Elusive pKa’ of aminoferrocene determined with voltammetric methods in buffered and unbuffered systems and practical aspects of such experiments

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F19%3A00107678" target="_blank" >RIV/00216224:14310/19:00107678 - isvavai.cz</a>

Result on the web

<a href="https://www.sciencedirect.com/science/article/pii/S0013468619310461" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0013468619310461</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.electacta.2019.05.113" target="_blank" >10.1016/j.electacta.2019.05.113</a>

Result language

angličtina

Original language name

Elusive pKa’ of aminoferrocene determined with voltammetric methods in buffered and unbuffered systems and practical aspects of such experiments

Original language description

Redox behaviour of aminoferrocene (FcNH2) in buffered and unbuffered systems has been studied. In unbuffered solutions with background electrolyte only, two discrete redox pairs of unprotonated and protonated forms were evident. On the other hand, in buffered systems only one redox centre was visible continuously shifting with pH. If one wants to determine the apparent acid dissociation constant pKa’ of ferrocene with protonatable side group, buffered environment will be the first choice. Throughout the electrochemical experiments at such conditions, the most limiting factor was the type of the electrode – gold, platinum, glassy carbon and boron-doped diamond electrodes were probed. We found that the influence of the surface of the electrode was so significant that either the determination of pKa’ was not possible at aqueous conditions or observed differences among the determined values were up to five units. In that case, elusive constants were determined. On the other hand, titrations performed in unbuffered systems appeared to be useable despite inconsistences and deficiencies that can be expected. Determined pKa's agreed well with that quantified using spectrophotometry. Although, experimental work at unbuffered conditions can be considered as incorrect or misleading at the first sight, interesting facts and unexpected mechanisms can be revealed. Especially, when one is aware of the possible risks, and the measurement in different (even unbuffered) media and with different tools are done simultaneously. Finally, a method for estimation of pKa’ of unstable compounds without their separation and isolation was introduced.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10403 - Physical chemistry

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach

Publication year

2019

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Electrochimica Acta

ISSN

0013-4686

e-ISSN

—

Volume of the periodical

318

Issue of the periodical within the volume

SEP

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

8

Pages from-to

534-541

UT code for WoS article

000478969600057

EID of the result in the Scopus database

2-s2.0-85067667920