An NMR study of hydrogen-bonding in substituted phenols

Griffiths, V. S.; Socrates, G.

doi:10.1016/0022-2852(66)90153-6

Cited by 28 publications

(6 citation statements)

References 11 publications

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“…The possibility of a proportionality between ir and nmr shifts for hydrogen bonded species has been discussed. 24 It is interesting to note that the relative distances separating 3 and 8 from in Table XI are quite similar to the separation of the associated bands from the monomer band in the ir fundamental region.…”

Section: Results Calculations and Discussionsupporting

confidence: 54%

Association of methanol in vapor and in n-hexadecane. A model for the association of alcohols

Tucker¹,

Farnham²,

Christian³

1969

J. Phys. Chem.

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Section: Results Calculations and Discussionsupporting

confidence: 54%

Association of methanol in vapor and in n-hexadecane. A model for the association of alcohols

Tucker¹,

Farnham²,

Christian³

1969

J. Phys. Chem.

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“…This concentration dependence was attributed to a monomer-trimer equilibrium. 25,44 We measured the 1 H spectrum of phenol from 1 to 100 mg/ml (³0.01 1 M) in CDCl 3 . Again, the OH shift is linear with concentration Eqn (1) Fig.…”

Section: Nmr Spectramentioning

confidence: 99%

An NMR, IR and theoretical investigation of ¹H Chemical Shifts and hydrogen bonding in phenols

Abraham

Mobli

2007

Magnetic Reson in Chemistry

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The change in (1)H NMR chemical shifts upon hydrogen bonding was investigated using both experimental and theoretical methods. The (1)H NMR spectra of a number of phenols were recorded in CDCl(3) and DMSO solvents. For phenol, 2- and 4-cyanophenol and 2-nitrophenol the OH chemical shifts were measured as a function of concentration in CDCl(3). The plots were all linear with concentration, the gradients varying from 0.940 (phenol) to 7.85 (4-cyanophenol) ppm/M because of competing inter- and intramolecular hydrogen bonding. Ab initio calculations of a model acetone/phenol system showed that the OH shielding was linear with the H...O=C distance (R) for R < 2.1 A with a shielding coefficient of - 7.8 ppm/A and proportional to cos(2)phi where phi is the H...O=C--C dihedral angle. Other geometrical parameters had little effect. It was also found that the nuclear shielding profile is unrelated to the hydrogen bonding energy profile. The dependence of the OH chemical shift on the pi density on the oxygen atom was determined as ca 40 ppm/pi electron. This factor is similar to that for NH but four times the value for sp(2) hybridized carbon atoms. The introduction of these effects into the CHARGE programme allowed the calculation of the (1)H chemical shifts of the compounds studied. The CHARGE calculations were compared with those from the ACD database and from GIAO calculations. The CHARGE calculations were more accurate than other calculations both when all the shifts were considered and also when the OH shifts were excluded. The calculations from the ACD and GIAO approaches were reasonable when the OH shifts were excluded but not as good when all the shifts were considered. The poor treatment of the OH shifts in the GIAO calculations is very likely due to the lack of explicit solvent effects in these calculations.

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“…The 1 H NMR spectrum of the BPN ionomer obtained from the post-mortem anode catalyst layer after this durability test showed no changes in the characteristic peaks except for a small and broad new peak centered at 5.75 ppm, which was assigned to the phenolic proton (Figure 1b). The relatively high chemical shift of the phenolic proton peak compared to that in nonsubstituted phenol 23 suggests that the oxidation occurred on the aryl protons in the four ortho-positions to biphenyl as depicted by the * in Figure 1b inset. Identical peaks in the saturated hydrocarbon peaks suggest that little oxidation of alkyl groups, if any, occurred.…”

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Phenyl Oxidation Impacts the Durability of Alkaline Membrane Water Electrolyzer

Matanović

Lee

et al. 2019

ACS Appl. Mater. Interfaces

117

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The durability of alkaline anion exchange membrane (AEM) electrolyzers is a critical requirement for implementing this technology in cost-effective hydrogen production. Here, we report that the electrochemical oxidation of the adsorbed phenyl group (found in the ionomer) on oxygen evolution catalysts produces phenol, which may cause performance deterioration in AEM electrolyzers. In-line 1H NMR kinetic analyses of phenyl oxidation in a model organic cation electrolyte shows that catalyst type significantly impacts the phenyl oxidation rate at an oxygen evolution potential. Density functional theory calculations show that the phenyl adsorption is a critical factor determining the phenyl oxidation. This research provides a path for the development of more durable AEM electrolyzers with components that can minimize the adverse impact induced by the phenyl group oxidation, such as the development of novel ionomers with fewer phenyl moieties or catalysts with less phenyl-adsorbing character.

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An NMR study of hydrogen-bonding in substituted phenols

Cited by 28 publications

References 11 publications

Association of methanol in vapor and in n-hexadecane. A model for the association of alcohols

Association of methanol in vapor and in n-hexadecane. A model for the association of alcohols

An NMR, IR and theoretical investigation of ¹H Chemical Shifts and hydrogen bonding in phenols

Phenyl Oxidation Impacts the Durability of Alkaline Membrane Water Electrolyzer

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An NMR study of hydrogen-bonding in substituted phenols

Cited by 28 publications

References 11 publications

Association of methanol in vapor and in n-hexadecane. A model for the association of alcohols

Association of methanol in vapor and in n-hexadecane. A model for the association of alcohols

An NMR, IR and theoretical investigation of 1H Chemical Shifts and hydrogen bonding in phenols

Phenyl Oxidation Impacts the Durability of Alkaline Membrane Water Electrolyzer

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An NMR, IR and theoretical investigation of ¹H Chemical Shifts and hydrogen bonding in phenols