Copper Phenanthroline Research Articles

Visible‐Light‐Mediated Copper(I)‐Catalyzed Regiospecific Amino‐Hydroxylation and Amino‐Alkoxylation of Vinyl Arenes

Aminohydroxylation of alkene is an important method for synthesizing 1,2‐amino alcohols, which are found in natural products, pharmaceutically active compounds and several marketed drugs. Herein, we report the development of visible‐light mediated copper‐catalyzed aminohydroxylation and aminoalkoxylation of alkenes. In contrast to expensive iridium, ruthenium, or organic‐dyes based photocatalysts, this protocol takes advantage of economical copper phenanthroline complex as a photocatalyst for the generation of N‐centred radical from N‐amino pyridinium salt. Furthermore, this protocol features a mild reaction conditions, broad substrate scope, and regiospecific.

Cooperative, Close and Remote Steric Effects on the Structural and Optical Properties of Copper(I) Bis‐Phenanthroline Complexes

AbstractThe synthesis as well as the structural, optical and computational characterization of seven new highly hindered homoleptic copper(I) phenanthroline complexes (namely C1–C7) is reported along with the comparison with the benchmark derivatives. Despite limited steric hindrance in direct proximity of the copper(I) coordination site, X‐ray structures show that the higher hindered derivatives of the series display a more optimal tetrahedral geometry with minimal D2 symmetry distortion. A novel remote control of the geometry, with steric hindrance away from the coordination site, leads to a favorable arrangement as demonstrated by structural and computational data. In addition, electrochemical and steady‐state and time‐resolved photophysical studies are presented which further support the beneficial effects on the ground‐state redox and excited‐state properties when both remote and close steric effects are exploited. Indeed, both an increase of the photoluminescence quantum yield and a prolongation of the excited state lifetime is observed for the highly‐substituted derivative C6 compared to benchmark counterparts on account of the reduced excited‐state flattening distortions imparted by the additional steric constraints.

Encapsulation of copper phenanthroline within horse spleen apoferritin: characterisation, cytotoxic activity and ability to retain temozolomide.

Protein capsules are promising drug delivery vehicles for cancer research therapies. Apoferritin (AFt) is a self-assembling 12 nm diameter hollow nanocage with many desirable features for drug delivery, however, control of drug retention inside the protein cage remains challenging. Here we report the encapsulation of copper(ii)-1,10-phenanthroline (Cu(phen)) within the horse spleen AFt (HSAFt) nanocage, by diffusion of the metal through the pores between the protein subunits. Transmission electron microscopy revealed the formation of organised copper adducts inside HSAFt, without affecting protein integrity. These structures proved stable during storage (>4 months at -20 °C). Exposure to physiologically relevant conditions (37 °C) showed some selectivity in cargo release after 24 h at pH 5.5, relevant to the internalisation of AFt within the endosome (60% release), compared to pH 7.4, relevant to the bloodstream (40% release). Co-encapsulation of temozolomide, a prodrug used to treat glioblastoma multiforme, and Cu(phen) enabled entrapment of an average of 339 TMZ molecules per cage. In vitro results from MTT and clonogenic assays identified cytotoxic activity of the Cu(phen), HSAFt-Cu(phen) and HSAFt-Cu(phen)-TMZ adducts against colorectal cancer cells (HCT-116) and glioblastoma cells (U373V, U373M). However, the presence of the metal also contributed to more potent activity toward healthy MRC5 fibroblasts, a result that requires further investigation to assess the clinical viability of this system.

Heterogenized Molecular Electrocatalyst Based on a Hydroxo-Bridged Binuclear Copper(II) Phenanthroline Compound for Selective Reduction of CO2 to Ethylene.

Molecular copper catalysts have emerged as promising candidates for the electrochemical reduction of CO2 . Notable features of such systems include the ability of Cu to generate C2+ products and the well-defined active sites that allow for targeted structural tuning. However, the frequently observed in situ formation of Cu nanoclusters has undermined the advantages of the molecular frameworks. It is therefore desirable to develop Cu-based catalysts that retain their molecular structures during electrolysis. In this context, a heterogenized binuclear hydroxo-bridged phenanthroline Cu(II) compound with a short Cu···Cu distance is reported as a simple yet efficient catalyst for electrogeneration of ethylene and other C2 products. In an aqueous electrolyte, the catalyst demonstrates remarkable performance, with excellent Faradaic efficiency for C2 products (62%) and minimal H2 evolution (8%). Furthermore, it exhibits high stability, manifested by no observable degradation during 15 h of continuous electrolysis. The preservation of the atomic distribution of the active sites throughout electrolysis is substantiated through comprehensive characterizations, including X-ray photoelectron and absorption spectroscopy, scanning and transmission electron microscopy, UV-vis spectroscopy, as well as control experiments. These findings establish a solid foundation for further investigations into targeted structural tuning, opening new avenues for enhancing the catalytic performance of Cu-based molecular electrocatalysts.

