Synthesis, structures and magnetic properties in 3d-electron-rich isostructural complexes based on chains with sole syn–anti carboxylate bridges

A tetracobalt(II) cluster with a two vertex truncated dicubane topology endogenously supported by carboxylate-based (2-pyridyl)methylamine ligands: magneto-structural and DFT studies

A reaction between CoCl2 and L3-(CO2-)2 (2 : 1 stoichiometry) in CH3OH affords a discrete complex [CoII4-{L3-(CO2-)2}2(μ3-OCH3)2(CH3OH)2(H2O)2Cl2] (1) [L3-(CO2-)2 = 3-[N-{2-(pyridin-2-yl)methyl}amino]-bis(propionate)]. The structure of 1 reveals two terminal mononuclear CoII{L3-(CO2-)2}Cl units connected by a dimeric CoII2(μ3-OCH3)2(CH3OH)2(H2O) unit present in the centre through two methoxo (μ3-OCH3)- and two carboxylate (μ-1,1-OCO-) bridges affording a tetranuclear coordination cluster of Co(II) with a defective dicubane topology. In 1, Co1 (terminal) has distorted octahedral CoIIN2O3Cl and the central Co2 has CoIIO6 coordination. Such coordination arrangements afford the observed topology. Variable-temperature magnetic studies reveal anti-ferromagnetic coupling in 1. Three magnetic exchange interactions (one anti-ferromagnetic and two ferromagnetic: J1 = +3.3 cm-1 (Co⋯Co 3.176 Å; μ-1,1-OCO- and μ3-OCH3 bridges), J2 = -2.5 cm-1 (Co⋯Co 3.228 Å; μ-1-OCO- and μ3-OCH3 bridges) and J3 = +10.6 cm-1 (Co⋯Co 3.084 Å; two μ3-OCH3 bridges)) have been identified, with the inclusion of the orbital reduction parameter (α = Aκ = 1.38), spin-orbit coupling (λ = -158 cm-1) and axial distortion (energy gap Δ = -975 cm-1 between singlet and doublet levels), rationalized by density functional theory (DFT) calculations.

Copper(II) coordination polymer based on l-arginine as a supramolecular hybrid inorganic–organic material: synthesis, structural, spectroscopic and magnetic properties

We report the synthesis and structural, spectroscopic and magnetic properties of new 1D coordination polymeric complex {[Cu(μ-l-Arg)2]SO4⋅1.5H2O}n (1) that contains asymmetric μ−O,O’ carboxylic bridge linking distorted square-pyramidal [Cu(μ-l-Arg)2]2+ coordination units. In 1D, the syn−anti−μ2−η1:η1zigzag polymer conformation, the adjacent Cu(II) ions are distanced by 5.707 Å, and the subsequent Cu∙∙∙Cu proximity in 1D-coordination chain equals 6.978 Å. Detailed interpretation of IR and Raman spectra of l-arginine and 1 was performed. The principal components of the g tensor determined from EPR experiments (gx = 2.059, gy = 2.075, gz = 2.228) indicate nearly axial symmetry of Cu(II) coordination sphere and correspond to the unpaired electron occupying the dx2–y2 orbital. The single broad band at 16,200 cm–1, characteristic of d−d transition, is assigned to the dominant dublet-dublet 2B1g(dx2–y2)→ 2Eg(dyz≈dxz) transition. Magnetic susceptibility measurements have revealed ferromagnetic coupling between the Cu(II) ions within the 1D-coordination chain, while the intermolecular coupling is antiferromagnetic.

Graphical Abstract

Metal ions impact on the isostructurality and properties of 2D coordination polymers

Two new 2,6-diacetylpyridine bis(nicotinoylhydrazone) coordination polymers with general formula {[MIIL]∙xsolvent}n, in which MII=Fe, Co, were prepared solvothermally and characterized by various methods. Both compounds exhibit isostructurality with different solvents with...

