Electrocarboxylation of arylmethyl chlorides catalyzed by cobalt 6,6′-bis(2-hydroxyphenyl)-2,2′-bipyridine

Renewable Electricity Enables Green Routes to Fine Chemicals and Pharmaceuticals

Syntheses of chemicals using renewable electricity and when generating high atom economies are considered green and sustainable processes. In the present state of affairs, electrochemical manufacturing of fine chemicals and pharmaceuticals is not as common place as it could be and therefore, merits more attention. There is also a need to turn attention toward the electrochemical synthesis of valuable chemicals from recyclable greenhouse gases that can accelerate the process of circular economy. CO₂ emissions are the major contributor to human-induced global warming. CO₂ conversion into chemicals is a valuable application of its utilisation and will contribute to circular economy while maintaining environmental sustainability. Herein, we present an overview of electro-carboxylation, including mechanistic aspects, which forms carboxylic acids using molecular carbon dioxide. We also discuss atom economies of electrochemical fluorination, methoxylation and amide formation reactions.

CO2 activation by electrogenerated divalent samarium for aryl halide carboxylation

The first combination of samarium and electrochemistry towards the effective reduction of CO₂ for the synthesis of benzoic acids from aryl halides.

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

The near-unlimited availability of CO₂ has stimulated a growing research effort in creating value-added products from this greenhouse gas. This paper presents the trends on the most important methods used in the electrochemical synthesis of carboxylic acids from carbon dioxide. An overview is given of different substrate groups which form carboxylic acids upon CO₂ fixation, including mechanistic considerations. While most work focuses on the electrocarboxylation of substrates with sacrificial anodes, this review considers the possibilities and challenges of implementing other synthetic methodologies. In view of potential industrial application, the choice of reactor setup, electrode type and reaction pathway has a large influence on the sustainability and efficiency of the process.

Programmed multiple complexation for the creation of helical structures from acyclic phenol-bipyridine oligomer ligands

Two new multidentate ligands, H3L(1) and H4L(2), possessing bipyridine-phenol repetitive units were designed so that the multi-metal complexation could produce a single-helical structure in a pre-programmed fashion. The ligands were synthesized by successive palladium-catalyzed coupling reactions. The complexation of H3L(1) with zinc(II) and nickel(II) acetate afforded [L(1)Zn2(OAc)] and [(L(1))2Ni4](OAc)2, respectively. Each of the ligand moieties in these complexes formed a one-turn single helix. The zinc(II) complex [L(1)Zn2(OAc)] underwent a helix compression-extension motion in solution. The complexation of the H3L(1) ligand with iron(III) chloride gave a dinuclear complex [(HL(1))2Fe2Cl2] with a non-helical dimeric structure. The longer ligand H4L(2) afforded a trinuclear complex [L(2)Zn3(OAc)2] with a 1.5-turn single-helical structure upon complexation with zinc(II) acetate. The reaction of the H4L(2) ligand with cobalt(II) acetate under aerobic conditions gave a mixed valence complex [L(2)Co3(OAc)3(OMe)], which had two trivalent and one divalent cobalt ions. The structural features of the trinuclear complexes significantly depended on the metals; [L(2)Co3(OAc)3(OMe)] had a helical pitch of 7.6 Å, which was almost twice that of [L(2)Zn3(OAc)2] (4.0 Å).