A green method on the electro-organic synthesis of new caffeic acid derivatives: Electrochemical properties and LC–ESI–MS analysis of products

Versatile Tools for Understanding Electrosynthetic Mechanisms

Electrosynthesis is a popular, green alternative to traditional organic methods. Understanding the mechanisms is not trivial yet is necessary to optimize reaction processes. To this end, a multitude of analytical tools is available to identify and quantitate reaction products and intermediates. The first portion of this review serves as a guide that underscores electrosynthesis fundamentals, including instrumentation, electrode selection, impacts of electrolyte and solvent, cell configuration, and methods of electrosynthesis. Next, the broad base of analytical techniques that aid in mechanism elucidation are covered in detail. These methods are divided into electrochemical, spectroscopic, chromatographic, microscopic, and computational. Technique selection is dependent on predicted reaction pathways and electrogenerated intermediates. Often, a combination of techniques must be utilized to ensure accuracy of the proposed model. To conclude, future prospects that aim to enhance the field are discussed.

Preparation of MIP-based QCM nanosensor for detection of caffeic acid

In the present work, a new caffeic acid imprinted quartz crystal microbalance (QCM) nanosensor has been designed for selective assignation of caffeic acid in plant materials. Methacrylamidoantipyrine-iron(III) [MAAP-Fe(III)] as metal-chelating monomer has been used to prepare selective molecular imprinted polymer (MIP). MIP film for detection of caffeic acid has been developed on QCM electrode and selectivity experiments and analytical performance of caffeic acid imprinted QCM nanosensor has been studied. The caffeic acid imprinted QCM nanosensor has been characterized by AFM. After the characterization studies, imprinted and non-imprinted nanosensors was connected to QCM system for studies of connection of the target molecule, selectivity and the detection of amount of target molecule in real samples. The detection limit was found to be 7.8 nM. The value of Langmuir constant (b) (4.06 × 10(6)) that was acquired using Langmuir graph demonstrated that the affinity of binding sites was strong. Also, selectivity of prepared caffeic acid imprinted nanosensor was found as being high compared to chlorogenic acid. Finally, the caffeic acid levels in plant materials was determined by the prepared QCM nanosensor.

Molecular geometry, vibrations and electrode potentials of 2-(4,5-dihydroxy-2-methylphenyl)-2-phenyl-2H-indene-1,3-dione; experimental and theoretical attempts

The electrode potential of 2-(4,5-dihydroxy-2-methylphenyl)-2-phenyl-2H-indene-1,3-dione (DMPID) in acetonitrile has been calculated. The calculations were performed using ab initio molecular orbital calculations (HF), and density functional theory (DFT) with the inclusion of entropic and thermochemical corrections to yield free energies of redox reactions. The electrode potential of DMPID was also obtained experimentally with the aid of an electrochemical technique (cyclic voltammetry). The values for geometric parameters and the vibrational frequencies of DMPID and 2-(6-methyl-3,4-dioxocyclohexa-1,5-dienyl)-2-phenyl-2H-indene-1,3-dione (MDPID) were also computed using the same levels with the basis set of 6-31G(d). The calculated IR spectrum of DMPID used for the assignment of IR frequencies was observed in the experimental FT-IR spectrum and the calculated IR and FT-IR observed spectra of DMPID were compared with correlation factor of 0.996. It should be mentioned that the present work is the first research on coagulant derivative molecules in which the electrode potential of a molecule is calculated. Optimized structures of 2-(6-methyl-3,4-dioxocyclohexa-1,5-dienyl)-2-phenyl-2H-indene-1,3-dione (MDPID).

Electrochemical behavior of caffeic acid at single-walled carbon nanotube:graphite-based electrode

The performance of a single-walled carbon nanotube:graphite-based electrode, prepared by mixing single-walled carbon nanotubes (SWCNTs) and graphite powder, is described. The resulting electrode shows an excellent behavior for the redox of caffeic acid (CA), an important biological molecule. Due to the existing resemblance between electrochemical and biological reactions, it can be assumed that the oxidation mechanisms on the electrode and in the body share similar principles. SWCNT:graphite-based electrode presents a significant decrease in the overvoltage for the CA oxidation as well as a dramatic improvement in the reversibility of the CA redox behavior in comparison with the graphite-based and glassy carbon (GC) electrodes.