Charge-transfer Complexes Research Articles

Origin of the intermolecular forces that produce donor-acceptor stacks in π-conjugated charge-transfer complexes.

The attraction between π-conjugated planar electron donor and acceptor molecules that form many stable charge-transfer (CT) complexes has been explained by quantum chemical CT interactions, although the fundamental origin remains unclear. Here, we demonstrate the mechanism of CT complex formation by potential energy map analysis for TTF-CA and BTBT-TCNQ, using energy decomposition of intermolecular interaction by symmetry-adapted perturbation theory (SAPT) combined with coupled cluster calculation. We find that the source of attraction between donor and acceptor molecules is ascribed primarily to the dispersion force and also to the electrostatic force. In contrast, the contribution of CT interactions to the attractive forces is minimal. We demonstrate that the highly directional feature of the exchange repulsion force, coupled with the attractive dispersion and electrostatic forces, is crucial in determining the intermolecular arrangements of actual CT crystals. These findings are key for understanding the unique structural and electronic properties of π-conjugated CT complexes.

Enabling Visible Light Sensitization of YbIII, NdIII and ErIII in Dimeric LnIII/GaIII Metallacrowns through Functionalization with RuII Complexes for NIR‐II Multiplex Imaging

AbstractMultiplex imaging in the second near‐infrared window (NIR‐II, 1000–1700 nm) provides exciting opportunities for more precise understanding of biological processes and more accurate diagnosis of diseases by enabling real‐time acquisition of images with improved contrast and spatial resolution in deeper tissues. Today, the number of imaging agents suitable for this modality remains very scarce. In this work, we have synthesized and fully characterized, including theoretical calculations, a series of dimeric LnIII/GaIII metallacrowns bearing RuII polypyridyl complexes, LnRu‐3 (Ln=YIII, YbIII, NdIII, ErIII). Relaxed structures of YRu‐3 in the ground and the excited electronic states have been calculated using dispersion‐corrected density functional theory methods. Detailed photophysical studies of LnRu‐3 have demonstrated that characteristic emission signals of YbIII, NdIII and ErIII in the NIR‐II range can be sensitized upon excitation in the visible range through RuII‐centered metal‐to‐ligand charge transfer (MLCT) states. We have also showed that these NIR‐II signals are unambiguously detected in an imaging experiment using capillaries and biological tissue‐mimicking phantoms. This work opens unprecedented perspectives for NIR‐II multiplex imaging using LnIII‐based molecular compounds.

Optical and surface properties of Schiff base ligands and Cu(II) and Co(II) complexes

Objectives. To study the transition of electrons in 1,2-phenyl(4’-carboxy)benzylidene Schiff base ligand and transition metal ions, optical properties, as well as the surface chemistry of supported transition metals using diffuse reflectance spectroscopy (DRS); to study the roughness and morphology of the Schiff base ligand and its complexes using atomic force microscopy (AFM).Methods. DRS, AFM, and Fourier-transform infrared spectroscopy instruments were used to identify electron transitions, optical properties, and surface morphology in Schiff base ligands and their complexes.Results. The DRS revealed the d–d transitions and charge transfer shifts of all compounds, and helped identify the structure of the ligand. One of the optical properties studied was the energy gap calculation of the ligand and its complexes. The copper complex exhibited more semiconducting behavior with surface morphology properties such as surface roughness parameters lower than those of the ligand and the cobalt complex. This can be attributed to the smaller size of the copper atom, as well as lower electron transitions compared to the cobalt complex and the square planar bonding shape.Conclusions. In Schiff base ligands, the reflectance spectrum bands reveal three electron transitions: n→π*, π→π*, and σ→σ* transitions. In cobalt complexes, four transitions are indicated: 4A2(F)→4T1(F), 4A2(F)→4T1(P), charge transfer bands, and tetrahedral geometry. Copper complexes exhibit three transitions: 2B1g→2A1g, 2B1g→2Eg, and charge transfer bands, with a square planar geometry for their structure. The energy gap calculations were 2.42, 2.29, and 2.30 eV, respectively. In the case of the SH ligands, copper complexes, and cobalt complexes, all compounds exhibited semiconductor properties. However, the complexes displayed increased conductivity due to the influence of the metal and coordination structure.

