CuII Complexes Research Articles

The Effect of Intramolecular Proton Transfer on the Mechanism of NO Reduction to N2O by a Copper Complex: A DFT Study.

DFT calculations were performed to explore the mechanism underlying the reduction of NO to N2O by a CuI complex. A nitrosyl complex reacts with another NO molecule and the CuI complex, leading to the formation of a dicopper-hyponitrite complex (Cu2N2O2). The first steps follow a common pathway until the formation of the intermediate [CuII-N2O2]+, after which the reaction pathway diverges into three Cu2N2O2 species: κ2-N,N', κ2-O,O', and κ3-N,O,O'. These species yield different products along their respective reaction pathways. In the case of the κ2-N,N' and κ3-N,O,O' species, the subsequent steps involve a methanol-mediated proton transfer and N-O bond cleavage, resulting in the generation of N2O and [CuII-OH]+. Conversely, for the κ2-O,O' species, two proton transfers occur without N-O bond cleavage, leading to the formation of H2N2O2 and [CuII]2+. H2N2O2 spontaneously converts into N2O and H2O. These computational results elucidate how the coordination mode of hyponitrite influences reactivity and provide insights into NO reduction via proton transfer. Notably, switching of the N2O2 coordination mode to metal ions from N to O was not required, offering insights for more efficient NO reduction strategies in the future.

Copper(II) Complexes of Phenolate‐Bridged Dimeric Cyclam Ligands: Synthesis, Coordination and Electrochemical Study

AbstractBis(macrocyclic) complexes are investigated as artificial analogues of natural dinuclear metalloenzymes. Two ligands containing two cyclam rings connected through a p‐cresol or 4‐nitrophenol spacer were synthesized and their complexing properties were investigated. CuII complexes were prepared and their properties were studied by a combination of spectral, diffraction and electrochemical methods. The phenolate group is not or only weakly coordinated to the central CuII ion and the two macrocycles behave mostly as two independent complexing units. All the determined solid‐state structures showed cyclam adopting trans‐III geometry, however, solution study indicated the presence of more isomers in the solution whose abundance changes with pH. Electrochemical reduction of the complexes is irreversible and results in the reductive decomplexation to amalgamated Cu metal. The amalgamated metal is re‐oxidized to CuII during the anodic scan of CV and the metal ion is re‐coordinated. The ligand containing the nitro group shows an irreversible four‐electron reduction of the nitro group. The ligands and the complexes undergo also a slow degradation when incubated in the aqueous solutions for a prolonged time. The degradation relies on the “retro‐Mannich” cleavage of the methylene bridge connecting the cyclam ring with the phenol moiety.

Electrometric Study on Nature and Stability of CoII, NiII and CuII Complexes with 5-Sulfosalicylic Acid in DMSO-Water Mixtures

Electrometric Study on Nature and Stability of CoII, NiII and CuII Complexes with 5-Sulfosalicylic Acid in DMSO-Water Mixtures

Tuning of the Electronic Structure and Reactivity of Metal Complexes with Redox‐Active Guanidine Ligands

Redox‐active ligands change more drastically the electronic structure of metal complexes than non‐redox‐active ligands, with consequences on the magnetic and optical properties as well as the (redox) reactivity. In this work, redox‐active guanidine ligands are integrated in cobalt and copper complexes. The variations in the electronic structures of cobalt complexes, in particular the relative energies of the states corresponding to high spin CoII or low‐spin CoIII, in dependence of the redox‐active o‐diguanidine ligand manifest itself in different magnetic properties. Moreover, the electron transfer rates for copper complexes with two redox‐active diguanidino‐benzene ligands (self‐exchange betweeen a monocationic CuI complex and the corresponding dicationic complex) were varied systematically over two orders of magnitude by choice of the redox‐active diguanidine ligand, realizing redox pairs with intermediate or record‐high rates.

