Phenyl Ring: A Steric Hindrance or a Source of Different Hydrogen Bonding Patterns in Self-Organizing Systems?

Abstract

A series of five alcohols (3-methyl-2-butanol, 1-cyclopropylethanol, 1-cyclopentylethanol, 1-cyclohexylethanol, and 1-phenylethanol) was used to study the impact of the size of steric hindrance and its aromaticity on self-assembling phenomena in the liquid phase. In this Letter, we have explicitly shown that the phenyl ring exerts a much stronger effect on the self-organization of molecules via the O–H···O scheme than any other type of steric hindrance, leading to a significant decline in the size and concentration of the H-bonded clusters. Given the combination of calorimetric, dielectric, infrared, and diffraction studies, this phenomenon was ascribed to its additional proton-acceptor function for the competitive intermolecular O–H···π interactions. The consequence of this is a different packing of molecules on the short- and medium-range scale.

Solvent Effect on Assembling and Interactions in Solutions of Phenol: Infrared Spectroscopic and Density Functional Theory Study

“…Nowok et al have shown that a phenyl ring has a much stronger effect on the self-assembling through the OHÁÁÁOH interactions than any other kind of steric hindrance. 15 This effect leads to the reduction in the size and population of the hydrogen-bonded associates. In addition, the phenyl ring is a source of OHÁÁÁp interactions, which compete with the OHÁÁÁOH ones.…”

“…Numerous studies reveal that the OHÁÁÁp interaction is an important factor affecting the assembling process of phenol and its derivatives in aromatic solvents. 8,[11][12][13][14][15][16][17][18][19][20] The strength of the OHÁÁÁp interactions depends on the number, position, and character of the substituents in the aromatic ring of the solute and solvent. IR studies by Saggu et al have shown that the electron withdrawing substituents weaken the OH(D)ÁÁÁp phenol-solvent interactions, while the electron donating groups have an opposite effect.…”

“…Numerous studies reveal that the OH···π interaction is an important factor affecting the assembling process of phenol and its derivatives in aromatic solvents. 8,11–20 The strength of the OH···π interactions depends on the number, position, and character of the substituents in the aromatic ring of the solute and solvent. IR studies by Saggu et al.…”

The water uptake, thermal and mechanical properties, and aging resistance to thermo‐oxidation of phenylboronic acid‐modified benzoxazine‐glass fiber composites

“…For example, Si O N for Bz/GF and PBz/GF that also has Si O B, and Si O C for PR and Si O B for PPR. 23 Finally, the hydrogen bonds (OH O) of Bz and (OH-π) of PBz 41,42 may further positively enhance their resin/GF interfacial adhesion. Bz-a and PBz 10-a in Figure 8 show increased ILSS by 21.1% but decreased ILSS by 28.5%, respectively.…”

“…8 Hence, an increased cross-linked density of the PBz 10 matrix and increased interfacial adhesion of PBz 10/GF as demonstrated by ILSS test can improve its flexural properties. On top of that, the steric hindrance induced by the dangling phenyl groups 41 in the phenylboronates of PBz 10 may help stabilize the network structure and contribute to an increased flexural properties. 8 In addition, PBz 15/GF also exhibits an increase by 5.2% and 6.4% in flexural strength and modulus compared to Bz/GF despite its deteriorated interfacial adhesion indicated by ILSS test.…”