Heterometallic Coordination Polymers Research Articles

A spin-crossover phenomenon in a 2D heterometallic coordination polymer with [Pd(SCN)4]2- building blocks.

Two new two-dimensional (2D) coordination polymers, [FeII(L)2{PdII(SCN)4}] (L1 = 3-(9-anthracenyl)-pyridine (1) and L2 = 4-(9-anthracenyl)-pyridine (2)), were constructed by employing square-planar [Pd(SCN)4]2- building blocks. Compound 1 exhibits a complete spin-crossover (SCO) behaviour under normal atmospheric pressure, and represents the first SCO example in a 2D system containing [Pd(SCN)4]2- units. In contrast, compound 2 only shows paramagnetic behaviour at measured temperatures. It is clear that the fine-tuning of the monodentate ligand can modulate the ligand field and packing fashions, which sheds light on developing new SCO materials.

Luminescent 1D heterometallic (Ir,Cd) coordination polymers based on bis-cyclometalated Ir(III) metallatectons and trinuclear Cd(II) dianionic nodes.

Seven isostructural heterometallic luminescent (Ir,Cd) coordination polymers were prepared upon the combination of tris-chelate cationic Ir(III) complexes behaving as metalloligands with Cd(II) salts. Three octahedral Ir(III) complexes have been considered in the present report. They consist of a bipyridine unit functionalised with 3-pyridyl moieties as peripheral coordinating sites and two 2-phenylpyridyl cyclometalating derivatives. Three cadmium halide salts CdX2 (X = Cl, Br, I) were used and rearranged themselves during the self-assembly process with the metallatectons to afford a dianonic trinuclear Cd node [Cd3X8]2-. Seven out of the nine possible metallotecton-metal salt combinations could be characterised in the crystalline phase by X-ray diffraction on single crystals proving the isostructurality of the seven extended architectures studied. All of the CPs are luminescent with small shifts observed in the emission wavelength compared to the discrete complexes. Depending on the degree of fluorination of the two cyclometalating units, tuning of the emission wavelength of the discrete complexes as well as of the resulting coordination polymers is achieved.

Synthesis, Crystal Structure and Luminescent Properties of a 3D Mg(II)−Sm(III) Heterometallic Coordination Polymer Containing 20‐member Water Clusters

AbstractA new Mg(II)−Sm(III) heterometallic coordination polymer (Cp) with the formula [Sm2(pydc)6Mg3(H2O)6] ⋅ 11H2O (1) (H2pydc=pyridine‐2,6‐dicarbolylic acid) has been solvothermal synthesized by reacting pyridine‐2,6‐dicarbolylic acid, Sm(NO3)3 ⋅ 6H2O, MgCl2 ⋅ 6H2O and imidazole at 393 K for 48 h. It was characterized by single‐crystal X‐ray diffraction, elemental analysis, IR and TGA. The results show that coordination polymer 1 exhibits a three‐dimensional network structure and crystallizes in hexagonal crystal system, space group P6/mcc, with crystallographic data of a=15.4203(6) Å, b=15.4203(6) Å, c=15.2563(6) Å, α=β=90°, γ=120°, V=3141.7(3) Å3, and Z=2. The twenty‐member water cluster structure and topological structure of compound 1 were analyzed, and its luminescent properties were studied. It presents the characteristic emission spectra of Sm(III) ions.

Magnetic and Electrical Behaviors of the Homo- and Heterometallic 1D and 3D Coordination Polymers Based on the Partial Decomposition of the [Cr(C2O4)3]3− Building Block