Synthesis, Characterization, and Biological Evaluation of Novel [M(η6-arene)2]+ (M = Re, 99mTc) Hosted Terpyridines and Copper Complexes Thereof.

We report the synthesis, characterization, and in vitro biological activities of [Re(η6-arene)2]+-terpyridine conjugates and their CuII complexes. The terpyridine (terpy) chelators were attached to the [Re(η6-arene)2]+ scaffold via secondary amine linkers allowing for heteroleptic mono- and homoleptic bis-terpyridine-substituted chelators. Complexation with CuCl2 afforded the respective square pyramidal [Cu(terpy)Cl2] complexes hosted on the [Re(η6-arene)2]+ scaffold. The chelator conjugates and their respective complexes were found to be remarkably cytotoxic against malignant HT29 and A549 human cancer cell lines in vitro with IC50 values in the low micromolar range. Mitochondrial respiration disruption was identified as a possible mode of action of these novel drug candidates. Crucially, the [Re(η6-arene)2]+ hosts delivered water solubility of the otherwise insoluble [Cu(terpy)Cl2] motif. Importantly, the homoleptic [99mTc(η6-arene)2]+-terpyridine conjugate is available in a single step, which enables the presented system to be used as a theranostic approach to modern medicinal inorganic chemistry.

A Bioinspired Nonheme FeIII-(O22-)-CuII Complex with an St = 1 Ground State.

Cytochrome c oxidase (CcO) is a heme copper oxidase (HCO) that catalyzes the natural reduction of oxygen to water. A profound understanding of some of the elementary steps leading to the intricate 4e-/4H+ reduction of O2 is presently lacking. A total spin St = 1 FeIII-(O22-)-CuII (IP) intermediate is proposed to reduce the overpotentials associated with the reductive O-O bond rupture by allowing electron transfer from a tyrosine moiety without the necessity of any spin-surface crossing. Direct evidence of the involvement of IP in the CcO catalytic cycle is, however, missing. A number of heme copper peroxido complexes have been prepared as synthetic models of IP, but all of them possess the catalytically nonrelevant St = 0 ground state resulting from antiferromagnetic coupling between the S = 1/2 FeIII and CuII centers. In a complete nonheme approach, we now report the spectroscopic characterization and reactivity of the FeIII-(O22-)-CuII intermediates 1 and 2, which differ only by a single -CH3 versus -H substituent on the central amine of the tridentate ligands binding to copper. Complex 1 with an end-on peroxido core and ferromagnetically (St = 1) coupled FeIII and CuII centers performs H-bonding-mediated O-O bond cleavage in the presence of phenol to generate oxoiron(IV) and exchange-coupled copper(II) and PhO• moieties. In contrast, the μ-η2:η1 peroxido complex 2, with a St = 0 ground state, is unreactive toward phenol. Thus, the implications for spin topology contributions to O-O bond cleavage, as proposed for the heme FeIII-(O22-)-CuII intermediate in CcO, can be extended to nonheme chemistry.

A Strongly Ambiphilic Ferrocene-Based Cyclic (Alkyl)(amino)carbene - Specific Decomposition to an Enamine by a 1,2-Phenyl Shift.

The recently described crystalline cyclic (alkyl)(amino)carbene with a 1,1'-ferrocenylene (fc) backbone fc(CPh2-C-NMes) (A, Mes = mesityl) is highly reactive due to its particularly pronounced ambiphilicity and is thermally not stable in solution due to an intramolecular insertion of the divalent carbon atom into a methyl C-H bond of the Mes substituent. The closely related congener fc(CPh2-C-N-p-C6H4-tBu) (1) cannot undergo such an insertion reaction. Nevertheless, 1 is too short-lived for isolation due to a rapid 1,2-shift of a phenyl group, furnishing the isomeric cyclic enamine fc[C(Ph)=C(Ph)-N-p-C6H4-tBu] (1') in a specific decomposition process unprecedented for CAACs. Trapping of 1 was possible with carbon monoxide, elemental selenium and with [CuBr(SMe2)], respectively affording the aminoketene 1=C=O, the selenoamide 1=Se and the homoleptic CuI complex [Cu(1)2][CuBr2]. 1 is an even stronger ambiphile than A according to NMR spectroscopic data. Similar to A, 1 does not react with H2, because the experimentally observed intramolecular process is kinetically more favourable according to DFT results.

