Meot-Ner, Michael et al. published their research in Journal of the American Chemical Society in 1983 | CAS: 644-98-4

2-Isopropylpyridine (cas: 644-98-4) 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. 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.Application In Synthesis of 2-Isopropylpyridine

The ionic hydrogen bond. 1. Sterically hindered bonds. Solvation and clustering of protonated amines and pyridines was written by Meot-Ner, Michael;Sieck, L. Wayne. And the article was included in Journal of the American Chemical Society in 1983.Application In Synthesis of 2-Isopropylpyridine This article mentions the following:

The gas-phase dissociation energy (determined for high-pressure mass spectra) of the homocongugates (R3N)2H+(I; R = Me, Et, Pr, Bu) and II (R = R1 = H, Me,Et, Me2CH, Me3C; R = H; R1 = Me, Me2CH, Me3C) and the corresponding hydrates (H2O heteroconjugates) R3N+H·H2O and III are steric effect independent. Steric hindrance to dimeric association or hydraton is reflected in large dissociation entropy (ΔS0) terms. The steric contribution to ΔS0 ranges up to 12, 17, and 19 cal mol-1 K-1 for I (R = Me2CH), I (R = Bu), and III (R = R1 = Me3C) (IV). The large steric entropy factor in IV is due to the simultaneous freezing of the rotations of both Me3C groups and of the H2O on hydration. A comparison of the gas-phase proton affinity with the organic basicity of hindered pyridines shows that steric hindrance to ion solvation in bulk H2O is comparable in magnitude to steric hindrance of solvation by only one H2O mol. The bond strength is not weakened by steric crowding when at least a single conformation exists in which the H-bond in homo- or heteroconjugates can obtain an optimal geometry. Steric crowding results in major entropy effects due to the hindrance of internal rotors in both homoconjugates and heteroconjugate monohydrates. In the experiment, the researchers used many compounds, for example, 2-Isopropylpyridine (cas: 644-98-4Application In Synthesis of 2-Isopropylpyridine).

2-Isopropylpyridine (cas: 644-98-4) 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. 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.Application In Synthesis of 2-Isopropylpyridine

Referemce:
Pyridine – Wikipedia,
Pyridine | C5H5N – PubChem