Synthesis and electrochemical study of some novel alkynylferrocene derivatives

Abstract

Ferrocene and their derivatives are well-known redox active materials and were extensively used by construction of modified electrodes for the design of electrochemical sensors and biosensors. Substituent derivatization of ferrocene offers the prospect of controlling ferrocene moiety properties such as solubility, stability, reversibility of oxidation wave (important for their role as an electron transfer mediator) and oxidation potential, which is critical in the electrochemical determination of biological compounds. A new series of rigid alkynylferrocene including of 2-ferrocenylethynyl fluoren (3a), 2-ferrocenylethynyl fluoren-9-one (3b), 4-ferrocenylethynyl aniline (3c) and 3-ferrocenylethynyl-1-trifluoromethyl benzene (3d) have been prepared in good yields by Sonogashira coupling reaction. All products were characterized by 1 H and 13 C NMR, FT-IR, and elemental analysis. The redox chemistry of these compounds has been investigated by cyclic voltammetry. The half-wave potential of the terminal ferrocenyl moieties increases progressively in the order of 3c<3a<3b<3d, which is consistent with the electron density on the ferrocenyl unit.

Copper-free Sonogashira cross-coupling reactions: an overview

“…These catalysts have recently been reported to efficiently promote this type of Sonogashira reaction due to likely inhibition of dearomative rearrangement step in the catalytic cycle. Similar reports of copper and amine-free Sonogashira reaction have also been reported to catalyze the synthesis of pyrazolo [5,1b] [1,3]oxazoles in water as well as arylation of phenylacetylene [89][90][91] or functionalization of quinoline scaffolds 88 with or without using ligands, respectively. In 2016, Karami et al employed a heterogeneous organic-inorganic hybrid catalyst as an efficient tool in this reaction.…”

“…A considerable efficiency is afforded under ordinary conditions through this unique combination of reagents (Scheme 1). 2,3 The signicance of the present work lies in the issues that arise in the presence of Cu in the Sonogashira reaction, 4 some of which are environmentally friendly, 5,6 or solid-supported Pd catalysts. 7 For the rst time, this cross-coupling reaction was outlined by Kenkichi Sonogashira et al in 1975, then rapidly developed using various catalysts, additives, and ligands under different conditions.…”

Estudo matemático de estabilidade do desempenho do sistema [Fe(CN)6]3–/[Fe(CN)6]4– como mediador na eletrorredução de nitrito, com fins eletroanalíticos

“…omo se vê, apesar de o desempenho do mediador não depender do pH, como foi o caso do ferroceno [69,70], os prótons participam do processo de redução, ou seja, o desempenho do sensor de nitrito depende do pH. Por isso, para a descrição matemática do funcionamento do sensor, introduzir-se-ão as 3 variáveis: Ν -a concentração da substância que contém nitrito na camada pré-superficial; ϑ -o grau do recobrimento do cátodo pelo hexacianoferrato (III); h -a concentração de prótons na camada pré-superficial.…”