Copper phenanthroline for selective electrochemical CO2 reduction on carbon paper.

We report a series of structurally relevant copper phenanthroline complexes as pre-catalysts for highly selective electrocatalytic reduction of CO2 to C2 products using inexpensive carbon paper electrodes. The Cu complexes with non-substituted phenanthroline promote the production of ethylene with a high faradaic efficiency of 71.2%, while the one with pyridinium-functionalized ligands is more selective for ethanol. The C2 selectivity can be effectively tuned by increasing the number of coordinated phenanthrolines and remains high at a wide range of potentials.

Cross-Linking and Functional Analyses for Dimerization of a Cysteine Mutant of Glycine Transporter 1.

Glycine transporter 1 (GlyT1) is responsible for the reuptake of glycine, which regulates glutamate signaling as a co-agonist with N-methyl-D-aspartic acid (NMDA) receptors in the excitatory synapse and has been proposed to be a potential target in the development of therapies for a broad range of disorders of the central nervous system. Despite significant progress in characterizing structure and transport mechanism of the transporter, the regulation of transport function through oligomerization remains to be understood. In the present work, association of two forms of GlyT1 into dimers and higher order oligomers was detected by coimmunoprecipitation. To investigate functional properties of dimers of a GlyT1 cysteine mutant L288C, we performed oxidative cross-linking of the positioned cysteine residues in extracellular loop 3 (EL3) near the extracellular end of TM6. By analyzing the effect of copper phenanthroline (CuP)-induced dimerization on transport function, cross-linking of L288C was found to inhibit transport activity. In addition, an intramolecular ion pair Lys286-Glu289 was revealed to be critical for stabilizing EL3 in a conformation that modulates CuP-induced dimerization and transport function of the GlyT1 L288C mutant. Furthermore, the influence of transporter conformation on GlyT1 L288C dimerization was investigated. The substrate glycine, in the presence of both Na+ and Cl-, significantly reduced oxidative cross-linking, suggesting a large-scale rotation of the bundle domain during substrate transport impairs interfacial interactions between L288C protomers. The present study provides new insights into structural and functional elements regulating GlyT1 transport activity through its dimerization or oligomerization.

Harnessing Intermolecular Interactions to Promote Long-Lived Photoinduced Charge Separation from Copper Phenanthroline Chromophores

Facilitating photoinduced electron transfer (PET) while minimizing rapid charge-recombination processes to produce a long-lived charge-separated (CS) state represents a primary challenge associated with achieving efficient solar fuel production. Natural photosynthetic systems employ intermolecular interactions to arrange the electron-transfer relay in reaction centers and promote a directional flow of electrons. This work explores a similar tactic through the synthesis and ground- and excited-state characterization of two Cu(I)bis(phenanthroline) chromophores with homoleptic and heteroleptic coordination geometries and which are functionalized with negatively charged sulfonate groups. The addition of sulfonate groups enables solubility in pure water, and it also induces assembly with the dicationic electron acceptor methyl viologen (MV2+) via bimolecular, dynamic electrostatic interactions. The effect of the sulfonate groups on the ground- and excited-state properties was evaluated by comparison with the unsulfonated analogues in 1:1 acetonitrile/water. The excited-state lifetimes for all sulfonated complexes are similar to what we expect from previous literature, with the exception of the sulfonated heteroleptic complex whose metal-to-ligand charge-transfer (MLCT) lifetime in water has two components that are fit to 10 and 77 ns. For the sulfonated complexes, we detected reduced MV+• in both solvent environments following MLCT excitation, but control measurements in 1:1 acetonitrile/water with the unsulfonated analogues showed no PET to MV2+, indicating that electrostatically driven supramolecular assemblies of the sulfonated complexes with MV2+ facilitate the observed PET. Additionally, the strength of the intermolecular interactions driving the formation of these assemblies changes drastically with the solvent environment. In 1:1 acetonitrile/water, PET occurred from both sulfonated complexes with quantum yields (ΦET) of 2-3% but increased to a remarkable 98% for the sulfonated heteroleptic complex with a 3 μs CS-state lifetime in water.

