Protonation-Induced Conformational Changes of N,N,N′,N′-Tetramethylethylenediamine. Importance of Strong N–H+···N Hydrogen Bonding

Abstract

Abstract The effect of protonation on the conformation of N,N,N′,N′-tetramethylethylenediamine (TMEDA) has been studied by Raman spectroscopy and ab initio theory. TMEDA and TMEDAH22+ molecules assume predominantly the trans NC–CN conformation in aqueous solution, while a large number of TMEDAH+ molecules assume the gauche NC–CN conformation, as stabilized by strong intramolecular 1,4-N–H+···N hydrogen bonding.