A Versatile Electrochemical Batch Reactor for Synthetic Organic and Inorganic Transformations and Analytical Electrochemistry

Abstract

A standardized and versatile electrochemical batch reactor that has wide applicability in both organic and inorganic synthesis and analytical electrochemistry has been developed. A variety of synthetic electrochemical transformations have been performed to showcase the versatility and demonstrate the reactor, including the synthesis of five Cu(I)-NHC, two Au(I)-NHC and one Fe(II)-NHC complex, as well as an Fe(III)-salen complex. The reactor is based on a commercially available vial with an adapted lid, making it inexpensive and highly flexible. It features a fixed interelectrode distance which is crucial for reproducibility, along with the ability to accommodate a variety of interchangeable electrode materials. The reactor has also been used in conjunction with a parallel plate allowing rapid screening and optimization of an organic electrochemical transformation. Cyclic voltammetry has been performed within the reactor on a range of imidazolium salt analytes with the use of an external potentiostat. The ability to use this reactor for both analytical and synthetic organic and inorganic chemistry is enabled by a flexible and characterizable design.

Electrochemical Generation of N‐Heterocyclic Carbenes for Use in Synthesis and Catalysis

“…Current developments in the field of synthetic electrochemistry will allow more chemists access to electrochemical methods. As such, tutorials [1 ° ,1p] and the advancement of new, user‐friendly equipment [2d,53] will catalyze the adoption of electrochemistry as an everyday method in the synthetic laboratory.…”

“… Selected examples of metal‐NHC complexes synthesized electrochemically by A : Chen and co‐workers; [38] B : Willans and co‐workers; [2d,39] C : Abbehausen and co‐workers [40] …”

“…Our group has added a valuable extension to this methodology using ligands that are void of pendant donor arms and that form both cationic bis‐NHC complexes and neutral mono‐NHC complexes of Cu(I), Au(I) and Fe(II), including ligands bearing base sensitive N ‐substituents (Figure 2B), and Cu(II), Zn(II), Fe(II), Fe(III), Mn(II) and Mn(IV) salen‐complexes [2d,39] …”

Imidazolium-Based N-Heterocyclic Carbenes (NHCs) and Metal-Mediated Catalysis

“…Therefore, based on the electrochemical method, it is possible to choose appropriate NHC precursors [43]. A number of electrochemical studies related to the NHC metal complexes were also reported [44][45][46][47][48], the data of few selective NHC precursors (i.e., azolium salts) and its corresponding reduction potential are summarized from the literature (Table 2).…”

On-Demand Electrochemical Synthesis of Tetrakisacetonitrile Copper(I) Triflate and Its Application in the Aerobic Oxidation of Alcohols

“…To determine if 2.2 F mol −1 is necessary in the electrolysis step to achieve full conversion to benzaldehyde in the catalytic step, the electrolysis was performed as above with aliquots taken at time intervals corresponding to a range of 1.0−2.3 F mol −1 (Figure 1). 48 The catalytic step requires a basic reaction medium, and any residual triflic acid from the electrolysis step may neutralize the N-methylimidazole present in the catalytic step. The sensitivity of the catalytic reaction was probed by spiking the reaction mixture with triflic acid, and the efficiency of the reaction was found to be highly susceptible to the presence of triflic acid (Table S2).…”