Variable-temperature neutron diffraction studies of the short, strong hydrogen bonds in the crystal structure of pyridine-3,5-dicarboxylic acid

Abstract

Pyridine-3,5-dicarboxylic acid has been studied by single-crystal neutron diffraction at 15 and 296 K. Pyridine-3,5-dicarboxylic acid, in which the carboxylic acid protons have been replaced by deuterons, has also been studied at 15, 150 and 296 K. The protonated structure contains a short N...H...O hydrogen bond [N...O 2.523 (2) Angstrom at 15 K]. Temperature-dependent proton migration occurs where the N--H distance in the hydrogen bond changes from 1.213 (4) Angstrom at 15 K to 1.308 (6) Angstrom at 300 K. In the deuterated structure the overall hydrogen-bond length increased [N...O 2.538 (3) Angstrom at 15 K] and the magnitude of the migration increased so that the N--D distance changes from 1.151 (3) Angstrom at 15 K to 1.457 (4) Angstrom at 300 K.

Raman and infrared spectra and theoretical calculations of dipicolinic acid, dinicotinic acid, and their dianions

“…This results in some asymmetry of the individual molecules which have nearly C 2v symmetry. A recent neutron diffraction study by Cowan and co-workers [13] is consistent with these results.…”

Phonon driven proton transfer in crystals with short strong hydrogen bonds

“…The structure of pyridine-3,5-dicarboxylic acid was reported at a number of temperatures in the range of 15-296 K by Cowan 8 and Cowan et al 9 PDA crystallizes in the P2 1 / c space group with four molecules in the unit cell. One short strong N1-H5¯O4 and a "normal" O-H¯O hydrogen bond link the molecules in two-dimensional planar sheets in the a-b plane.…”

Synthesis, Structure, and Magnetic Properties of New Spin Crossover Fe(II) Complexes Forming Short Hydrogen Bonds with Substituted Dicarboxylic Acids

“…The molecular arrangement shows that a zig-zag chain was formed with an alternating arrangement of Fe(II) complexes and H 2 Cl 2 TPA molecules via hydrogen bonds formed between the N atom in the terminal Py ring in the Fe(II) complex and a carboxyl group in H 2 Cl 2 TPA (Figure 1b). The N4···O3 hydrogen bond distance in the terminal pyridine ring was relatively long (N4···O3 = 2.663 Å), whereas the N8···O5 hydrogen bond distance was relatively short (N8···O5 = 2.552 Å) at 123 K. The N4···O3 and N8···O5 hydrogen bond distances in 1-Br were slightly longer (N4···O3 = 2.681 Å, N8···O5 = 2.560 Å) than those in 1-Cl at 123 K. The N8···O5 bond distances in 1-Cl and 1-Br were short for a N···O-type hydrogen bond but slightly longer than those commonly observed in organic compounds that exhibit proton migration induced by temperature change [13][14][15]. Regarding the temperature dependency of hydrogen bond distances, studies have reported that the hydrogen bond distance between the Py ring in isonicotinic acid hydrazide, a precursor of L, and the carboxyl group tends to increase with increasing temperature [16][17][18].…”

“…As shown in Figure 1a, the asymmetric unit of 1-Cl comprises one Fe(II) complex and one H2Cl2TPA molecule. The molecular arrangement shows that a zig-zag chain was formed with an alternating arrangement of Fe(II) complexes and H2Cl2TPA molecules via hydrogen bonds formed between the N atom in the terminal Py ring in the Fe(II) complex and a carboxyl group in H2Cl2TPA (Figure 1b [13][14][15]. Regarding the temperature dependency of hydrogen bond distances, studies have reported that the hydrogen bond distance …”