Artículo
Shared Hydrogen Atom Location and Chemical Composition in Picolinic Acid and Pyridoxal Hydrochloride Derivatives Determined by X-ray Crystallography
Crespi, Ayelen Florencia
; Vega, Daniel Roberto; Sanchez, Veronica Muriel
; Rodríguez Castellón, Enrique; Lazaro Martinez, Juan Manuel
Fecha de publicación:
09/2022
Editorial:
American Chemical Society
Revista:
Journal of Organic Chemistry
ISSN:
0022-3263
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Three new single-crystal structures were isolated for picolinic acid (2), the trifluoroacetate salt of picolinic acid (1), andpyridoxal hydrochloride (3). These compounds displayed unconventional crystallographic features that must be consideredwhen structural refinements are carried out. Thus, the generated Fourier differences map obtained with the diffraction datacollected at 100 K was crucial to visualize electron densities, which were balanced by either one hydrogen atom or a hydrogen atom with an occupancy factor of 1/2 located between either two carboxylate moieties, two phenolic oxygen atoms, or two pyridinic nitrogen atoms. Moreover, NMR studies were conducted to analyze the bulk chemical composition of single crystals of 2-pyridinecarboxylic acid obtained from the gem-diol/hemiacetal forms and the polymerization products after the treatment of 2-pyridinecarboxaldehyde with TFA:H2O (1) or a diluted Cu(NO3)2 solution (2). The quantitative yield of the pyridoxal hydrochloride crystalline material (3) obtained from a diluted CuCl2 solution was exhaustively characterized by solid-state NMR methods. These methods allowed the resolution of the signals corresponding to the protons of the hydroxyl moiety of the intramolecular hemiacetal group and the phenolic hydrogen. Theoretical calculations using DFT methods were done to complement the atomic location of the hydrogen atoms obtained from the X-ray analysis.
Palabras clave:
X-RAY CRYSTALLOGRAPHY
,
NUCLEAR MAGNETIC RESONANCE
,
DFT
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Articulos(CETMIC)
Articulos de CENTRO TECNOL.DE REC.MINERALES Y CERAMICA (I)
Articulos de CENTRO TECNOL.DE REC.MINERALES Y CERAMICA (I)
Articulos(INQUIMAE)
Articulos de INST.D/QUIM FIS D/L MATERIALES MEDIOAMB Y ENERGIA
Articulos de INST.D/QUIM FIS D/L MATERIALES MEDIOAMB Y ENERGIA
Articulos(IQUIMEFA)
Articulos de INST.QUIMICA Y METABOLISMO DEL FARMACO (I)
Articulos de INST.QUIMICA Y METABOLISMO DEL FARMACO (I)
Citación
Crespi, Ayelen Florencia; Vega, Daniel Roberto; Sanchez, Veronica Muriel; Rodríguez Castellón, Enrique; Lazaro Martinez, Juan Manuel; Shared Hydrogen Atom Location and Chemical Composition in Picolinic Acid and Pyridoxal Hydrochloride Derivatives Determined by X-ray Crystallography; American Chemical Society; Journal of Organic Chemistry; 87; 20; 9-2022; 13427-13438
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