Experimental and Theoretical Charge Density Analysis of a Bromoethyl Sulfonium Salt

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2013-12, Vol.117 (51), p.14267-14275
• Main Authors: Ahmed, Maqsood, Yar, Muhammad, Nassour, Ayoub, Guillot, Benoit, Lecomte, Claude, Jelsch, Christian
• Format: Article
• Language: English
• Subjects: Atomic and molecular physics; Carbon; Charge density; Chemical bonds; Chemical Sciences; Condensed matter: structure, mechanical and thermal properties; Covalent bonds; Cristallography; Crystallography, X-Ray; Effects of atomic and molecular interactions on electronic structure; Electronic structure of atoms, molecules and their ions: theory; Electrostatics; Exact sciences and technology; Heterocyclic Compounds, 4 or More Rings - chemical synthesis; Hydrocarbons, Brominated - chemistry; Mesylates - chemistry; Molecular solids; Molecular Structure; Organic chemistry; Organic compounds; Physics; Quantum Theory; Static Electricity; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Sulfonium Compounds - chemistry; Sulfur; Thermodynamics; Topology
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp410301d

Bromoethyl sulfonium trifluoromethanesulfonate is a salt complex in which a sulfur atom makes three covalent bonds. This molecule has been proved to act as an efficient annulation reagent which results in formation of synthetically challenging and pharmaceutically important 4-, 5-, 6-, and 7-membered heterocycles in excellent yields. The charge density of the molecule was determined from both experimentally and theoretically derived diffraction data. The stereochemistry and electron density topology of the sulfonium group was analyzed. To understand the chemical reactivity of the molecule, the electrostatic potential difference between the two carbon atoms of the bromoethyl group was investigated. It has been considered that the hydrogen atoms on the carbon atom bound to sulfur are more acidic in character due to their vicinity with the triply covalently bonded positively charged sulfur atom. The electropositivity of the S-attached and Br-attached methylene groups are compared in the experimental and theoretical charge densities using topological atomic charges and electrostatic potential at the molecular surface.