. Moreover, other parameters such as stability, softness, hardness and chemical potential have been calculated to know about the binding behaviour of ABCP as host and Tryptophan as guest. The Natural Bond Orbital and TDDFT calculation facilitates to understand the proper binding mechanism in reference to experimental results.