title: DFT studies of the conversion of four mesylate esters during reaction with ammonia.
abstract: The energetics of the Menshutkin-like reaction between four mesylate derivatives and ammonia have been computed using B3LYP functional with the 6-31+G** basis set. Additionally, MPW1K/6-31+G** level calculations were carried out to estimate activation barrier heights in the gas phase. Solvent effect corrections were computed using PCM/B3LYP/6-31+G** level. The conversion of the reactant complexes into ion pairs is accompanied by a strong energy decrease in the gas phase and in all solvents. The ion pairs are stabilized with two strong hydrogen bonds in the gas phase. The bifurcation at C2 causes a significant activation barrier increase. Also, bifurcation at C5 leads to noticeable barrier height differentiation. Both B3LYP/6-31+G** and MPW1K/6-31+G** activation barriers suggest the reaction 2 (2a + NH3) to be the fastest in the gas phase. The reaction 4 is the slowest one in all environments.
authors.affiliation: Faculty of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland. anowacki@chem.univ.gda.pl
authors.forename: Andrzej
authors.initials: A
authors.lastname: Nowacki
authors.forename: Karol
authors.initials: K
authors.lastname: Sikora
authors.forename: Barbara
authors.initials: B
authors.lastname: Dmochowska
authors.forename: Andrzej
authors.initials: A
authors.lastname: Wiśniewski
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D003198:Computer Simulation; D006860:Hydrogen Bonding; D008698:Mesylates / Q000737:chemistry*; D008956:Models, Chemical; D009005:Monosaccharides / Q000737:chemistry*; D011789:Quantum Theory; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013402:Sugar Alcohols / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D008698:Mesylates; D009005:Monosaccharides; D000644:Quaternary Ammonium Compounds; D013402:Sugar Alcohols; D014867:Water; D000641:Ammonia