An Increase in the Rigidity of the Environment Favors MLCT over the MC State in [Ru(bpy)2(Nicotine)2](Cl)2: A Case Study of Photolabile Ligands.

Ru(II)-complexes with photolabile ligands find a wide range of applications, e.g., in drug release and in the design of light-responsive interfaces. While light-driven ligand loss has been studied mechanistically in detail for complexes in solution, comparably few studies are present that investigate the process in a material context, i.e., in a rigid environment and in the absence of solvent. This paper adds to this underrepresented perspective by studying the excited-state dynamics of [Ru(bpy)2(nicotine)2] (Cl)2 (Ru-nico) as a model system in poly(methyl methacrylate) (PMMA) and polyacrylonitrile (PAN) matrices. Femtosecond transient absorption spectroscopy and time-resolved emission spectroscopy are employed to monitor the photodissociation of labile nicotine ligands in polymer environments. Photoexcitation within the metal-to-ligand charge transfer (MLCT) band leads to transient dissociation of the nicotine ligand when the complex is dissolved in water. However, optical excitation of the 1MLCT transition of the complexes embedded in polymer matrices does not result in photodissociation, likely due to the rigidity of the environment, which cannot solvate the undercoordinated complex after ligand dissociation and the dissociated ligand. These insights shed light on the role of the local environment when considering the photophysics of ligand loss from Ru(II)-polypyridyl complexes and, hence, their use in the light-activation of reactive molecular components in materials.

Investigation of the Effects of Different Phases of TiO2 Nanoparticles on PVA Membranes

Introduction: PVA/TiO2 nanocomposite membranes are prepared by solution casting technique where different phases of TiO2 nanoparticles like brookite, brookiterutile and rutile are dispersed in PVA matrix. Sol-gel method was employed to prepare TiO2 nanoparticles, while different phases of TiO2 have been obtained by controlling the calcination temperature. Methods: PVA/TiO2 nanocomposite membranes were characterized by XRD, FTIR, AFM, TEM, UV-visible and PL techniques. XRD results confirmed the presence of different phases of TiO2, exhibiting 3.3 nm, 8.4 nm, and 35.7 nm mean crystalline size. The XRD studies also confirmed that TiO2 nanoparticles became properly dispersed to the PVA matrix, leading to increased PVA crystallinity after doping of different phases of TiO2 nanoparticles. UV-visible analysis revealed an increase in absorption intensity and peak position shifts slightly towards longer wavelengths, which indicates that nanofillers tuned the band gap of PVA. The doping of the TiO2 (brookite) phase in the PVA matrix results in a decreased in PL intensity. Results: This suggests that the PVA/TiO2 (brookite) membrane exhibits a greater degree of photocatalytic activity in comparison to the other two composites. According to the FTIR investigation, the hydroxyl (OH) groups present in PVA interact with the dopants Ti+ ions via intra- and intermolecular hydrogen bonds to produce charge transfer complexes (CTC). The AFM study shows surface roughness details for PVA and PVA/TiO2 composite membranes. The average grain size of TiO2 nanoparticles calculated from TEM images is in good agreement with the grain size calculated by XRD. Conclusion: By adjusting the phase of TiO2 nanoparticles into PVA matrix, composites can be developed that are optimized for a variety of applications such as water purification, UV protection, self-cleaning surfaces, lithium-ion batteries, and optoelectronic devices.

Impact of electron acceptors on mechanochromism in carbazole-based charge transfer complexes

Impact of electron acceptors on mechanochromism in carbazole-based charge transfer complexes

Influence of Composition and Structure of Charge Transfer Complexes of Tioconazole on Their Spectral Properties and Anticancer Activity

Influence of Composition and Structure of Charge Transfer Complexes of Tioconazole on Their Spectral Properties and Anticancer Activity

Charge Transfer Interaction Dynamics between 2-Methyl-8-hydroxyquinoline and 2,4-Dinitrophenol: Synthesis, Spectroscopic Characterization, DNA Binding and DFT Studies

