Paola Peluso1, Alessandro Dessì1, Roberto Dallocchio1, Barbara Sechi1, Carlo Gatti2, Bezhan Chankvetadze3, Victor Mamane4, Robin Weiss4, Patrick Pale4, Emmanuel Aubert5, Sergio Cossu6. 1. Institute of Biomolecular Chemistry ICB, CNR, Secondary Branch of Sassari, Traversa La Crucca 3, Regione Baldinca, Li Punti, 07100 Sassari, Italy. 2. CNR-SCITEC, Istituto di Scienze e Tecnologie Chimiche "Giulio Natta", sezione di via Golgi, via C. Golgi 19, 20133 Milano, Italy. 3. Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, 0179 Tbilisi, Georgia. 4. Strasbourg Institute of Chemistry, UMR CNRS 7177, Team LASYROC, 1 rue Blaise Pascal, University of Strasbourg, 67008 Strasbourg CEDEX, France. 5. Crystallography, Magnetic Resonance and Modelling (CRM2), UMR CNRS 7036, University of Lorraine, Bd des Aiguillettes, 54506 Vandoeuvre-les-Nancy, France. 6. Department of Molecular Sciences and Nanosystems DSMN, Venice Ca' Foscari University, Via Torino 155, 30172 Mestre Venezia, Italy.
Abstract
The chalcogen bond (ChB) is a noncovalent interaction based on electrophilic features of regions of electron charge density depletion (σ-holes) located on bound atoms of group VI. The σ-holes of sulfur and heavy chalcogen atoms (Se, Te) (donors) can interact through their positive electrostatic potential (V) with nucleophilic partners such as lone pairs, π-clouds, and anions (acceptors). In the last few years, promising applications of ChBs in catalysis, crystal engineering, molecular biology, and supramolecular chemistry have been reported. Recently, we explored the high-performance liquid chromatography (HPLC) enantioseparation of fluorinated 3-arylthio-4,4'-bipyridines containing sulfur atoms as ChB donors. Following this study, herein we describe the comparative enantioseparation of three 5,5'-dibromo-2,2'-dichloro-3-selanyl-4,4'-bipyridines on polysaccharide-based chiral stationary phases (CSPs) aiming to understand function and potentialities of selenium σ-holes in the enantiodiscrimination process. The impact of the chalcogen substituent on enantioseparation was explored by using sulfur and non-chalcogen derivatives as reference substances for comparison. Our investigation also focused on the function of the perfluorinated aromatic ring as a π-hole donor recognition site. Thermodynamic quantities associated with the enantioseparation were derived from van't Hoff plots and local electron charge density of specific molecular regions of the interacting partners were inspected in terms of calculated V. On this basis, by correlating theoretical data and experimental results, the participation of ChBs and π-hole bonds in the enantiodiscrimination process was reasonably confirmed.
The pan class="Chemical">chalcogenn> bond (ChB) is a noncovalent intepan class="Disease">raction bapan class="Chemical">sed on electrophilic features of regions of electron charge density depletion (σ-holes) located on bound atoms of group VI. The σ-holes of sulfur and heavy chalcogen atoms (Se, Te) (donors) can interact through their positive electrostatic potential (V) with nucleophilic partners such as lone pairs, π-clouds, and anions (acceptors). In the last few years, promising applications of ChBs in catalysis, crystal engineering, molecular biology, and supramolecular chemistry have been reported. Recently, we explored the high-performance liquid chromatography (HPLC) enantioseparation of fluorinated 3-arylthio-4,4'-bipyridines containing sulfur atoms as ChB donors. Following this study, herein we describe the comparative enantioseparation of three 5,5'-dibromo-2,2'-dichloro-3-selanyl-4,4'-bipyridines on polysaccharide-based chiral stationary phases (CSPs) aiming to understand function and potentialities of selenium σ-holes in the enantiodiscrimination process. The impact of the chalcogen substituent on enantioseparation was explored by using sulfur and non-chalcogen derivatives as reference substances for comparison. Our investigation also focused on the function of the perfluorinated aromatic ring as a π-hole donor recognition site. Thermodynamic quantities associated with the enantioseparation were derived from van't Hoff plots and local electron charge density of specific molecular regions of the interacting partners were inspected in terms of calculated V. On this basis, by correlating theoretical data and experimental results, the participation of ChBs and π-hole bonds in the enantiodiscrimination process was reasonably confirmed.
Authors: Kamran T Mahmudov; Maximilian N Kopylovich; M Fátima C Guedes da Silva; Armando J L Pombeiro Journal: Dalton Trans Date: 2017-08-08 Impact factor: 4.390
Authors: L C Clark; G F Combs; B W Turnbull; E H Slate; D K Chalker; J Chow; L S Davis; R A Glover; G F Graham; E G Gross; A Krongrad; J L Lesher; H K Park; B B Sanders; C L Smith; J R Taylor Journal: JAMA Date: 1996-12-25 Impact factor: 56.272