Synthesis, crystal structure and Hirshfeld surface analysis of [Cu(H2 L)2(μ-Cl)CuCl3]·H2O [H2 L = 2-hy-droxy-N'-(propan-2-yl-idene)benzohydrazide

The present study focuses on the synthesis and structural characterization of a novel dinuclear CuII complex, [tri-chlorido-copper(II)]-μ-chlorido-{bis-[2-hy-droxy-N'-(propan-2-yl-idene)benzohydrazide]copper(II)} monohydrate, [Cu2Cl4(C10H12N2O2)2]·H2O or [Cu(H2 L)2(μ-Cl)CuCl3]·H2O [H2 L = 2-hy-droxy-N'-(propan-2-yl-idene)benzohydrazide]. The complex crystallizes in the monoclinic space group P21/n with one mol-ecule of water, which forms inter-actions with the ligands. The first copper ion is penta-coordinated to two benzohydrazine-derived ligands via two nitro-gen and two oxygen atoms, and one bridging chloride, which is also coordinated by the second copper ion alongside three terminal chlorines in a distorted tetra-hedral geometry. The arrangement around the first copper ion exhibits a distorted geometry inter-mediate between trigonal bipyramidal and square pyramidal. In the crystal, chains are formed via inter-molecular inter-actions along the a-axis direction, with subsequent layers constructed through hydrogen-bonding inter-actions parallel to the ac plane, and through slipped π-π stacking inter-actions parallel to the ab plane, resulting in a three-dimensional network. The inter-molecular inter-actions in the crystal structure were qu-anti-fied and analysed using Hirshfeld surface analysis. Residual electron density from disordered methanol mol-ecules in the void space could not be reasonably modelled, thus a solvent mask was applied.

A luminescent Cu2I2P2S2-type binuclear complex and its fluorescence sensing for pyridine.

Luminescent CuI complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title Cu2I2P2S2-type binuclear complex, di-μ-iodido-bis[(thiourea-κS)(triphenylphosphine-κP)copper(I)], [Cu2I2(CH4N2S)2(C18H15P)2], conventionally abbreviated as Cu2I2TPP2TU2, where TPP and TU represent triphenylphosphine and thiourea, respectively, is described. In this complex, each CuI atom adopts a CuI2PS four-coordination mode and pairs of atoms are connected to each other by two μ2-I ligands to form a centrosymmetric binuclear cluster. It was also found that the paper-based film of this complex exhibited obvious luminescence light-up sensing for pyridine and 4-methylpyridine.

Poly[tris-(2-amino-butan-1-ol)copper(II) [hexa-kis-μ2-cyanido-κ12 C:N-tetra-copper(I)] bis-(2-amino-butan-1-olato)aqua-copper(II) monohydrate

The title structure, {[Cu(C4H11NO)3][Cu4(CN)6]·[Cu(C4H10NO)2(H2O)]·H2O} n , is made up of diperiodic honeycomb CuICN networks built from [Cu4(CN)6]2- units, together with two independent CuII complexes: six-coord-inate [Cu(CH3CH2CH(NH2)CH2OH)3]2+ cations, and five-coordinate [Cu(CH3CH2CH(NH2)CH2O)2·H2O] neutral species. The two CuII complexes are not covalently bonded to the CuICN networks. Strong O-H⋯O hydrogen bonds link the CuII complexes into pairs and the pairs are hydrogen bonded into chains along the crystallographic b axis via the hydrate water mol-ecule. In addition, O-H⋯(CN) and N-H⋯(CN) hydrogen bonds link the cations to the CuCN network. In the honeycomb polymeric moiety, all bridging cyanido ligands are disordered over two orientations, head-to-tail and tail-to-head, with occupancies for C and N atoms varying for each CN group.

