Matrix effects on hydrogen bonding and proton transfer in fluoropyridine – HCl complexes was written by Soares, Camilla;Ley, Anna R.;Zehner, Brittany C.;Treacy, Patrick W.;Phillips, James A.. And the article was included in Physical Chemistry Chemical Physics in 2022.SDS of cas: 700-16-3 The following contents are mentioned in the article:
We report an extensive computational and spectroscopic study of several fluoropyridine-HCl complexes, and the parent, pyridine-HCl system. Matrix-IR spectra for pentafluoropyridine-HCl, 2,6-difluororpyridine-HCl, and 3,5-difluororpyridine-HCl in solid neon exhibit shifts for the H-Cl stretching band that parallel the effects of fluorination on hydrogen-bond strength. Analogous spectral shifts observed across various host environments (solid neon, argon, and nitrogen) for pentafluoropyridine-HCl and 2,6-difluororpyridine-HCl convey a systematically varying degree of matrix stabilization on the hydrogen bonds in these complexes. An extended quantum-chem. study of pyridine-HCl and eight fluorinated analogs, including 2-, 3-, and 4-fluoropyridine-HCl, 2,6- and 3,5-difluororpyridine-HCl, 2,4,6- and 3,4,5-trifluropyridine-HCl, as well as pentafluoropyridine-HCl, was also performed. Equilibrium structures and binding energies for the gas-phase complexes illustrate two clear trends in how fluorine substitution affects hydrogen bond strength; increasing fluorination weakens these interactions, yet substitution at the 2- and 6-positions has the most pronounced effect. Bonding analyses for a select subset of these systems reveal shifts in electron d. that accompany hydrogen bonding, and most notably, the values of the electron d. at the N-H bond critical points among the stronger systems in this subset significantly exceed those typical for moderately strong hydrogen-bonds. We also explored the effects of dielec. media on the structural and bonding properties of these systems. For pyridine-HCl, 3-fluoropyridine-HCl, and 3,5-difluororpyridine-HCl, a transition to proton transfer-type structures is observed at ε-values of 1.2, 1.5, and 2.0, resp. This is signaled by key structural changes, as well as an increase in the neg. charge on the chorine, and dramatic shifts in topol. properties of the H-Cl and N-H bonds. In the case of pentafluoropyridine-HCl, and 2,6-difluororpyridine-HCl, we do not predict proton transfer in dielec. media up to ε = 20.0. However, there are clear indications that the media enhance hydrogen-bond strength, and moreover, these observations are completely consistent with the exptl. IR spectra. This study involved multiple reactions and reactants, such as 2,3,4,5,6-Perfluoropyridine (cas: 700-16-3SDS of cas: 700-16-3).
2,3,4,5,6-Perfluoropyridine (cas: 700-16-3) belongs to pyridine derivatives. In contrast to benzene, Pyridine’s electron density is not evenly distributed over the ring, reflecting the negative inductive effect of the nitrogen atom. Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B3) occurs in some bacteria, fungi, and mammals.SDS of cas: 700-16-3