Intermolecular interactions of 4-pyrrolidino pyridine: a simulation study

Simulations of intermolecular interaction by the AM1 method have been perfo rmed. The hydrogen bonding complex between and 4-pyrrolidino pyridine (PP) and water molecules with 1:n complexes have been considered to investigate possible stable complex configurations and to calculate the stable interact ion energy. These calculations confirm the influence of water molecules on twisting of the pyrrolidino group in ground state. The excited state simula tion predicts that the energy minimized geometry of the PP molecule takes a n almost sandwich like structure, confirming the formation of an intramolec ular exciplex in the gas phase as well as in nonpolar or in weakly polar so lvents in line with the experimental findings. (C) 1999 Elsevier Science B. V. All rights reserved.