Direct Enantiomer Differentiation of Drugs and Drug-Like Compounds via Noncovalent Copper-Amino Acid Complexation and Ion Mobility-Mass Spectrometry.

Drug enantiomers can possess vastly different pharmacological properties, yet they are identical in their chemical composition and structural connectivity. Thus, resolving enantiomers poses a great challenge in the field of separation science. Enantiomer separations necessitate interaction of the analyte with a chiral environment─in mass spectrometry-based analysis, a common approach is through a three-point interaction with a chiral selector commonly introduced during sample preparation. In select cases, the structural difference imparted through noncovalent complexation results in enantiomer-specific structural differences, facilitating measurement using a structurally selective analytical technique such as ion mobility-mass spectrometry (IM-MS). In this work, we investigate the direct IM-MS differentiation of chiral drug compounds using mononuclear copper complexes incorporating an amino acid chiral selector. A panel of 20 chiral drugs and drug-like compounds were investigated for separation, and four l-amino acids (l-histidine, l-tryptophan, l-proline, and l-tyrosine) were evaluated as chiral selectors (CS) to provide the chiral environment necessary for differentiation. Enantiomer differentiation was achieved for four chiral molecule pairs (R/S-thalidomide, R/S-baclofen, R/S-metoprolol, and d/l-panthenol) with two-peak resolution (Rp-p) values ranging from 0.7 (>10% valley) to 1.5 (baseline separation). Calibration curves relating IM peak areas to enantiomeric concentrations enabled enantiomeric excess quantitation of racemic thalidomide and metoprolol with residuals of 5.7 and 2.5%, respectively. Theoretical models suggest that CuII and l-histidine complexation around the analyte chiral center is important for gas-phase stereoselectivity. This study demonstrates the potential of combining enantioselective noncovalent copper complexation with structurally selective IM-MS for differentiating chiral drugs and drug-like compounds.

Electrochemically Active Copper Complexes with Pyridine-Alkoxide Ligands

Pyridine-alkoxide (pyalk) ligands that support transition metals have been studied for their use in electrocatalytic applications. Herein, we used the pyalk proligands diphenyl(pyridin-2-yl)methanol ([H]PhPyalk, L1), 1-(pyren-1-yl)-1-(pyridin-2-yl)ethan-1-ol ([H]PyrPyalk, L2), 1-(pyridine-2-yl)-1-(thiophen-2-yl)ethan-1-ol ([H]ThioPyalk, L3), and 1-(ferrocenyl)-1-(pyridin-2-yl)ethan-1-ol ([H]FePyalk, L4) to synthesize CuII complexes that vary in nuclearity and secondary coordination sphere. Also, the proligand 1-(ferrocenyl)-1-(5-methoxy-pyridin-2-yl)ethan-1-ol ([H]FeOMePyalk, L5) was synthesized with a methoxy substituted pyridine; however, the isolation of a CuII complex ligated by L5 was not possible. Under variable reaction conditions, the pyalk ligands reacted with CuII precursors and formed either mononuclear or dinuclear CuII complexes depending on the amount of ligand added. The resulting complexes were characterized by single crystal X-ray diffraction, elemental analysis, and cyclic voltammetry.