A novel charge transfer (CT) complex was formed by combining the electron-acceptor 2,4-dinitrophenol (DNP) with the electron-donor 2-methyl-8-hydroxyquinoline (MHQ). The complex obtained was further characterized using both experimental and theoretical methods. The Benesi-Hildebrand equation can be utilized to determine various spectroscopic physical measurements such as the molar absorptivity (εCT) and formation constant (KCT). The CT complex has a stoichiometry of 1:1. Multiple spectroscopic methods were employed to investigate the resultant solid compound. The existence of charge and proton transfer in the resultant complex was confirmed by FT-IR, 1H NMR, SEM-EDX and powder-XRD studies. An electron absorption spectroscopy examination was done to analyze the complex DNA binding capability. The resulting complex was determined to have an intercalative binding mechanism, with an intrinsic binding constant (Kb) value of 4.2 × 106 M-1. The experimental results were corroborated by performing theoretical calculations using DFT using a CAM-B3LYP/6-31G(d,p) basis set. The geometrical parameters, electrostatic potential maps (MEPs) and Mullikan charges were computed and examined in agreement with the experimental observations. In addition to electron transmission, the stability of the complex is influenced by the presence of a hydrogen bond.

Benzo[1,2-b:4,5-b’]dithiophene diethynyl bridged bimetallic ruthenium complexes: syntheses and characterization, (spectro)electrochemistry combined with theoretical calculations

We have constructed isomeric triruthenium ethynyl complexes 1 and 2 linked by benzo[1,2-b:4,5-b’]dithiophene. The electronic properties of 1 and 2 were compared by (spectro)electrochemical and theoretical calculations. DFT (density functional theory) fully-optimized structures 1 and 2 showed that the ruthenium terminal groups both exhibit a similar pseudo-octahedral configuration as reported for the crystal structure of 1. With step-by-step oxidation, the bond length of Ru-C decreases and the bond length of C≡C increases, which indicated that the complexes undergo a transition from Ru-C≡C to Ru = C = C. The electrochemical results of 1 and 2 featured two consecutive single-electron redox processes, and the ΔE value of 2 (329 mV) was significantly higher than that of 1 (140 mV). The near-IR broad absorptions of 2 + from UV-Vis-NIR spectroelectrochemistry exhibited a blue shift relative to that of 1 +, which could be attributed to MLCT (metal to ligand charge transfer) absorptions and confirmed by TDDFT (time dependent) calculations. The results suggested that the bridge ligands are involved in the redox process. The ν(C≡C) stretch of 2 + from IR spectroelectrochemistry exhibited a strong single peak at 1969 cm-1, while the isomer 1 + showed three asymmetric peaks. These results showed excellent charge delocalization ability of 2.

Wide-range tunable circularly polarized luminescence in triphenylamine supramolecular polymers via charge-transfer complexation

Wide-range tunable circularly polarized luminescence in triphenylamine supramolecular polymers via charge-transfer complexation

Development of novel DNA aptamers and colorimetric nanozyme aptasensor for targeting multi-drug-resistant, invasive Salmonella typhimurium strain SMC25

Invasive, biofilm-forming Non-typhoidal Salmonella (iNTS), propagating through the global food and water supply chain, presents a significant risk to food safety and public health. Developing a robust detection system is crucial for enabling point-of-care, affordable, and equipment-free identification of this pathogen throughout the supply chain. In this study, we screened a novel pool of ssDNA aptamers specific to a multidrug resistant iNTS strain SMC25, previously isolated from Indian poultry products in our earlier research. Through 13 rounds of whole-cell SELEX, we identified, characterized, and selected seven full-length aptamers (ST18, ST19, ST25, ST28, ST29, ST31, and ST32). Flow cytometric analysis reveals superior binding of ST25, ST28, ST29, and ST31. These aptamers were translated onto Nanozyme-based aptasensing system for efficient, cost-effective detection of SMC25. This system harnesses the aptamer-mediated, reversible peroxidase-like activity of gold nanoparticles (GNPs) to oxidize the TMB substrate into a one-electron oxidation state, resulting in a blue-colored Diamine charge transfer complex (DCTC). The catalytic process, coupled with GNP aggregation, induces a visible color change in the test mixture from ruby-red to blue. Post-SELEX truncations identified the optimal aptamer sequence (T_ST31), which selectively detected SMC25 in water with a limit of detection (LOD) of ∼10⁴ CFU/mL. Lower concentrations (10 CFU/mL) of SMC25 could be detected after non-selective enrichment within 120 min. This research introduces a novel pool of iNTS-specific aptamers along with a cost-effective (0.25 USD per sample) solution for colorimetric detection by the naked eye.

Photocatalysis of Adsorbed Catechol on Degussa P25 TiO2 at the Air-Solid Interface.

