Bipolar behaviour of salt-bridges: a combined theoretical and crystallographic study. (26th June 2018)

• Record Type: Journal Article
• Authors: Seth, Saikat Kumar; Bauzá, Antonio; Frontera, Antonio
• Is Part Of: New journal of chemistry. Volume 42:Number 14(2018)
• Page Start: 12134
• Page End: 12142
• Publication Date: 2018-06-26
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c8nj02194e
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : In this manuscript, we study the bipolar behaviour of salt-bridges by combining theoretical calculations with an X-ray crystallographic study of succinate and aminopyridinium salts. Abstract : Crystal structures of aminopyridine–succinate salts (1–3 ) were solved by single crystal X-ray diffraction where salt bridge (SB) interactions between the succinate and protonated aminopyridine dominated their supramolecular architecture. X-ray crystallography reveals that compounds1 (hydrogensuccinate 2-amino-5-methylpyridinium salt) and2 (hydrogensuccinate 2-amino-4-methylpyridinium salt) exhibit C–H⋯SB⋯π + assemblies, while compound3 (succinato-aminopyridinium salt) displays unique N–H⋯SB⋯lone pair (l)p networks in the solid state. These unexplored extended networks are described and investigated for the first time in crystalline structures. Our study also describes the duality of the salt bridge in establishing π-facial interactions with electron rich and/or electron poor moieties depending on the positive or negative nature of the SB counterpart that interacts with the SB surface. The theoretical study combines an energetic investigation of the noncovalent forces that contribute to the extended supramolecular network and the characterization of the diverse interactions by means of Bader's theory of "atoms in molecules" (AIM) and the NCIplot index.