Design, synthesis, structural characterization, molecular docking, antibacterial, anticancer activities, and density functional theory calculations of novel MnII, CoII, NiII, and CuII complexes based on pyrazolone-sulfadiazine azo-dye ligand

This study was designed to prepare novel metal chelates obtained from 4-((3-methyl-5-oxo-1-phenyl-pyrazol-4-yl)diazenyl)-N-(pyrimidin-2-yl) benzenesulfon amide (MPSA). They are characterized through CHN-analysis, spectroscopic (1HNMR, FT-IR, UV–Vis), mass, and TG analysis. The FT-IR and UV–visible spectra were related to the computed results and showed good conformity. The mass spectra determined that the ligand's molecular weight and chelates matched well with the found m/z values. The optimization for the studied chelates indicated the formation of distorted octahedral geometry for the prepared chelates. The B3LYP/6–311G** level for the free ligand and the B3LYP/6–311G**-LANL2DZ functional level for the metal ions in chelates were used in density functional theory (DFT) calculations. The results showed that the DFT computations match those of the experimental ones. Using the B3LYP/6–31G(d,p) basis set, TD-DFT/PCM was applied to determine the electronic spectral transitions of the produced compounds. Also, B3LYP/6–31G(d,p) has been utilized to implement the vibrational wavenumbers, and the results are reliable with the innovative ones. The antimicrobial activities of the compounds were experimentally established against a subsection of G+ and G- bacteria. The anticancer activities of the ligand were examined against some cell lines. The MCF7 cell line had the highest activity and was subjected to the anticancer effect of the ligand and its chelates. The cytotoxicity on normal cells was estimated against normal HSF cell lines. The outcomes demonstrated that chelates enhanced their cytotoxic and anticancer properties. Molecular docking mechanisms were done to establish how the obtained substances attach to the breast cancer-targeted protein binding sites,

Tandem Mass Spectrometry Approaches for Differentiation and Quantification Pidotimod and Its Three Isomers in the Gas Phase.

Pidotimod is a chiral drug that possesses two chiral centers, resulting in three isomeric impurities (analytes, A). This study employs electrospray ionization ion trap mass spectrometry (ESI-MS) through collision-induced dissociation (CID) to investigate the chiral recognition of pidotimod and its three isomers to eliminate chromatographic separation. Three approaches were explored: (1) Protonated molecules in CID exhibited discriminative potential for diastereomers, with the ability to distinguish between S,S and R,R configurations, albeit with an Rchiral value of ~1.8. However, differentiation between R,S and S,R configurations was not achievable. (2) Alkali adductions (lithium and sodium) only discerned diastereomers. The Rchiral values of the diastereomers obtained from alkali adduct ions were significantly lower than those obtained from protonated ions. (3) Therefore, a third approach was used to address the challenge of distinguishing between R,S and S,R configurations, including the introduction of chiral references (ref) and transition metals (MII) to form metal-bound complexes [MII(A)(ref)-H]+. Additionally, we synthesized a novel ligand, 4-(N-tert-butoxycarbonyl [Boc]-L-prolinamido)phenol (denoted as ligand A), by modifying N-t-Boc-L-Pro with 2-aminophenol, which, in combination with CuII and NiII, enabled simultaneous differentiation of all four isomers. CuII complexes exhibited significant chiral selectivity between R,S and S,R configurations. Density functional theory calculations were performed to further elucidate the stereodynamic behavior and stoichiometry of these ions in the gas phase. These calculations revealed the interaction energy and coordination sites of the precursor ions in the gas phase, correlating well with MS/MS experiment results. Additionally, the logarithm of the CuII complexes' characteristic fragment ion abundance ratio demonstrated a strong linear relationship with enantiomeric excess (ee). This study presents a novel strategy for chiral drug quality control that eliminates chromatographic separation.