Semiconductor photocatalysis with commercial TiO2 (Degussa P25) has shown significant potential in water treatment of organic pollutants. However, the photoinduced reactions of adsorbed catechol, a phenolic air pollutant from biomass burning and combustion emissions, at the air-solid interface of TiO2 remain unexplored. Herein we examine the photocatalytic decay of catechol in the presence of water vapor, which acts as an electron acceptor. Experiments under variable cut-off wavelengths of irradiation (λcut-off ≥ 320, 400, and 515 nm) distinguish the mechanistic contribution of a ligand-to-metal charge-transfer (LMCT) complex of surface chemisorbed catechol on TiO2. The LMCT complex injects electrons into the conduction band of TiO2 from the highest occupied molecular orbital of catechol by visible light (≥2.11 eV) excitation. The deconvolution of diffuse reflectance UV-visible spectral bands from LMCT complexes of TiO2 with catechol, o-semiquinone radical, and quinone and the quantification of the evolving gaseous products follow a consecutive kinetic model. CO2(g) and CO(g) final oxidation products are monitored by gas chromatography and Fourier-transform infrared spectroscopy. The apparent quantum efficiency at variable λcut-off are determined for reactant loss (Φ- TiO2/catechol = 0.79 ± 0.19) and product growth ΦCO2 = 0.76 ± 0.08). Spectroscopic and electrochemical measurements reveal the energy band diagram for the LMCT of TiO2/catechol. Two photocatalytic mechanisms are analyzed based on chemical transformations and environmental relevance.

A Comprehensive Multireference Study of Excited-State Ni-Br Bond Homolysis in (dtbbpy)NiII(aryl)(Br).

The mechanism of visible light-driven Ni-C(aryl) bond homolysis in (2,2'-bipyridine)NiII(aryl)(halide) complexes, which play a crucial role in metallaphotoredox catalysis for cross-coupling reactions, has been well studied. Differently, the theoretical understanding of Ni-halide bond homolysis remains limited. In this study, we introduce a novel electronic structural framework to elucidate the mechanisms underlying photoinduced Ni-Br bond rupture in the (dtbbpy)NiII(aryl)(Br) complex. Using multireference ab initio calculations, we characterized the excited state potential energy surfaces corresponding to metal-to-ligand charge transfer (MLCT) and ligand-to-metal charge transfer (LMCT). Our calculations reveal that the Ni-Br dissociation, triggered by an external photocatalyst, begins with the promotion of Ni(II) to a 1MLCT excited state. This state undergoes intersystem crossing with repulsive triplet surfaces corresponding to the 3MLCT and Br-to-Ni 3LMCT states, resulting in Ni-Br bond breaking via the Dexter energy transfer mechanism. In the absence of a photocatalyst, the photoexcited Ni(II) favors Ni-C(aryl) homolysis, whereas the presence of a photocatalyst promotes Ni-Br dissociation. The Ni(III) species, resulting from the oxidation of Ni(II) by the photocatalyst, was found to be unproductive toward Ni-Br or Ni-C(aryl) activation.

Solvent assisted mechanochemical synthesis, antimicrobial and antioxidant studies of Ni2+, Mn2+, Cr<sup>2+</sup> , and Cu<sup>2+</sup> Metal complexes of some ligands derived from l-histidine and l-alanine

Mechanochemistry enables rapid, quantitative reactions to occur at or close to 27℃. It is a one-step process that allows for reactant homogenization, product nucleation, and particle growth. These processes use little or no solvent, making them less wasteful and more environmentally friendly than solvent-based reactions. Ni2+ , Mn2+, Cr2+and Cu2+ metal ions were synthesized by grinding in an agate mortar with pestle using ligands derived from amino acids (Histidine &Alanine) which were further synthesized to form complexes. The entire experiment was carried out by solvent solvent-assisted mechanochemical process and ethanol was used as liquid liquid-assisted solvent. The complexes were characterized by IR spectroscopy, U-V spectroscopy, X-ray analysis, melting point, solubility test, and conductivity measurement. The Solubility test showed that the complexes are soluble in DMSO, DMF, and ethanol and are insoluble in both hexane and tetrachloromethane. The molar conductivity values are in the range of (6.05-28.56) Ω-1cm2mol-1 ) indicating the complexes behave as non-electrolytes. IR analysis showed a vibrational frequency band observed at (1620-1625) cm-1 which is assigned to the ʋ(C=N) of the azomethine, also the new bands M=N, M=O indicate the coordination reaction between the metal and the ligands. The UV visible analysis shows various transitions, the metal complexes showed adsorption bands at λ of 420 and 575nm respectively because of the ligand-to-metal charge transfer (LMCT). The XRD analysis showed that there was a change in phase between the starting material and the product which indicate that a reaction occurred, also the nature of the spectra showed that the compounds are all crystalline. The Antimicrobial activity showed that both the complexes and the ligands have good activity against the bacterial isolates. Antioxidant activity was also tested and the compound appeared to have moderate scavenging activities compared to the reference used. The values indicated that the activities are more pronounced when coordinated with metal ions.

