Application and Utilization of Electrochemistry in Organic Chemistry

Tomas      Navratil

Abstract

Many modern devices, which have surrounded people in daily life, are seen by their users as “black boxes”: they perform their task and only a few specialists understand the principles of their function. The students learn about electrochemistry, they know the terms as “battery”, “capacitor”, “electrode”, “a kitchen salt electrolysis”, “measurement of pH” etc. Some drivers know the principles of the car batteries. The same people gained (more or less deep) knowledge about organic chemistry during their studies. However, only a few of them are able to connect the utilization of electrochemistry with organic chemistry. Nevertheless, these two terms have been widely and intensively interconnected for many decades.

During its development, electrochemistry has become an integral part of many branches of natural science and it is practically impossible to define (similarly as in other scientific branches) the borders between electrochemistry and fields, in which have been its “results” utilized. Only shortly for illustration: Electrochemistry has been very often applied in investigation, characterization, purification, or synthesis of organic compounds. In medicine, many laboratory results are utilized without knowing that they were obtained by application of electrochemical methods. Brdicka's reaction has been utilized in medicine, and in biochemistry in investigation of proteins, peptides, phytochelatines, metallothioneins, etc., for almost 80 years (Brdicka, R. Polarographic studies with the dropping mercury cathode. Part XXXIII. A new test for proteins in the presence of cobalt salts in solutions of ammonium chloride. Collect. Czech. Chem. Commun., 1933, 5, 112-128.). Voltammetric methods can be utilized in studies of DNA, RNA, proteins, and processes connected with metabolism of carcinogenic, mutagenic, and toxic compounds. These methods help to reveal the metabolic pathways in human body. Very famous and intensively developed are sensors and biosensors, based on electrochemical principles. The combination of powerful separation techniques such as high performance chromatography and electromigration techniques with extremely sensitive and relatively selective electrochemical detection take place in almost any laboratory.

Frankly to say, it was a great challenge and commitment for me to be a guest editor of this special issue. When I started to take this task into consideration, I have had to answer some questions, e.g.: Which kind of electrochemistry would be interesting for organic chemists? How to extend their knowledge? How to attract their attention? Which information would be useful for them and for topics solved by them? There exist many possibilities how to solve such task. I consulted it with my colleagues and we decided to highlight the voltammetric techniques, to illustrate the modern trends of their applications, to judge critically the possibilities of their utilization in organic chemistry and to insinuate the further aims for cooperation among scientists of various branches.

In February 2012, we commemorate 90th anniversary of the invention of the polarography by the phenomenal Czech scientist Professor Jaroslav Heyrovsk (more precisely, the birthday is February 10th, 1922, in the afternoon, when the first polarographic curves were plotted) (Heyrovsky, J. Electrolysis with dropping mercury electrode (In Czech). Chem. Listy, 1922, 16, 256-264.). Thirty seven years later, on December 10th, 1959, at 4.30 p.m. in Stockholm, Sweden, he was awarded the Nobel Prize “for the polarographic method of analysis” from the hands of King Gustav Adolph VI. (Fig. (1), Fig (2)). Professor Heyrovsk was convinced that his method was mostly suitable for application in physical chemistry. However, already during his life polarography had been used in many other branches of human activities: analytical chemistry, inorganic chemistry, biochemistry, medicine, chemical physics, etc. Further development of this technique and introduction of the solid electrodes and electrodes containing no liquid mercury (such techniques are called voltammetry) have enabled expansion of electrochemistry generally (and voltammetry especially) into many other branches, organic chemistry including (Baizer, M. M. In Organic electrochemistry, Lund, H.; Baizer, M. M., Eds. Marcel Dekker 1991; p. 1421.) (Lund, H. A century of organic electrochemistry. J. Electrochem. Soc., 2002, 149(4), S21-S33.).....