A theoretical investigation on the nature of the halogen bond through a valence-bond approach has been carried out with two main goals: (a) finding further confirmations of already existing explanations on the physical origins of the halogen bond and (b) possibly enriching the current models with new details. To achieve these goals we have exploited the spin-coupled method and we have performed computations on RBr⋯NH3 dimers characterized by a different electron withdrawing power of substituent R to the bromine atom. The analysis of typical spin-coupled descriptors (eg, shapes and overlaps of the spin-coupled orbitals, weights of the spin-coupled structures) in the different cases and in function of the distance between the monomers allowed us to draw qualitative conclusions about the formation and the strength of the halogen bonds. In particular, the investigation not only confirmed the validity of already existing models (ie, σ-hole and lump-hole models) but also highlighted interesting new features, such as the fact that the depletion of electron density around the bromine atom does not extend only toward the acceptor of the halogen bond, but also in the opposite direction (toward the substituent of the halogen), thus forming a sort of σ-tunnel, rather than a simple σ-hole.
A valence bond description of the bromine halogen bond / D. Franchini, A. Genoni, F. Dapiaggi, S. Pieraccini, M. Sironi. - In: INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY. - ISSN 0020-7608. - 119:15(2019 Aug 05).
|Titolo:||A valence bond description of the bromine halogen bond|
PIERACCINI, STEFANO (Penultimo)
|Parole Chiave:||halogen bond; spin-coupled; valence bond; σ-hole|
|Settore Scientifico Disciplinare:||Settore CHIM/02 - Chimica Fisica|
|Data di pubblicazione:||5-ago-2019|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1002/qua.25946|
|Appare nelle tipologie:||01 - Articolo su periodico|
File in questo prodotto:
|articolo_scxb.pdf||Post-print, accepted manuscript ecc. (versione accettata dall'editore)||Open Access Visualizza/Apri|
|Franchini_et_al-2019-International_Journal_of_Quantum_Chemistry.pdf||Publisher's version/PDF||Administrator Richiedi una copia|