Cover Feature: Encapsulation Enhances the Catalytic Activity of C‐N Coupling: Reaction Mechanism of a Cu(I)/Calix[8]arene Supramolecular Catalyst (ChemCatChem 20/2022)

The Cover Feature illustrates the C−N coupling of aniline and aryl bromide in the cavity of a supramolecular copper phenanthroline calix[8]arene catalyst. In their Research Article, R. A. Talmazan, J. Refugio Monroy and co-workers showed how encapsulation of an otherwise poor Cu(I) phenanthroline catalyst by calix[8]arene enhances the catalytic activity for C−N coupling between aryl amines and aryl halides. Yields up to 92% were achieved with low catalyst loadings (2.5% mol). A multiscale computational protocol based on DFT and MD simulations revealed the origins of the drastically improved catalytic performance. More information can be found in the Research Article by R. A. Talmazan, J. Refugio Monroy and co-workers.

An Evolutionarily Conserved Residue in ABCG2 Regulates the Transport Cycle and Inhibitor Activity

ABCG2 is a medically significant ATP‐binding cassette (ABC) transporter restricting the cellular penetration of more than 200 toxins and drugs, as well as promoting physiological detoxification and multidrug resistance in cancers. Although ABCG2 cryo‐EM structural studies reveal an overlap between substrate and inhibitor binding sites in the ABCG2 binding pocket, it is unknown how much these substrate and inhibitor interactions will translate into functional knowledge that is exploitable in live cells.We generated multiple single point‐mutations in the residues of the ABCG2 binding pocket to determine if there is a relationship between binding (defined by thermal shift stabilization) and transport. Unexpectedly, the relationship between substrate‐induced thermal stabilization and transport was poor and an alanine substitution in a highly conserved asparagine residue in ABCG2 markedly impaired substrate‐induced thermal stabilization, but paradoxically enhanced substrate transport. To determine if the substitution altered ABCG2 conformational response to substrate binding, we used live cells and performed copper phenanthroline induced disulfide cross‐linking analysis on cells expressing the appropriate cysteine substituted ABCG2 (1). Consistent with the enhanced transport, the substitution promoted a substrate‐induced conformational change from an inward‐ to an outward‐facing ATP‐bound state. Molecular dynamics (MD) simulations using an ABCG2 structure (PDB: 6VXH) suggested a mechanism for this enhanced transport by the alanine mutant: disruption of a water‐bridge interaction with the asparagine residue coupled with an alteration in contacts with certain residues in the binding pocket. We next investigated if this alanine substitution affected inhibitor binding and transport inhibition. The substitution strongly reduced inhibitor‐induced thermal stabilization and transport inhibition. The disulfide cross‐linking analysis revealed that the substitution abolished the ability of many inhibitors to block the transition to an outward‐facing state. For these inhibitors, MD simulations revealed that the substitution disrupted a hydrogen bond interaction with the asparagine residue and impacted inhibitor interactions with multiple residues. Overall these changes indicate that inhibitors have mostly lost their ability to act like “wedges” to lock ABCG2 into an inward‐facing conformation.These findings reveal that an evolutionarily conserved asparagine residue, in the binding pocket, appears to have a key role in regulating the conformational dynamics of ABCG2.Reference:(1) Orlando, B. J. and Liao, M., ABCG2 transports anticancer drugs via a closed‐to‐open switch. Nat. Commun., 11, 2264 (2020)

Hybrid Catalysts from Copper Biosorbing Bacterial Strains and Their Recycling for Catalytic Application in the Asymmetric Addition Reaction of B2(pin)2 on α,β-Unsaturated Chalcones

The recycling of heavy metal contaminants from wastewater as a source of valuable products perfectly fits with the principles of a Circular Economy system in view of restoring pollutants back into the system endowed with new social and economic benefits. Heavy metals are often present in such a low concentration that it makes the removal efficiency difficult to realize through the conventional physicochemical methods with high selectivity. Biosorption, conversely, by EPSs (extracellular polymeric substances) produced by several bacterial cells’ strains, is gaining a great deal of attention as an economic, efficient and sustainable depolluting process of wastewater from metal cations such as copper. Metal coordination to EPS components was thus deeply investigated by 1H NMR titration experiments. The 1,10–Phenanthroline–copper complex was exploited for quantifying the ability of different strains to sequester copper by a practical UV-Vis spectrophotometric method. The obtained data distinguished Serratia plymuthica strain SC5II as the bacterial strain displaying copper-adsorbing properties higher than any other, with Stenotrophomonas sp. strain 13a resulting in the worst one. Different analytical techniques, i.e., Dynamic Light Scattering (DLS), FT-IR analysis and SEM spectroscopy were thus employed to rationalize these results. Finally, the obtained copper chelates were successfully employed as hybrid catalysts in the asymmetric boron addition to α,β-unsaturated chalcones for the synthesis of valuable pharmaceutical intermediates, thus placing waste management in a new circular perspective.

A Heterogenized Copper Phenanthroline System to Catalyze the Oxygen Reduction Reaction.

Upon the electrochemical reduction of an in situ generated 5‐diazo‐1,10‐phenanthroline ion, phenanthroline was covalently attached to a gold electrode. The grafted molecules act as a ligand when brought in contact with a copper‐containing electrolyte solution. As the ligands are limited in spatial movement, the exclusive formation of the active species with only one phenanthroline ligand coordinated was expected. The in situ generated complexes have been investigated for activity in the oxygen reduction reaction, for which an overpotential of 800 mV is observed. During catalysis, initially a thick copper layer is formed on top of an organic layer that is still present on the gold surface. Upon deterioration of the organic layer underneath the copper over time, the amount of copper on the electrode and thereby the electrocatalytic activity decreases.

Isolation of monomeric copper(II) phenolate selenoether complexes using chelating ortho-bisphenylselenide-phenolate ligands and their electrocatalytic hydrogen gas evolution activity.

A series of novel copper(II) phenolate selenoether complexes have been synthesized and structurally characterized for the first time from copper(I) phenanthroline and various substituted ortho-bisphenylselenide-phenol chelating ligands. The synthesized complexes exhibit Jahn-Teller distortion in their geometry and varied from distorted square planar to distorted octahedral by varying the substituent in the bis-selenophenolate ligand. The synthesized complexes electrocatalyze the hydrogen evolution reaction (HER) with a faradaic efficiency of up to 89%, and it was observed that the distorted square pyramidal geometry is the optimum geometry for the maximum efficiency of these copper complexes.

A novel chiral carbon nanocomposite based on cellulose gum modifying chiral tri-electrode system for the enantiorecognition of tryptophan

Phenanthroline copper (PhenCu) prepared via complex reaction was inserted into graphene oxide (GO) layers via π-π interaction and reduced to form the substrate material (rGO-PhenCu). A chiral carbon nanocomposite (rGO-PhenCu-CMC) was elaborately fabricated by modification of carboxymethyl cellulose sodium (CMC) via electrostatic interaction on rGO-PhenCu. Herein, many characterization methods such as FT-IR, SEM and XPS showed the successful preparation of rGO-PhenCu-CMC. Combining the ligand exchange on rGO-PhenCu with three-point force model on asymmetric CMC, the chiral electrochemical sensor based on rGO-PhenCu-CMC was successfully used for enantioselective recognition of tryptophan (Trp), and the enantioselectivity of the proposed sensor (rGO-PhenCu-CMC/GCE) has significantly improved via synergistic interaction. The results showed that the rGO-PhenCu-CMC showed better compatibility for l-Trp than d-Trp owing to the existance of steric hindrance.

The co-crystal of copper(II) phenanthroline chloride complex hydrate with p-aminobenzoic acid: structure, cytotoxicity, thermal analysis, and DFT calculation

The co-crystal of copper(II) phenanthroline chloride complex hydrate with p-aminobenzoic acid: structure, cytotoxicity, thermal analysis, and DFT calculation

Substituent effects on the photophysical properties of 2,9-substituted phenanthroline copper(I) complexes: a theoretical investigation.

The electronic and nuclear structures of a series of [Cu(2,9-(X)2 -phen)2 ]+ copper(I) complexes (phen=1,10-phenanthroline; X=H, F, Cl, Br, I, Me, CN) in their ground and excited states are investigated by means of density functional theory (DFT) and time-dependent (TD-DFT) methods. Subsequent Born-Oppenheimer molecular dynamics is used for exploring the T1 potential energy surface (PES). The T1 and S1 energy profiles, which connect the degenerate minima induced by ligand flattening and Cu-N bond symmetry breaking when exciting the molecule are calculated as well as transition state (TS) structures and related energy barriers. Three nuclear motions drive the photophysics, namely the coordination sphere asymmetric breathing, the well-documented pseudo Jahn-Teller (PJT) distortion and the bending of the phen ligands. This theoretical study reveals the limit of the static picture based on potential energy surfaces minima and transition states for interpreting the luminescent and TADF properties of this class of molecules. Whereas minor asymmetric Cu-N bonds breathing accompanies the metal-to-ligand-charge-transfer re-localization over one or the other phen ligand, the three nuclear movements participate to the flattening of the electronically excited complexes. This leads to negligible energy barriers whatever the ligand X for the first process and significant ligand dependent energy barriers for the formation of the flattened conformers. Born-Oppenheimer (BO) dynamics simulation of the structural evolution on the T1 PES over 11 ps at 300 K confirms the fast backwards and forwards motion of the phenanthroline within 200-300 fs period and corroborates the presence of metastable C2 structures.

Hydroxyl Radical Generation by the H2O2/CuII/Phenanthroline System under Both Neutral and Alkaline Conditions: An EPR/Spin-Trapping Investigation

The copper–phenanthroline complex CuI(Phen)2 was the first artificial nuclease studied in biology. The mechanism responsible for this activity involves CuII(Phen)2 and H2O2. Even if H2O2/Cu systems have been extensively studied in biology and oxidative chemistry, most of these studies were carried out at physiological pH only, and little information is available on the generation of radicals by the H2O2/CuII-Phen system. In the context of paper pulp bleaching to improve the bleaching ability of H2O2, this system has been investigated, mostly at alkaline pH, and more recently at near-neutral pH in the case of dyed cellulosic fibers. Hence, this paper aims at studying the production of radicals with the H2O2/CuII-Phen system at near-neutral and alkaline pHs. Using the EPR/spin-trapping method, HO• formation was monitored to understand the mechanisms involved. DMPO was used as a spin-trap to form DMPO–OH in the presence of HO•, and two HO• scavengers were compared to identify the origin of the observed DMPO–OH adduct, as nucleophilic addition of water onto DMPO leads to the same adduct. H2O2 decomposition was enhanced by the addition of CuII–Phen (and only slightly by addition of CuSO4), reaching a level similar to the Fenton reagent at near-neutral pH. This evidences the role of Phen, which improves the effect of CuII by tuning the electronic structure and structural properties of the corresponding CuII complexes.

Synthesis and characterization of nanoclusters: Inorganic-organic hybrid copper and cobalt containing arsenotungstates(III) with lone pair on heteroatom incorporating bidentate N-donating ligands

Three inorganic-organic hybrid nanoclusters of copper and cobalt containing arsenotungstates with lone pair on heteroatom have been synthesized under mild reactions conditions. All the compounds have been characterized by single crystal X-ray diffraction, Fourier transform infrared, UV/visible spectroscopy, thermogravimetric and field emission scanning electron microscopic (FE-SEM) analysis. The compound [NaRb{Cu(phen) (H 2 O) 2 Cl} 2 ][{Cu(phen)(H 2 O)} 2 {Cu(phen) (H 2 O)Cl} 2 {Cu 2 As 2 W 19 O 67 (H 2 O)] (1a) is a sandwiched type arsenotungstate with two copper atoms in square planar environment in the belt region. The polyanion- 1 is decorated by four copper phenanthroline complexes through a terminal oxygen atom of the polyanion. In addition, two other cobalt containing inorganic-organic hybrid lone pair containing arsenotungstates(III) with 1,10-phenanthroline [NaRbCo(phen) 3 ][{Co(phen)(H 2 O) 3 }CoAs 2 W 20 O 67 (H 2 O) 3 ] (2a) and 2,2’-bipyridine[Na 3 RbCo(2,2-bipy) 3 ][CoAs 2 W 20 O 67 (H 2 O) 3 ] (3a) has also been synthesized under mild conditions. The polyanion ( 2 ) is a mono cobalt substituted sandwiched type structure that is decorated by a cobalt phenanthroline complex attached to the polyanion through a terminal oxygen atom. Meanwhile the other complex ( 3 ) is also a monocobalt substituted sandwiched type structure which contains a cobalt 2,2’-bipyridine complex in the cationic part. Polyanion- 1 shows intermolecular π-π stacking interaction between the phenanthroline ligand in the cationic part and one that is attached directly to the polyanion. The compounds are also characterized by FE-SEM analysis and the compound 3a shows ultra- smooth cuboids with grain size in the range of 1 to several micrometer though some very small irregular particles with the size of a few micrometer were also observed.