Synthesis and Aerobic Oxidation of Perfluoroalkyl d10 Metal Complexes Supported by 2,7‐Dimethyl‐1,8‐Naphthyridine

AbstractThe coordination chemistry of 2,7‐dimethyl‐1,8‐naphthyridine has been explored with perfluoroalkyl d10 metals, CuI, ZnII, and AgI. This ligand was shown to form dicoordinate CuI and AgI mono‐perfluoroalkyl complexes where naphthyridine coordinates with only one N‐donor, while bidentate coordination with both N‐atoms was observed in Zn bis(perfluoroalkyl) complexes forming a strained four‐membered chelate ring. Copper complexes undergo facile oxidation in the presence of air or excess O2 to give tetracoordinate CuII complexes coordinated to perfluorocarboxylates formed by oxygenation of the metal‐adjacent α‐CF2 position of the corresponding perfluoroalkyl ligands. Another type of product formed by the oxidation of perfluoroethylcopper(I) complexes in the presence of substoichiometric O2 are binuclear CuI⋅⋅⋅CuI complexes with two perfluorocarboxylate ligands. In the presence of an external substrate, alkene, O‐atom transfer was observed to give oxygenated products, resembling the recently reported O‐transfer reactivity of naphthyridine‐supported Ni long‐chain perfluoroalkyl complexes.

Twisted and Disconnected Chains: Flexible Linear Tetracuprous Arrays and a Decanuclear CuI Cluster as Blue- and Green/Yellow-Light Emitters.

Defined arrays of transition metal ions embedded in tailored polydentate ligand scaffolds allow for a systematic design of their physical properties. Such molecular strings of closed-shell transition metal centers are particularly interesting for Group 11 metal ions in the oxidation state +1 if they undergo metallophilic d10···d10 contact interactions since these clusters are oftentimes efficient photoluminescence (PL) emitters. Copper is particularly attractive as a sustainable earth-abundant coinage metal source and because of the ability of several CuI complexes to serve as powerful thermally activated delayed fluorescence (TADF) emitters in molecular/organic light-emitting devices (OLEDs). Our combined synthetic, crystallographic, photophysical, and computational study describes a straight tetracuprous array possessing a centrally disconnected CuI2···CuI2 chain and a continuous helically bent CuI4 complex. This molecular helix undergoes a facile rearrangement in diethyl ether solution, yielding an unprecedented nanosized CuI10 cluster (2.9 × 2.0 nm) upon crystallization. All three clusters show either bright blue phosphorescence, TADF, or green/yellow multiband phosphorescence with quantum yields between 6.5 and 67%, which is persistent under hydrostatic pressure up to 30 kbar. Temperature-dependent PL investigations in combination with time-dependent density-functional theory (TD-DFT) calculations and void space analyses of the crystal packings complement a comprehensive correlation between the molecular structures and photoluminescence properties.

22]Pentaphyrins(2.0.1.1.0) Displaying N-Fusion, Pyrrole-Rearrangement, and Dimerization Reactions Upon Oxidation and Metalation.

Exploration of expanded porphyrins with unprecedented reactivities has remained important. Here [22]pentaphyrins(2.0.1.1.0) were synthesized as a constitutional isomer of sapphyrin by acid-catalyzed cyclization of 1,14-dibromo-5,10-diaryltripyrrin with 1,2-di(pyrro-2-ly)ethenes. These pentaphyrins display roughly planar structures and varying aromaticities depending upon the vinylene structures. The 19,20-ditolyl pentaphyrin gave an N-fused product and an unprecedented pyrrole-rearranged product, depending upon the oxidation conditions. Remarkably, upon the metalation with CuCl, the N-fused product and the pyrrole-rearranged product afforded an inner β-β coupled face-to-face CuII complex dimer and an outer β-β coupled lateral CuII complex dimer, respectively, in fairly good yields. Further, [22]pentaphyrin(2.0.1.1.0) fused with a NiII porphyrin was effectively dimerized upon oxidation with MnO2 to give a 16-16' directly linked dl-dimer.