Ancillary Ligand-Promoted Charge Transfer in Bis-indole Pyridine Ligand-Based Nickel Complexes.

There is growing demand for the utilization of first-row transition metal complexes in light-driven processes instead of their conventional noble metal counterparts due to the greater sustainability of first-row transition metal complexes. However, their major drawback is the ultrafast lifetime of the electronic excited states of these first-row transition metal complexes, particularly those of d8 square-planar systems such as Ni(II) complexes, wherein low-lying metal-centered (MC) states provide the deactivation pathway. To increase the excited-state lifetime and broaden their applications, it is important to develop sterically bulky, strong field ligands with low-lying π* orbitals and a highly σ-donating nature to augment the energy of MC states. The current strategy relies on synthetically carbene-based ligands, which are substitutionally cumbersome and act as σ-donors only. In this work, we introduce a bis-indole pyridine (H2BIP) ligand framework, whose dianionic congener (BIP) demonstrates the ability to form stronger covalent bonds with a Ni(II) center compared to neutral donors like carbene and its effect on the complex to produce a less distorted excited-state structure. When conjoined with ancillary ligands such as pyridine or lutidine, the BIP ligand orchestrates the formation of low-energy 3CT states, which decay in ∼40 ps.

Sunlight-Driven Direct/Mediated Electron Transfer for Cr(VI) Reductive Sequestration on Dissolved Black Carbon-Ferrihydrite Coprecipitates.

Surface runoff horizontally distributed chromium (Cr) pollution into various surface environments. Sunlight is a vital factor for the Cr cycle in the surface environment, which may be affected by photoactive substances such as ferrihydrite (Fh) and dissolved black carbon (DBC). Herein, sunlight-driven transformation dynamics of Cr species on DBC-Fh coprecipitates were studied. Under sunlight, the removal of aqueous Cr(VI) by DBC-Fh coprecipitates occurred through sunlight-driven reductive sequestration including adsorption, followed by surface reduction (pathway 1) and aqueous reduction, followed by precipitation (pathway 2). Additionally, coprecipitates with a higher DBC content exhibited a more effective reduction of both adsorbed (kapp,S_red) and aqueous Cr(VI) (kapp,A_red). Photoelectrons facilitated Cr(VI) reduction through direct electron transfer; notably, electron donating DBC promoted the production of photoelectrons by consuming photogenerated holes. Photogenerated Fe(II) species (mineral-phase and aqueous Fe(II)) mediated electron transfer for Cr(VI) reduction, which was reinforced via a ligand-to-metal charge transfer (LMCT) process between DBC-organic ligands and mineral Fe(III). Furthermore, ·O2- also mediated Cr(VI) reduction, although this impact was limited. Overall, this study demonstrates that photoelectrons and photogenerated electron mediators play a crucial role in Cr(VI) reductive sequestration on DBC-Fh coprecipitates, providing new insights into the geochemical cycle of Cr pollution in sunlight-influenced surface environments.

Low-Dispersity Polymers via Free Radical Alternating Copolymerization: Effects of Charge-Transfer-Complexes.

