title: A computational investigation of the geometrical structure and protodeboronation of boroglycine, H2N-CH2-B(OH)2.
abstract: In this article the geometrical structure of the simple, achiral, alpha-amino boronic acid boroglycine, H2N-CH2-B(OH)2, was investigated using density functional theory (DFT), second-order Møller-Plesset (MP2) perturbation theory, and coupled cluster methodology with single- and double-excitations (CCSD); the effects of an aqueous environment were incorporated into the results by using a few explicit water molecules and/or self-consistent reaction field (SCRF) calculations with the IEF polarizable continuum model (PCM). Neutral reaction mechanisms were investigated for the direct protodeboronation (hydrolysis) of boroglycine (H2O+H2N-CH2-B(OH)2-->B(OH)3+H2N-CH3), for which DeltaH degrees 298 was -21.9 kcal/mol at the MP2(FC)/aug-cc-pVDZ level, and for the 1,2-carbon-to-nitrogen shift of the -B(OH)2 moiety (H2N-CH2-B(OH)2-->H3C-NH-B(OH)2), for which the corresponding value of DeltaH degrees 298 was -18.2 kcal/mol. A boron-oxygen double-bonded intermediate was found to play an important role in the 1,2-rearrangement mechanism.
authors.affiliation: Department of Chemistry, Bloomsburg University of Pennsylvania, Bloomsburg, Pennsylvania 17815, USA. jlarkin@bloomu.edu
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Larkin
authors.forename: Krishna L
authors.initials: KL
authors.lastname: Bhat
authors.forename: George D
authors.initials: GD
authors.lastname: Markham
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Brooks
authors.forename: Jack H
authors.initials: JH
authors.lastname: Lai
authors.forename: Charles W
authors.initials: CW
authors.lastname: Bock
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D001897:Boronic Acids / Q000737:chemistry*; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry*; D006868:Hydrolysis; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D001896:Boron Compounds; D001897:Boronic Acids; C522272:boroglycine; D005998:Glycine