22]Pentaphyrins(2.0.1.1.0) Displaying N‐Fusion, Pyrrole‐Rearrangement, and Dimerization Reactions Upon Oxidation and Metalation

AbstractExploration of expanded porphyrins with unprecedented reactivities has remained important. Here [22]pentaphyrins(2.0.1.1.0) were synthesized as a constitutional isomer of sapphyrin by acid‐catalyzed cyclization of 1,14‐dibromo‐5,10‐diaryltripyrrin with 1,2‐di(pyrro‐2‐ly)ethenes. These pentaphyrins display roughly planar structures and varying aromaticities depending upon the vinylene structures. The 19,20‐ditolyl pentaphyrin gave an N‐fused product and an unprecedented pyrrole‐rearranged product, depending upon the oxidation conditions. Remarkably, upon the metalation with CuCl, the N‐fused product and the pyrrole‐rearranged product afforded an inner β‐β coupled face‐to‐face CuII complex dimer and an outer β‐β coupled lateral CuII complex dimer, respectively, in fairly good yields. Further, [22]pentaphyrin(2.0.1.1.0) fused with a NiII porphyrin was effectively dimerized upon oxidation with MnO2 to give a 16–16’ directly linked dl‐dimer.

Electrochemically Mediated Atom Transfer Radical Polymerization Driven by Alternating Current.

Alternating current (AC) and pulsed electrolysis are gaining traction in electro(organic) synthesis due to their advantageous characteristics. We employed AC electrolysis in electrochemically mediated Atom Transfer Radical Polymerization (eATRP) to facilitate the regeneration of the activator CuI complex on Cu0 electrodes. Additionally, Cu0 served as a slow supplemental activator and reducing agent (SARA ATRP), enabling the activation of alkyl halides and the regeneration of the CuI activator through a comproportionation reaction. We harnessed the distinct properties of Cu0 dual regeneration, both chemical and electrochemical, by employing sinusoidal, triangular, and square-wave AC electrolysis alongside some of the most active ATRP catalysts available. Compared to linear waveform (DC electrolysis) or SARA ATRP (without electrolysis), pulsed and AC electrolysis facilitated slightly faster and more controlled polymerizations of acrylates. The same AC electrolysis conditions could successfully polymerize eleven different monomers across different mediums, from water to bulk. Moreover, it proved effective across a spectrum of catalyst activity, from low-activity Cu/2,2-bipyridine to highly active Cu complexes with substituted tripodal amine ligands. Chain extension experiments confirmed the high chain-end fidelity of the produced polymers, yielding functional and high molecular-weight block copolymers. SEM analysis indicated the robustness of the Cu0 electrodes, sustaining at least 15 consecutive polymerizations.

Electrochemically Mediated Atom Transfer Radical Polymerization Driven by Alternating Current

AbstractAlternating current (AC) and pulsed electrolysis are gaining traction in electro(organic) synthesis due to their advantageous characteristics. We employed AC electrolysis in electrochemically mediated Atom Transfer Radical Polymerization (eATRP) to facilitate the regeneration of the activator CuI complex on Cu0 electrodes. Additionally, Cu0 served as a slow supplemental activator and reducing agent (SARA ATRP), enabling the activation of alkyl halides and the regeneration of the CuI activator through a comproportionation reaction. We harnessed the distinct properties of Cu0 dual regeneration, both chemical and electrochemical, by employing sinusoidal, triangular, and square‐wave AC electrolysis alongside some of the most active ATRP catalysts available. Compared to linear waveform (DC electrolysis) or SARA ATRP (without electrolysis), pulsed and AC electrolysis facilitated slightly faster and more controlled polymerizations of acrylates. The same AC electrolysis conditions could successfully polymerize eleven different monomers across different mediums, from water to bulk. Moreover, it proved effective across a spectrum of catalyst activity, from low‐activity Cu/2,2‐bipyridine to highly active Cu complexes with substituted tripodal amine ligands. Chain extension experiments confirmed the high chain‐end fidelity of the produced polymers, yielding functional and high molecular‐weight block copolymers. SEM analysis indicated the robustness of the Cu0 electrodes, sustaining at least 15 consecutive polymerizations.