One-dimensional (1D) oxalate-bridged homometallic {[Mn(bpy)(C2O4)]·1.5H2O}n (1) (bpy = 2,2’-bipyridine) and heterodimetallic {[CrCu3(bpy)3(CH3OH)(H2O)(C2O4)4][Cu(bpy)Cr(C2O4)3]·CH2Cl2·CH3OH·H2O}n (2) coordination polymers, as well as the three-dimensional (3D) heterotrimetallic {[CaCr2Cu2(phen)4(C2O4)6]·4CH3CN·2H2O}n (3) (1,10-phenanthroline) network, have been synthesized by a building block approach using a layering technique, and characterized by single-crystal X-ray diffraction, infrared (IR) and impedance spectroscopies and magnetization measurements. During the crystallization process partial decomposition of the tris(oxalato)chromate(III) happened and 1D polymers 1 and 2 were formed. The antiferromagnetic interactions between the manganese(II) ions were mediated by oxalate ligands in the chain [Mn(bpy)(C2O4)]n of 1, with intra-chain super-exchange interaction 𝐽 = (−3.134 ± 0.004) K; magnetic interaction between neighbouring chains is negligible making this system closer than other known Mn-chains to the ideal 1D Heisenberg antiferromagnet. Compound 2 comprises a 1D coordination anion [Cu(bpy)Cr(C2O4)3]nn− (Cr2–Cu4) with alternating [Cr(C2O4)3]3− and [Cu(bpy)]2+ units mutually bridged through the oxalate group. Another chain (Cr1–Cu3) is similar, but involves a homodinuclear unit [Cu(bpy)(H2O)(µ-C2O4)Cu(bpy)(CH3OH)]2+ (Cu1–Cu2) coordinated as a pendant group to a terminal oxalate oxygen. Magnetic measurements showed that the Cu1−Cu2 cationic unit is a strongly coupled antiferromagnetic dimer, independent from the other magnetic ions within ferromagnetic chains Cr1–Cu3 and Cr2–Cu4. A 3D polymer {[CaCr2Cu2(phen)4(C2O4)6]·4CH3CN·2H2O}n (3) comprising three different metal centers (Ca2+, Cr3+ and Cu2+) oxalate-bridged, contains Ca2+ atoms as nodes connected with four Cr3+ atoms through oxalate ligands. The network thus formed can be reduced to an underlying graph of diamondoid (dia) or (66) topology. Magnetization of 3 shows the ferromagnetic oxalate-bridged dimers [CuIICrIII], whose mutual interaction could possibly originate through the spin polarization of Ca2+ orbitals. Compounds 1 and 3 exhibit lower electrical conductivity at room temperature (RT) in comparison to compound 2.

RETRACTED ARTICLE: Synthesis and anti-breast cancer activity on osteogenic sarcoma of a in/Na heterometallic coordination polymer

We, the Editors and Publisher of the journal Inorganic and Nano-Metal Chemistry, have retracted the following article: Ying Liu, Peng Mao, Yu Wu, Guo-Feng Ma, Wen Xue & Wei-Dong Tang. Synthesis and anti-breast cancer activity on osteogenic sarcoma of a in/Na heterometallic coordination polymer, Inorganic and Nano-Metal Chemistry. 2021; VOL. 51, NO. 11, 1492–1498. DOI: 10.1080/24701556.2020.1841233. Since publication, concerns have been raised about the integrity of the data in the article. When approached for an explanation, the authors have been unable to address the concerns raised and have not been able to provide sufficient supporting information. As verifying the validity of published work is core to the integrity of the scholarly record, we are therefore retracting the article. The corresponding author listed in this publication has been informed. The authors do not agree with the retraction. We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.

Synthesis, structures and luminescence properties of three Mg(II)-Dy(III) heterometallic coordination polymers

Three new heterometallic coordination polymers [Dy2(pydc)6Mg3(H2O)6]·11H2O (1), [Dy(pydc)3][Mg(H2O)6]·Him·7H2O (2), and [Dy(pydc)3(im)2Mg(H2O)2]·Him·3H2O (3) (H2pydc = pyridine-2,6-dicarbolylic acid, im = imidazole) were solvothermally synthesized by reacting H2pydc, Dy(NO3)3·6H2O, MgCl2·6H2O and imidazole at 393 K for 48 h. They were characterized by elemental analysis, IR, TG and XRD. The three compounds are different in structure. Coordination polymer 1 exhibits a three-dimensional network structure with topology symbol of {44.62}3{49.66}2. Complex 2 is a zero-dimensional ionic complex. Coordination polymer 3 displays a one-dimensional chain structure. The solid-state luminescence properties for 1–3 were determined. They all show characteristic emission spectra of Dy(III) ions.

0D to 3D PrIII metal-organic networks crystal engineered for optimal iodine adsorption.

Four new praseodymium(III) metal-organic compounds varying in dimensionality from 0D to 3D have been designed and synthesized based on N-heterocyclic polycarboxylic acids, including pyridine-2,6-dicarboxylic acid (H2pydc) and pyrazine-2,3-dicarboxylic acid (H2pzdc). Altering the concentration of piperazine (pip, ancillary ligand) enables control over the dimensionality of the compound by switching between the 0D [H2pip][Hpip][Pr(pydc)3]·4H2O (I) and the 1D {[Pr(pydc)(Hpydc)(H2O)2]·4H2O}n (II) coordination polymer (CP). Upon replacing H2pydc with H2pzdc, CP II is converted to the 2D CP [Pr(pzdc)(Hpzdc)(H2O)3]n (III) and using the metalloligand [Zn(Hpzdc)2(H2O)2]2-, the 3D heterometallic CP {[Pr2Zn(pzdc)4(H2O)6]·2H2O}n (IV) is formed. Compound IV shows high stability in the absence of uncoordinated solvent molecules and is stable up to 400°C, even in the presence of humidity. Therefore, IV was utilized for iodine adsorption in the vapour phase and in the presence of humidity. The results confirm the remarkable potential of IV for reversible adsorption of iodine vapour.