On the interplay of solvent and conformational effects in simulated excited-state dynamics of a copper phenanthroline photosensitizer.

Copper(i) bis-phenanthroline complexes represent Earth-abundant alternatives to ruthenium-based sensitizers for solar energy conversion and photocatalysis. Improved understanding of the solvent-mediated excited-state structural dynamics can help optimize their photoconversion efficiency. Through direct dynamics simulations in acetonitrile and excited-state minimum energy path calculations in vacuum, we uncover the mechanism of the photoinduced flattening motion of the prototypical system [Cu(dmphen)2]+ (dmphen = 2,9-dimethyl-1,10-phenanthroline). We find that the ligand distortion is a two-step process in acetonitrile. The fast component (∼110 fs) is due to spontaneous pseudo Jahn-Teller instability and is largely solvent independent, while the slow component (∼1.2 ps) arises from the mutual interplay between solvent molecules closely approaching the metal center and rotation of the methyl substituents. These results shed new light on the influence of a donor solvent such as acetonitrile and methyl substituents on the flattening dynamics of [Cu(dmphen)2]+.

Theoretical and Experimental Reactivity Predictors for the Electrocatalytic Activity of Copper Phenanthroline Derivatives for the Reduction of Dioxygen

We have systematically studied the catalytic activity of a series of substituted bisphenanthroline Cu complexes adsorbed on glassy carbon electrodes for the oxygen reduction reaction (ORR) in aqueous media. The aim of this work is to test reactivity descriptors for ORR previously proposed for MN4 complexes. As the active site is the Cu(I) center, the foot of the wave for O2 reduction on electrodes modified with Cu bisphenanthrolines appears at potentials very close to the [Cu(II)phen2]ad++ + e– ⇆ [Cu(I)phen2]ad+ redox process. Generally, the catalytic activity as (log i)E versus the ECu(II)/(I)° redox potentials follows a linear correlation with a slope close to +0.120 V/decade, where the activity increases as the ECu(II)/(I)° becomes more positive. This indicates that electron-withdrawing substituents on the ligand favor the reaction by shifting the ECu(II)/(I)° to more positive values, making the Cu center more noble. This shift in the ECu(II)/(I)° is essentially an electronic effect. However, another way to stabilize the Cu(I) state is by placing groups on the ligand that hinder the [Cu(II)square-planar]ad++/[Cu(I)tetrahedral]ad+ change. We have found that this steric effect seems to be more prominent than the electronic effects caused by electron-withdrawing groups and the increase in the catalytic activity for ORR is more pronounced.

Synthesis and characterization of self-assembled inorganic-organic hybrid arsenotungstates.

A series of 12 inorganic-organic hybrid 4f-substituted arsenotungstates decorated with 3d-based complexes along with acetate bridging, viz. {[Cu2(H2O)(1,10-phen)2(μ-CH3COO)2]4[Ln2(H2O)2(μ-CH3COO)2(α-AsW11O39)2]}2- (LnIII = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu), have been synthesized. These compounds were isolated using a one-pot synthetic strategy with copper, lanthanoid, trilacunary arsenotungstate and 1,10-phenanthroline as precursors. They were characterized using various analytical techniques, such as single-crystal X-ray diffraction (SC-XRD), powder XRD (PXRD), Fourier transform IR (FT-IR) spectroscopy, UV-Vis spectroscopy and thermogravimetric analysis (TGA). In all these compounds, a dinuclear Ln2(ac)2 moiety is sandwiched between two monolacunary [AsW11O39]7- polyoxometalates (POMs), where the Ln2(ac)2 moiety is comprised of two acetate ligands in a μ-κO,O':κO fashion. Moreover, the anion is decorated by a copper-phenanthroline-acetate complex through a terminal O atom of the polyanion.