Alternating copolymers are crucial for diverse applications. While dispersity (Ð, also known as molecular weight distribution, MWD) influences the properties of polymers, achieving low dispersities in alternating copolymers poses a notable challenge via free radical polymerizations (FRPs). In this work, we demonstrated an unexpected discovery that dispersities are affected by the participation of charge transfer complexes (CTCs) formed between monomer pairs during free radical alternating copolymerization, which have inspired the successful synthesis of various alternating copolymers with low dispersities (>30 examples, Ð=1.13-1.39) under visible-light irradiation. The synthetic method is compatible with binary, ternary and quaternary alternating copolymerizations and is expandable for both fluorinated and non-fluorinated monomer pairs. DFT calculations combined with model experiments indicated that CTC-absent reaction exhibits higher propagation rates and affords fewer radical terminations, which could contribute to low dispersities. Based on the integration of Monte Carlo simulation and Bayesian optimization, we established the relationship map between FRP parameter space and dispersity, further suggested the correlation between low dispersities and higher propagation rates. Our research sheds light on dispersity control via FRPs and creates a novel platform to investigate polymer dispersity through machine learning.

Investigating the effect of Cu underlayer and FTO etching towards photoelectrochemical performance enhancement of Cu2O photoelectrode

Cuprous oxide (Cu2O) exhibits potential as a photoactive material for photoelectrochemical water splitting, owing to its appropriate bandgap, efficient charge carrier separation, and ability to enhance solar-driven hydrogen production. This study investigates the influence of substrate etching, Cu underlayer and Cu2O electrodeposition time, and annealing time on enhancing the photoelectrochemical (PEC) performance. Electrodeposition and thermal oxidation techniques were used to fabricate the Cu2O/Cu/FTOe-A photocathode. It has been observed that FTO etching improves adhesion, light transmission, and efficiency. A Cu underlayer also impacts the PEC performance, wherein an ideal thickness of Cu leads to enhanced PEC performance. This study also focuses on the annealing time that leads to CuO layers and nanowires forming on the Cu2O surface. The structural and chemical changes before and after annealing are confirmed via XRD, XPS, AFM and FESEM analyses. UV–Vis analysis also reveals that the presence of Cu underlayer, FTO etching, and the annealing process affect the electrical properties and light absorption capacities of the Cu2O photoelectrode. Electrochemical impedance analysis (EIS) and Mott-Schottky analysis have provided insights into the enhanced charge transfer properties and band bending in the Cu2O/Cu/FTOe-A, resulting in enhanced PEC performance. Overall, this study provides significant insights into the understanding and enhancement of Cu2O/Cu/FTOe-A photocathodes for potential use in PEC water splitting applications.

Energy transfer-mediated multiphoton synergistic excitation for selective C(sp3)–H functionalization with coordination polymer

Activation and selective oxidation of inert C(sp3)–H bonds remain one of the most challenging tasks in current synthetic chemistry due to the inherent inertness of C(sp3)–H bonds. In this study, inspired by natural monooxygenases, we developed a coordination polymer with naphthalenediimide (NDI)-based ligands and binuclear iron nodes. The mixed-valence FeIIIFeII species and chlorine radicals (Cl•) are generated via ligand-to-metal charge transfer (LMCT) between FeIII and chlorine ions. These Cl• radicals abstract a hydrogen atom from the inert C(sp3)–H bond of alkanes via hydrogen atom transfer (HAT). In addition, NDI converts oxygen to 1O2 via energy transfer (EnT), which then coordinates to FeII, forming an FeIV = O intermediate for the selective oxidation of C(sp3)–H bonds. This synthetic platform, which combines photoinduced EnT, LMCT and HAT, provides a EnT-mediated parallel multiphoton excitation strategy with kinetic synergy effect for selective C(sp3)–H oxidation under mild conditions and a blueprint for designing coordination polymer-based photocatalysts for C(sp3)–H bond oxidation.

N-Halosuccinimide-CeCl3 Transient Charge-Transfer Complexes as Semi Heterogeneous Photocatalyst in Cyclization of N-Propargylamides.

In this work, we used photoinert anhydrous cerium(III) chloride, to form a transient charge-transfer (CT) complex with NXS (N-bromosuccinimide or NBS and N-iodosuccinimide or NIS) in acetonitrile. These transient CT complexes acted as a semi-heterogeneous photocatalyst. These complexes allowed the Ce(III) ions to absorb light, turning them into strong electron donors that transferred electrons to NXS. This created halide radicals from NXS radical anions, helping to turn N-propargylamides into oxazole aldehydes. Experiments with DMPO and spin-trapping showed that a radical-based mechanism followed a single electron transfer (SET) pathway. Notably, CeCl3 was reused after the reaction without much decomposition, as it was regenerated and separated through simple filtration.