Structural considerations for charge-enhanced Bronsted acid catalysts was written by Payne, Curtis;Kass, Steven R.. And the article was included in Journal of Physical Organic Chemistry in 2020.SDS of cas: 626-64-2 This article mentions the following:
All three N-methylated and N-protonated hydroxypyridinium BArF4– salt isomers were synthesized and their hydrogen bond donating abilities were investigated. DFT and G4 theory computations along with IR spectroscopic measurements were found to be effective methods for predicting the catalytic activities of these O-H and N-H Bronsted acids. A UV-vis titration approach for rapidly quantifying hydrogen bond donating ability revealed that carbon-hydrogen bonds also can participate in electrostatic interactions, but the presence of multiple equilibrium complexes results in a limitation of this method. In the methylated series of hydroxypyridines, the ortho and para isomers displayed modest rate enhancements relative to the meta derivative Protonation introduces a new acidic site and the ortho hydroxypyridinium ion salt is a significantly more active catalyst than all of the other species examined This is indicative of bidentate activation by the N-H and O-H acidic sites, and suggests a new design strategy for improving charge-enhanced catalysts. In the experiment, the researchers used many compounds, for example, Pyridin-4-ol (cas: 626-64-2SDS of cas: 626-64-2).
Pyridin-4-ol (cas: 626-64-2) belongs to pyridine derivatives. The ring atoms in the pyridine molecule are sp2-hybridized. The nitrogen is involved in the π-bonding aromatic system using its unhybridized p orbital. The lone pair is in an sp2 orbital, projecting outward from the ring in the same plane as the σ bonds. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.SDS of cas: 626-64-2