title: DFT studies of the formation of furanoid derivatives of ammonium chlorides.
abstract: B3LYP/6-31+G** level computations were performed on the formation of ammonium salts during the reaction of (S)-1,4-anhydro-5-chloro-2,3,5-trideoxypentitol (1) (2S,5S)-2,5-anhydro-6-chloro-1,3,4,6-tetradeoxyhexitol (2) and methyl 5-chloro-2,3,5-trideoxy-β-D-pentofuranoside (3) with ammonia in order to describe the reaction pathway in detail. All the structures were fully optimized in the gas phase, in chloroform and water. In addition, the gas phase activation barrier heights were estimated at B3LYP/6-311++G**, MPWIK/6-31+G**, MPWIK/6-311++G** and MP2/6-311++G(2d,2p)//MPWIK/6-31+G** levels of theory. All the calculations in solvents were performed the using polarizable continuum model (PCM) and the B3LYP functional with the 6-31+G** basis set. A detailed description of all the stationary points is presented, and the conformational behavior of the five-membered ring is discussed in the gas phase and in the solvents. The conversion of the reactant complexes into ion pairs is accompanied by a strong energy decrease in the gas phase and in all the solvents. The overall process is strongly unfavorable in the gas phase, but takes place readily in high-polarity solvents.
authors.affiliation: Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, PL-80-308 Gdańsk, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Wielińska
authors.affiliation: Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, PL-80-308 Gdańsk, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Liberek
authors.affiliation: Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, PL-80-308 Gdańsk, Poland. Electronic address: andrzej.nowacki@ug.edu.pl.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Nowacki
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry*; D002725:Chloroform / Q000737:chemistry*; D005663:Furans / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry; D055672:Static Electricity; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D064751:Ammonium Compounds; D005663:Furans; D005740:Gases; D012997:Solvents; D014867:Water; D002725:Chloroform
keywords: Ammonium salt, Hydrogen bond; DFT calculations; Furanoid ring conformation; NBO