The relationships of catalytic activity of metal Schiff base catalysts and the Hammett constants of their anion–cationic substituents on ligand

Chen, Hang; Liu, Jia; Yao, Jia; Hu, Jinghui; Chen, Kexian; Chen, Zhirong; Li, Haoran

doi:10.1002/poc.3451

Cited by 6 publications

(4 citation statements)

References 42 publications

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“…The plots show that ρ N has a reasonably strong linear correlation with respect to both field and the Hammett parameter. This is in accordance with the intended wide usage of the Hammett parameter in chemistry and is consistent with previous studies. ,, However, here, we take an additional step by studying ρ N with respect to an external field to allow linking external fields with the Hammett parameter. Following a similar approach as for the frequency data, ρ N can be fitted as a function of F and σ p , and the two resulting equations are correlated with each other and fitted to the following linear relation …”

Section: Discussionsupporting

confidence: 89%

“…This is in accordance with the intended wide usage of the Hammett parameter in chemistry and is consistent with previous studies. 4,9,14 However, here, we take an additional step by studying ρ N with respect to an external field to allow linking external fields with the Hammett parameter. Following a similar approach as for the frequency data, ρ N can be fitted as a function of F and σ p , and the two resulting equations are correlated with each other and fitted to the following linear relation σ = ± F 16 3 (MV/cm) p (8) Therefore, based on this method, one unit of Hammett parameter corresponds to about 16 MV/cm of polarizing external field.…”

Section: ■ Discussionmentioning

confidence: 99%

“…In this work, we consider the commonly used Hammett parameter σ p based on para-substituted benzoic acids. Both experimental and computational works show correlation between a substituent’s σ p value and an extraordinarily diverse range of chemical properties, including catalytic activity, photoacidity, photobasicity, π-conjugation strength in aromatic systems, even mechanical properties, and along with many others. − This general applicability justifies fundamental work to further understand its relation to other fields, in particular to electrochemistry.…”

Section: Hammett Parameters Interfacial Fields and Their Vibrational ...mentioning

confidence: 96%

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Electrodes as Polarizing Functional Groups: Correlation between Hammett Parameters and Electrochemical Polarization

et al. 2019

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Bridging the concepts of homogeneous and heterogeneous reactions is an important challenge in modern chemistry. Toward that end, here, we connect the homogeneous chemistry concept of the Hammett parameter, used by organic and organometallic chemists to quantify the electron-withdrawing capability of a functional group, to the electrochemical concept of polarization induced by a biased electrode. Because these two effects share similar origins, a theoretically motivated and experimentally verifiable link between them can be established. A convenient experiment that links the two is measuring the shift of vibrational frequency that is induced by these factors. To achieve this, first, we have measured the vibrational frequency of the nitrile stretch of 4-R-benzonitrile for a series of functional groups R spanning the Hammett parameter range −0.83 ≤ σp ≤ +1.11. Because the nitrile stretch is sensitive to molecular polarization, its frequency depends on the Hammett parameter of the polarizing functional groups. Second, we have measured the nitrile vibrational frequency of 4-mercaptobenzonitrile tethered on a gold electrode and polarized in an electrochemical cell as a function of potential from −1.4 to +0.6 V versus Ag/AgCl. Comparison of the nitrile-stretch frequency between the two experiments allows us to correlate the polarization caused by a functional group to that induced by the electrode. The data suggest equivalence between the Hammett parameter σp and the local electric field at the electrode interface, therefore allowing a polarizing electrode to be treated as a functional group. Computational work supports the experimental results and allows for a quantitative relation between the interfacial electric field and σp. We anticipate the benefits of this correlation, in particular, in linking concepts between homogeneous and heterogeneous reactions.

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Section: Discussionsupporting

confidence: 89%

Section: ■ Discussionmentioning

confidence: 99%

Section: Hammett Parameters Interfacial Fields and Their Vibrational ...mentioning

confidence: 96%

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Electrodes as Polarizing Functional Groups: Correlation between Hammett Parameters and Electrochemical Polarization

et al. 2019

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“…The resulting mixture was stirred at room temperature for 24 h. The reaction mixture was left to dry under air atmosphere and then under vacuum at room temperature. The produced precipitate was washed with distilled water yield (1.86 g, 71.8 %) [33].…”

Section: Synthesis Of Bis(3-chloro Acetylacetone) Ethylenediamine (An...mentioning

confidence: 99%

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2022

J. Med. Chem. Sci.

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In this work, the extraction of copper (II) by bis(3-chloro acetylacetone) ethylenediamine as a chelating reagent was studied by CPE using Triton X-100 as non-ionic surfactant and by solvent extraction using chloroform. Factors affecting extraction of copper (II) by both methods were studied such as equilibrium pH, effect of the ligand amounts, effect of equilibrium temperature, volume of solvent, and amount of non-ionic surfactant Triton X-100. K E Y W O R D SCopper ion Bis(3-chloro acetylacetone) ethylenediamine Cloud-point Solvent extraction

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Structure–reactivity landscape of N -hydroxyphthalimides with ionic-pair substituents as organocatalysts in aerobic oxidation

Chen

Yao

Chen

et al. 2015

Journal of Catalysis

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The relationships of catalytic activity of metal Schiff base catalysts and the Hammett constants of their anion–cationic substituents on ligand

Cited by 6 publications

References 42 publications

Electrodes as Polarizing Functional Groups: Correlation between Hammett Parameters and Electrochemical Polarization

Electrodes as Polarizing Functional Groups: Correlation between Hammett Parameters and Electrochemical Polarization

Untitled

Structure–reactivity landscape of N -hydroxyphthalimides with ionic-pair substituents as organocatalysts in aerobic oxidation

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