Spectroscopic, Conductivity and Molecular Modeling Studies of the Inclusion Complex of TNDAB with Cucurbit[7]uril in Aqueous Solution

Abstract

Abstract In this investigation, a novel surfactant (N, N, N-trimethyl-4-(5-decyloxy naphthalene-1-yloxy) butan-1-aminium bromide, TNDAB) with a naphthalene chromophore moiety was synthesized. The UV, fluorescence, conductivity measurements and molecular modeling have been carried out at 298 K for TNDAB + H2O, and TNDAB + CB[7] + H2O systems. The apparent critical micelle concentrations, the dissociation degree of the micelle, the hydrophobic contribution of the transfer free energy for the hydrocarbon chain of TNDAB, and the stoichoimetry, stability constant, and potential energy surface for the inclusion complex of TNDAB and CB[7] have been determined. The results suggested that CB[7] formed strong complex with TNDAB, the stoichoimetry of CB[7] and TNDAB was found to be almost 1:1, and hydrophobic interactions between the naphthalene nucleus of TNDAB and the cavity of the CB[7] are suggested to be the main driving forces in the association process. It also indicated that the naphthalene chromophore introduced can be as a spectral probe to examine the inclusion behaviors between host and guest molecules.