Structures and magnetic properties of two heterometallic Cu(ii)–Cd(ii) polymers exhibiting antiferromagnetic ordering

Two heterometallic Cu(ii)–Cd(ii) polymers (1 and 2) with a 2D layer or 1D chain structure were obtained and their magneto-structural correlations were discussed, and 1 displayed antiferromagnetic ordering at lower temperature.

Crystal structure, Hirshfeld surface analysis and DFT studies of tetra-kis-(μ-3-nitro-benzoato-κ2 O 1:O 1')bis-[(N,N-di-methyl-formamide-κO)copper(II)] di-methyl-formamide disolvate

The title compound, [Cu2(C7H4NO4)4(C3H7NO)2]·(C3H7NO)2, is a binuclear copper(II) complex located on an inversion center midway between the two copper(II) cations. The asymmetric unit consists of one CuII cation, two 3-nitro-benzoato ligands, and two di-methyl-formamide (DMF) mol-ecules, one of which coordinates to the CuII cation and one is a solvate mol-ecule. The carboxyl-ate groups of the ligands bridge two CuII cations with a Cu-Cu distance of 2.6554 (6) Å, completing a distorted octa-hedral O5Cu coordination environment. The dihedral angles between the carboxyl-ate and the aromatic ring planes of the two independent ligands are different from one another, viz. 5.2 (3) and 23.9 (3)°. The three-dimensional structure is consolidated by weak C-H⋯O inter-actions and stabilized by π-π stacking inter-actions between the aromatic rings. The complex and the free ligand were further characterized by Fourier-transform infrared spectroscopy (FT-IR), and the energies of the frontier mol-ecular orbitals of the complex were determined by DFT calculations at the B3LYP/def2-TZVP level of theory.

Dimeric Mn(ii), Co(ii), Ni(ii) and Cu(ii) complexes of a common carboxylate-appended (2-pyridyl)alkylamine ligand: structure, magnetism and DFT study

Weak anti- (1) and ferro-magnetic (2–4) interactions are observed in [MII2(L3)2(S)2]2+ (Mn 1, Co 2, Ni 3) (S = MeOH) and Cu 4 (S = none).

Two ZnII-based MOFs constructed with biphenyl-2,2',5,5'-tetracarboxylic acid and flexible N-donor ligands: syntheses, structures and properties

Two new Zn²⁺-based metal-organic frameworks (MOFs) based on biphenyl-2,2',5,5'-tetracarboxylic acid, i.e. H₄(o,m-bpta), and N-donor ligands, namely, poly[[(μ₄-biphenyl-2,2',5,5'-tetracarboxylato)bis{[1,3-phenylenebis(methylene)]bis(1H-imidazole)}dizinc(II)] dimethylformamide monosolvate dihydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·C₃H₇NO·2H₂O}_n or {[Zn₂(o,m-bpta)(1,3-bimb)₂]·C₃H₇NO·2H₂O}_n (1) {1,3-bimb = [1,3-phenylenebis(methylene)]bis(1H-imidazole)}, and poly[[(μ₄-biphenyl-2,2',5,5'-tetracarboxylato)bis{[1,4-phenylenebis(methylene)]bis(1H-imidazole)}dizinc(II)] monohydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·H₂O}_n or {[Zn₂(o,m-bpta)(1,4-bimb)₂]·H₂O}_n (2) {1,4-bimb = [1,4-phenylenebis(methylene)]bis(1H-imidazole)}, have been synthesized under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. Structurally, the (o,m-bpta)^4- ligands are fully deprotonated and combine with Zn²⁺ ions in μ₄-coordination modes. Complex 1 is a (3,4)-connected porous network with honeycomb-like [Zn₂(o,m-bpta)]_n sheets formed by 4-connected (o,m-bpta)^4- ligands. Complex 2 exhibits a (2,4)-connected network formed by 4-connected (o,m-bpta)^4- ligands linking Zn²⁺ ions in left-handed helical chains. The cis-configured 1,3-bimb and 1,4-bimb ligands bridge Zn²⁺ ions to form multi-membered [Zn₂(bimb)₂] loops. