Cluster Quantum Chemical Study of Triaminotoluene Interaction with a Model Clay Surface

This paper presents the results of an ab initio cluster quantum chemical study at the HF/6-31G level for the triaminotoluene (TAT) molecule interaction with a model clay surface, in particular, a kaolinite-type clay mineral. The latter is characterized by a layer structure that contains three different structure units corresponding to alumina, silica, and an intersection of alumina-silica. According to the obtained results, the physical adsorption of TAT took place both on alumina and silica structure units. In going from silica to alumina-silica units, the two-center adsorption of TAT will result in strong adsorption via formation of a TATH⁺ species stabilized by two strong H bonds. Different channels of interactions of TAT with kaolinite-type clay surfaces (i.e., one-, two-, and three-center adsorption of TAT, an aromatic six-member ring opening of TAT) and its destruction via breaking the methyl-aromatic or amino-aromatic ring bonds are also discussed.