Poster presentado en la conferencia Electronic Structure Principles and Applications, Santiago de Compostela 2006

1. New Molecular Tweezers for Anion Recognition Jose M. Hermida Ramón and Carlos M. Estévez Department of Physical Chemistry. Facultade de Químicas. Universidade de Vigo. Goal = to design molecular tweezers with their MEP in the concave side more positive than the concave one, which can hold anions. Methods : DFT/6-31+G* geometry optimizations. Truhlar’s functional MPW1B95. 2 Counterpoise for BSSE on the complexes optimized geometries. Proposed molecular tweezer Complexation with halide anions Cl - Br - I -  E complex = -29.47 kcal mol -1 E deformation = 2.73 kcal mol -1  E complex = -26.45 kcal mol -1 E deformation = 2.79 kcal mol -1  E complex = -26.14 kcal mol -1 E deformation = 2.04 kcal mol -1 References: 1 Hermida-Ramón, J. M., Estévez, C.M.; ESPA2006 oral presentation. 2 Zhao, Y, Truhlar, D. G.; J.Phys. Chem. 108 (33): 6908-6918 2004 3 Klärner, F.-G., Kahlert, B.; Acc. Chem. Res. 36 (12): 919-932 2003 MEP in a.u. MEP in the molecular plane MEP in the center of the cavity Klärner´s molecular tweezers: can bind to electrodeficient molecules After fluorine substitution, can hold anions. 1 The MEP in the concave side is almost neutral and less positive than in the convex one. 1 I -  E complex , complexation energies (corrected for BSSE), slightly larger that the corresponding ones for cation complexes with Klärner´s molecular tweezers. 3 F O concave side MEP > convex side MEP