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Computational study on the characteristics of the interaction in linear urea clusters
Author(s) -
Esrafili Mehdi D.,
Beheshtian Javad,
Hadipour Nasser L.
Publication year - 2011
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.22628
Subject(s) - chemistry , hydrogen bond , cooperativity , interaction energy , dimer , perturbation theory (quantum mechanics) , urea , computational chemistry , coupled cluster , natural bond orbital , binding energy , atomic physics , molecule , density functional theory , quantum mechanics , physics , organic chemistry , biochemistry
Quantum mechanics calculations were applied to investigate the NH ··· O hydrogen bonding properties in linear (urea) n =1–10 clusters. We investigated geometries, binding energies, and 17 O chemical shielding tensors of urea clusters, by means of MP2 and DFT methods. The charge‐transfer character of the urea clusters was estimated using Natural Bonding Orbital characteristics. It was found that the cooperativity effects enhance significantly the NH ··· O hydrogen bond from −33.08 (dimer) to −47.67 kJ/mol (decamer). The n ‐dependent trend of 17 O shielding tensors was reasonably correlated with cooperative effects in r CO bond distance. To deepen the nature of the interaction in urea clusters, the scheme of decomposition of the interaction energies was applied using Morokuma analysis and a variant of symmetry‐adapted perturbation theory (SAPT) based on DFT description of monomers, referred to as SAPT‐DFT. The SAPT‐DFT analysis of the interaction energy components indicates that the electrostatic and dispersive interactions are the most important attractive terms in the urea dimer. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011