Cooperativity in the stacking of benzene-1,3,5-tricarboxamide: The role of dispersion

Quantum chemical calculations have been carried out to study the stacking and cooperativity in oligomers of benzene-1,3,5-tricarboxamide (BTA). Comparison between density functional theory (DFT) and SCS-MP2/cc-PVTZ level calculations for a dimer indicates the significant contribution of dispersive interactions in this system. Oligomers up to a decamer have thus been studied with DFT augmented by empirical van der Waals corrections. The stabilisation energy of the stack improves with oligomer size and a converged value of -27.1 kcal/mol is estimated. The presence of cooperativity in the system is reflected in a variety of structural parameters of the stack. (C) 2011 Elsevier B.V. All rights reserved.