Trujillo, CristinaRodríguez Sanz, Ana AngustiasRozas, Isabel2020-05-202020-05-202015Trujillo, C.; Rodriguez-Sanz, A.A.; Rozas, I. Aromatic Amino Acids-Guanidinium Complexes through Cation-π Interactions. Molecules 2015, 20, 9214-9228http://hdl.handle.net/10347/22451Continuing with our interest in the guanidinium group and the different interactions than can establish, we have carried out a theoretical study of the complexes formed by this cation and the aromatic amino acids (phenylalanine, histidine, tryptophan and tyrosine) using DFT methods and PCM-water solvation. Both hydrogen bonds and cation-π interactions have been found upon complexation. These interactions have been characterized by means of the analysis of the molecular electron density using the Atoms-in-Molecules approach as well as the orbital interactions using the Natural Bond Orbital methodology. Finally, the effect that the cation-π and hydrogen bond interactions exert on the aromaticity of the corresponding amino acids has been evaluated by calculating the theoretical NICS values, finding that the aromatic character was not heavily modified upon complexationeng© 2015 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/)http://creativecommons.org/licenses/by/4.0/Guanidinium cationAromatic amino acidscation-π interactionsHydrogen bondNon-covalent interactionsAromaticityjournal article10.3390/molecules200592141420-3049open access