Potentiometric titration of metal ions in methanol

Gibson, Graham T. T.; Neverov, Alexei A.; Brown, R. S.

doi:10.1139/v03-035

Cited by 46 publications

(65 citation statements)

References 17 publications

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“…The CH 3 OH 2 + concentrations were determined potentiometrically using a combination glass electrode (Radiometer model XC100‐111‐120‐161) Fisher Scientific, Pittsburgh, PA, USA calibrated with certified standard aqueous buffers (pH = 4.00 and 10.00) as previously described . The

{}_{s}^{s}p K

values in methanol were obtained by subtracting a correction constant of −2.24 from the electrode readings.…”

Section: Methodsmentioning

confidence: 99%

Experimental and computational determination of Brønsted coefficients for equilibrium transfer of the O,O‐dimethyl phosphorothioyl group between oxyanion nucleophiles

Edwards

Maxwell

Harkness

et al. 2011

J of Physical Organic Chem

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An experimental determination of the β Eq value for equilibrium transfer of the O,O-dimethyl phosphorothioyl group between oxyanion nucleophiles in water and methanol at 25 C is presented. The respective β Eq values in the two solvents are experimentally the same at À1.45AE0.08 and À1.39AE0.12. Based on the observation that the Brønsted correlation for the nucleophilic reaction of phenoxides in water with substrate 1d (dimethyl 4-nitrophenyl phosphorothioate, pK a HOAr of 7.14) is linear over the entire range of phenoxides employed (5.53≤pK a Nu ≤12.38), the reaction for phenoxide nucleophiles displacing phenoxide leaving groups is probably concerted. The obtained data allow one to calculate, for a symmetrical transition state involving 2,4,5-trichlorophenoxide as a nucleophile and leaving group, an approximately 60% P-OAr cleavage and about 40% P-Nuc bond formation. A computational method is presented for the rapid prediction of the β Eq values for such processes in water and methanol, and the results are compared with known values from the literature.

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{}_{s}^{s}p K

values in methanol were obtained by subtracting a correction constant of −2.24 from the electrode readings.…”

Section: Methodsmentioning

confidence: 99%

Experimental and computational determination of Brønsted coefficients for equilibrium transfer of the O,O‐dimethyl phosphorothioyl group between oxyanion nucleophiles

Edwards

Maxwell

Harkness

et al. 2011

J of Physical Organic Chem

View full text Add to dashboard Cite

show abstract

“…The CH 3 OH 2 + concentrations were determined potentiometrically using a combination glass electrode calibrated with Fisher certified standard aqueous buffers (pH 4.00 and 10.00) as described previously. 50 The

{}_{s}^{s}{p H}

values 51 in methanol were obtained by subtracting a correction constant of -2.24 from the electrode readings with the autoprotolysis constant for methanol taken as 10 −16.77 M 2 .…”

Section: Methodsmentioning

confidence: 99%

Tryptophan-based fluorophores for studying protein conformational changes

Talukder

Chen

Liu

et al. 2014

Bioorganic & Medicinal Chemistry

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With the continuing interest in deciphering the interplay between protein function and conformational changes, small fluorescence probes will be especially useful for tracking changes in the crowded protein interior space. Presently, we describe the potential utility of six unnatural amino acid fluorescence donors structurally related to tryptophan and show how they can be efficiently incorporated into a protein as fluorescence probes. We also examine the various photophysical properties of the new Trp analogues, which are significantly redshifted in their fluorescence spectra relative to tryptophan. In general, the Trp analogues were well tolerated when inserted into E. coli DHFR, and did not perturb enzyme activity, although substitution for Trp22 did result in a diminution in DHFR activity. Further, it was demonstrated that D and E at position 37 formed efficient FRET pairs with acridon-2-ylalanine (Acd) at position 17. The same was also true for a DHFR construct containing E at position 79 and Acd at position 17. Together, these findings demonstrate that these tryptophan analogues can be introduced into DHFR with minimal disruption of function, and that they can be employed for the selective study of targeted conformational or electrostatic changes in proteins, even in the presence of unmodified tryptophans.

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“…The hydrolysis of phosphoester pesticide and CW agents using metal ions also inspired numerous studies. Interestingly although all the Ln ions, the best being La 3+ , show some activity in ethanolysis of paraoxon, none of them catalyzes similar hydrolysis of P=S derivative fenitrothion . Instead two of the softer transition metal ions (Zn 2+ and Cu 2+ ) promoted the latter reaction well, probably because they are “softer” in the Pearson “hard soft” sense .…”

Section: Aqueous Ions For Mimicking Phosphatases and Nucleasesmentioning

confidence: 99%

From DNA to Nerve Agents – The Biomimetic Catalysts for the Hydrolysis of Phosphate Esters

et al. 2020

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The phosphate ester bonds are widely present in living organisms and in the environment. From the nucleic acids to the sparingly dispersed pesticides and chemical warfare residues, the phosphoester bond's stability against hydrolysis can be extremely high or exceptionally low. Recently, the enzyme-mimicking nanomaterials, namely 'nanozyme', have been explored for their activities in hydrolytically cleaving DNA, organophosphate and their analogues. Herein in a broad perspective these nanomaterials were summarized and compared with a view to reproducing the catalysis efficiency and selectivity of natural phosphatases and nucleases. The development of biomimetic inorganic materials would not only provide potential nanomedicine for future gene editing, but also offer alternative solutions to the environmentally friendly treatment of pesticide residues and chemical warfare stockpiles.

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Potentiometric titration of metal ions in methanol

Cited by 46 publications

References 17 publications

Experimental and computational determination of Brønsted coefficients for equilibrium transfer of the O,O‐dimethyl phosphorothioyl group between oxyanion nucleophiles

Experimental and computational determination of Brønsted coefficients for equilibrium transfer of the O,O‐dimethyl phosphorothioyl group between oxyanion nucleophiles

Tryptophan-based fluorophores for studying protein conformational changes

From DNA to Nerve Agents – The Biomimetic Catalysts for the Hydrolysis of Phosphate Esters

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