Model Systems for Flavoenzyme Activity. Molecular Recognition of Flavin at the Polymer-Liquid Interface

The redox potential of flavin derivatives as a mediator in biosensors

The two-electron reduction potential for a set of 393 flavin derivatives is presented in this article. These derivatives are substituted flavin on carbon 6, 7, 8, and 9 by coinage transition metals (Cu, Ag, and Au) and conjugated double bond hydrocarbons; and both groups are examined with and without functional groups such as OH, Cl, CH₃, COOH, and NO₂. In order to show the validity of the results, the reduction potential of human life molecules, which have experimental values, such as flavin adenine dinucleotide (FAD) and riboflavin (vitamin B₂) is calculated. The experimental value for FAD is - 0.22 V, while the obtained theoretical value is - 0.21 V, and the corresponding values for riboflavin are - 0.18 and - 0.19 V, respectively. Theoretical calculations have been carried out by DFT procedure with a 6-31+G** basis set and BLYP xc-functional for coinage transition metals substitution, and MPW1PW9 xc-functionals for conjugated double bond hydrocarbon substitution. Both xc-functionals are chosen by the DFT calibration procedure.

Exploring the Mechnisms of Molecular Recognition by Flavins

The design and development of chemical models for enzymes depends on the fundamental principles observed in biological systems. Molecular recognition of flavins by various receptors has attracted attention due to their applications as chemical models for flavoenzymes. The area of molecular recognition is being investigated through research at the interface of chemistry and biology. In this review, the literature has been surveyed to provide comprehensive coverage of the synthetic methodology of different flavins and receptors and their molecular-recognition studies. Various applications of flavin-receptor complexes have also been highlighted.

Direct conversion of aldehydes to amides, tetrazoles, and triazines in aqueous media by one-pot tandem reactions

A variety of aldehydes reacted with iodine in ammonia water at room temperature to give the nitrile intermediates, which were trapped by addition of hydrogen peroxide, sodium azide, or dicyandiamide to produce their corresponding amides, tetrazoles, and 1,3,5-triazines in modest to high yields. The one-pot tandem reactions were conducted in water media, and the products were obtained simply by extraction or filtration.