title: Aromatic Amino Acids-Guanidinium Complexes through Cation-π Interactions.
abstract: Continuing 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 complexation.
authors.affiliation: Trinity Biomedical Sciences Institute, School of Chemistry, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland. trujillc@tcd.ie.
authors.forename: Cristina
authors.initials: C
authors.lastname: Trujillo
authors.affiliation: Departamento de Química Física, Facultade de Ciencias, Universidade de Santiago de Compostela, Campus de Lugo, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain. anaangustias.rodriguez@usc.es.
authors.forename: Ana A
authors.initials: AA
authors.lastname: Rodriguez-Sanz
authors.affiliation: Trinity Biomedical Sciences Institute, School of Chemistry, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland. rozasi@tcd.ie.
authors.forename: Isabel
authors.initials: I
authors.lastname: Rozas
mesh_terms: D024322:Amino Acids, Aromatic / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry* / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D013816:Thermodynamics
chemical_list: D024322:Amino Acids, Aromatic; D002412:Cations; D019791:Guanidine
keywords: aromatic amino acids; aromaticity; cation-π interactions; guanidinium cation; hydrogen bond; non-covalent interactions