Temperature-induced solvent assisted single-crystal-to-single-crystal transformation of Mg(II)-Ln(III) heterometallic coordination polymers

Two new heterometallic coordination polymers (CPs) [Ln2 (pydc)6Mg3(H2O)6]·11H2O (Ln ​= ​Eu (1), Tb (2); H2pydc ​= ​pyridine-2,6-dicarbolylic acid) were synthesized by solvothermal method at 120 ​°C in 48 ​h. Interestingly, after being left in the mother liquor for 3 days at room temperature, the crystal structures of the coordination polymers transform into anionic complexes 2 [Mg(H2O)6]·2 [Ln (pydc)3]·2Him·im•8H2O (Ln ​= ​Eu (3), Tb (4); im ​= ​imidazole; Him ​= ​protonated imidazole) by single-crystal-to-single-crystal transformation. The four complexes were characterized by elemental analysis, IR, TG, XRD as well as single-crystal X-ray diffraction. Coordination polymers 1 and 2 exhibit three-dimensional network structure and their topology symbol is {44.62}3{49.66}2, whereas complexes 3 and 4 are zero dimensional molecules. The luminescence properties of the complexes were determined at solid state. They show characteristic emission spectra of Eu(III) and Tb(III) ions, respectively. The quantum yield Фtotal is 48.42 ​± ​10%, 95.65 ​± ​10%, 44.22 ​± ​10%, and 76.97 ​± ​10% for coordination polymers 1 (Mg–Eu), 2 (Mg–Tb), 3 (Mg–Eu), and 4 (Mg–Tb), respectively. The corresponding fluorescence decay lifetime of 1–4 is τobs1 ​= ​1884.72 ​± ​1.51, 1777.75 ​± ​1.45, 1625.17 ​± ​1.40, and 1487.75 ​± ​1.36 ​μs? The effect of Mg(II) on the fluorescence properties of the lanthanide coordination polymers was investigated.

RETRACTED ARTICLE: Heterometallic La(III)-Co(II) coordination polymers: treatment activity on diabetic foot by reducing the TLR-4–NF-κB signaling pathway activation in the plantar tissue

Two new heterometallic coordination polymers (CPs) formulated as [LaCoCl(2,5-pydc)2(H2O)4]Cl (1, 2,5-H2pydc = pyridine-2,5-dicarboxylic acid) and [LaCoCl2(5,5 = pyridin3)(H2O)] (2, 5,5′-H2bpdc = 2,2ridine-2,5-dicar-dicarboxylic acid) have been solvothermally synthesized on the basis of the coordination between rare earth/transition metal ions and pyridinedicarboxylic acids. Their treatment activity on diabetic foot (DF) was evaluated in biological research. First of all, the content of the inflammatory cytokines in the plantar tissue was measured with the ELISA detection kit. Next, the real-time RT-PCR was performed for the measurement of the TLR-4–NF-κB signaling pathway activation.

Heterometallic coordination polymers: Treatment activity on diabetic foot by reducing the excess inflammatory response in the plantar tissue

Two new heterometallic coordination polymers formulated as {[LaCo(2.5-pydc)2(H2O)4]Cl·4H2O}n (1, 2,5-H2pydc = pyridine-2,5-dicarboxylic acid) and {[LaCo2Cl3(4,4′-bpdc)2(H2O)3]·H2O}n (2, 4,4′-H2bpdc = 2,2′-bipyridyl-4,4′-dicarboxylic acid) have been solvothermally synthesized using the coordination between rare earth/transition metal ions and pyridinedicarboxylic acids. To develop new candidates for enhancing the therapeutic effect of improved negative pressure suction for diabetic foot, the activities of compounds 1 and 2 were studied. First, the ELISA (enzyme linked immunosorbent assay) detection kit was used and the inflammatory cytokines in the plantar tissue were measured. Besides, the TLR-4-NF-κB signaling pathway was measured with real-time reverse transcription-polymerase chain reaction.

