Supramolecular structural design in a system based on nanocluster Mo-138 and a cationic surfactant: The influence of components ratio and pH of the solution

摘要

The design of supramolecular compounds is one of the key modern chemical trends. Based on the study of self-organising processes, supramolecular chemistry allows the creation of complex nanoclustered and hierarchical structures by the self-assembly method. We have investigated a system consisting of nanoclustered polyoxomolybdate Mo-138 with a toroid structure and cationic surfactant n-tridecylpyridinium chloride (TDPCh). As a result, the peculiarity of adsorptive interaction between system components was uncovered. This interaction depends on the components ratio and the pH of the solution and leads to spontaneous formation of hierarchical supramolecular structures. The sizes of ion-associates {(Mo-138)(x)-(TDPCh)(y)}, in solution and their zeta-potentials were determined by the dynamic light scattering method (DLS). Moreover, we have studied the extraction possibility of these ion-associates from water to organic solvents. The findings, together with the results of FTIR-spectroscopy, scanning probe, and electron microscopy, allowed us to make a model which describes the evolution of hierarchical structures in the system (Mo-138)-(n-tridecylpyridinium chloride) in conditions of increasing cationic surfactant concentration and changing pH. (C) 2015 Elsevier B.V. All rights reserved.