The formation and structure of the heterometallic coordination polymer in the system GeO2–xylaric, oxalic acids–CuCl2–2,2'-bipyridine–H2O/C2H5OH

The formation and structure of the heterometallic coordination polymer in the system GeO2–xylaric, oxalic acids–CuCl2–2,2'-bipyridine–H2O/C2H5OH

RETRACTED ARTICLE: Synthesis, Crystal Structure, and Anti-Gastric Cancer Activity of a Heterometallic Coordination Polymer Based on Flexible 6,6-Dithiodinicotinic Acid

A new bimetallic coordination polymer [In2Na(H2O)2(ddca)3](NO3)·4H2O (1, H2ddca = 6,6′-dithiodinicotinic acid) is produced via a hydrothermal reaction of In(NO3)3, H2ddca with NaOH as the pH modulator. Various characterization methods, such as thermogravimetric analysis (TGA), elemental analysis (EA), single crystal and powder X-ray diffraction measurements, are used. Furthermore, a process of sonochemistry with oleic acid at 453 K is used to produce nanoparticles of 1 (nano-1). In terms of the biological function of the synthesized complex, the real-time reverse transcription-polymerase chain reaction is carried out to explore the relative mRNA expression of miR-181 in MGC-803, BGC-823, and SGC-7901 gastric cancer cell lines, and the western blot is used to explore the protein expression of apoptotic protein Bcl-2.

Water Stable Heterometallic Zn-Tb Coordination Polymer for Rapid Detection of the Ultraviolet Filter Benzophenone.

Benzophenone (BP) is an ultraviolet filter (UVF) widely used in personal care products such as sunscreens and cosmetics. Excessive exposure to BP-type UVFs is a potential threat to human's health because of their endocrine-disrupting activity. Water stability of lanthanide compounds is crucial when they serve as luminescent sensors because of the practicality and recyclability. In this study, a water-stable luminescent Zn-Tb heterometallic coordination polymer was rationally designed and synthesized for rapid detection of BP. This material showed a high quenching effect, excellent selectivity, and fast response toward BP.

Heterometallic Cluster Coordination Polymers Assembled from Cuprous-Halide Clusters and Organotin–Oxygen Pyridinecarboxylate Clusters

By using bifunctional ligands bearing carboxylate and N-donor groups, the precursor of nBu2SnO undergoes a transformation to yield organotin–oxygen carboxylate clusters, namely, [(nBu2Sn)4(μ3-O)2(μ...

A Series Three-Dimensional Ln4Cr4 (Ln = Gd, Tb, Er) Heterometallic Cluster-Based Coordination Polymers Containing Interesting Nanotubes Exhibiting High Magnetic Entropy.

A series of novel 3D 3d-4f heterometallic cluster-based coordination polymers, [Ln4Cr4(μ3-O)4(μ4-O)4(NA)8(H2O)12]·xH2O (Ln = 1-Gd, 2-Tb, 3-Er; HNA = nicotinic acid; x = 13 (1-Gd), 11.33 (2-Tb), 15 (3-Er)), have been successfully synthesized by hydrothermal method using nicotinic acid as bridging ligand. The single-crystal X-ray diffraction (SCXRD) analysis indicated that the basic unit of Ln4Cr4 shows a butterfly-shaped structure. Furthermore, each Ln4Cr4 cluster connects with other four Ln4Cr4 clusters by bridging NA- ligands to form a 3D structure containing interesting 1D honeycomb-shaped coordination nanotubes. The variable temperature magnetic susceptibility measurements of compound 1 revealed that the existence of antiferromagnetic (AF) coupling between the metal ions in the Gd4Cr4 clusters. Field-dependent isothermal magnetization studies displayed that the magnetic entropy change (-ΔSm) value of 1-Gd reached 22.05 J K-1 kg-1.

A new approach to prepare the Mn(II)-based magnetic refrigerant through incorporating diamagnetic Cd(II) ion

One one-dimensional Cd(II)-Mn(II) heterometallic coordination polymer with 2-methylenesuccinate (MSA2−), [CdMn(MSA)2(H2O)5]·3H2O (1), has been successfully prepared and characterized. Single crystal X-ray diffraction analysis reveals that 1 crystallizes in monoclinic P21/c space group and has a 1D chain structure. The introduction of diamagnetic Cd(II) ion helps separate the neighboring Mn(II) ions well to prevent the strong Mn(II)-Mn(II) antiferromagnetic interaction. Magnetic studies show that 1 has a great cryogenic magnetocaloric effect with the maximum − ΔSm value of 21.93 J K−1 kg−1 at 2 K and ΔH = 7 T. This is the first example for Cd(II)-Mn(II) based molecule magnetic refrigerant.

Photophysical studies of coordination polymers and composites based on heterometallic lanthanide succinate

This work reports the synthesis and characterization of heterometallic Tb/Eu lanthanide-succinate coordination polymers (CPs) under hydrothermal conditions. Compounds were obtained inserting different quantities of Eu3+ ions into the terbium succinate structure, named here xEuyTbSuc (x and y are the percentage of the respective lanthanide ions). Composites with these heterometallic CPs and activated carbon (CP@AC, AC = activated carbon) were obtained using one-pot hydrothermal reactions. Bimetallic CPs with or without presence of AC crystallize in monoclinic system, isostructural to [Ln2(Suc)3(H2O)2]•0.5H2O (Ln = Eu or Tb), already described in the literature, confirmed by X-ray powder diffraction (XRPD) data. Scanning electron microscopy (SEM) images show the CP crystals inside the carbon pores. Luminescence spectroscopy measurements (excitation, emission and lifetime) were conducted to explore photophysical properties of these new materials. Lifetime data indicates all Eu3+ ions are in the same chemical environment. Even at low concentration (1%), Eu3+ transitions (5D0→7FJ (J = 0–4)) were observed in the emission spectrum, along transitions related to the Tb3+ cations (5D4→7FJ (J = 6–3)), due to the metal-to-metal charge transfer (MMCT) between the lanthanide ions. Similar results are found in the composites. Increasing the Eu3+ concentration, a more intense MMCT process took place, suppressing the terbium emission.

Two types of three-dimensional copper-lanthanide pyridine-2,3-dicarboxylate coordination polymers from one-pot reaction

Two types of copper-lanthanide heterometallic coordination polymers (CPs) [Ln2Cu3(2,3-pydc)6(H2O)6]·xH2O [Ln = La (1, x = 8), Nd (3, x = 10), 2,3-H2pydc = pyridine-2,3-dicarboxylic acid] and [Ln2Cu2(2,3-pydc)4(NO3)(OH)(H2O)6]·2H2O [Ln = La (2), Nd (4)] were successfully synthesized by one-pot reaction under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction. CPs 1–4 exhibit two kinds of three-dimensional (3D) structures with different topologies. In 1 and 3, the Cu(2,3-pydc)2 and Ln2(COO)4 units link each other to form a two-dimensional (2D) layer, and the adjacent 2D layers are extended by the Cu(2,3-pydc)4 units into a 3D framework with one-dimensional (1D) channels. In 2 and 4, the LnIII ions bridge the 1D chains based on 2,3-pydc and CuII into a 2D layer, and the nitrate and hydroxyl anions connect the adjacent 2D layers to generate a 3D framework with 1D channels. The electrochemical properties of 1–4 were studied.

Voltammetric Detection of 3-Nitropropionic Acid in Sugarcane Juices Using a Poly(L-citrulline)/Lanthanide-Containing Cyano-Bridged Heterometallic Coordination Polymer Modified Electrode

In this study, a novel poly(L-citrulline)/lanthanide-containing cyano-bridged heterometallic coordination polymer modified glassy carbon electrode, poly(L-Cit)/(Ho(III)-Fe(III)-WO42− CyHMCP/GCE, was constructed as a sensing platform for the electrochemical detection of 3-nitropropionic acid (3-NPA) using the two-step electrosynthesis method. The surface morphology of materials coated on the chemically modified electrode was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on the excellent synergistic electrocatalytic performance for electrochemical reduction of 3-NPA, the voltammetric detection of 3-NPA in real sugarcane juice samples was achieved with a facile sample pretreatment process and less matrix interference. Furthermore, by means of water-phase infrared spectra technique, the electrocatalytic reduction pathway of 3-NPA was preliminarily studied. Under the optimized detection conditions, a good linear relationship was obtained between the reduction peak current of 3-NPA and testing concentration in the range of 40.0–4.00 × 103 μM, with a regression equation of Ip (μA) = −3.126 + 0.08804C3-NPA (μM), R2 = 0.9997. The lower detection limit (LOD) of 3-NPA was estimated to be 16.0 μM (S/N = 3). Therefore, the method had been employed to analyze raw sugarcane samples, with the average recovery of 96.8%–104%, and the actual concentration level of free 3-NPA in the raw sugarcane juices was revealed.

Heterometallic coordination polymers based on homo- and heteroleptic Au(iii) dithiolene complexes

Two novel hetero- and homoleptic Au(iii) dithiolene complexes have been designed, synthesized, characterized and employed for the elaboration of heterometallic coordination networks.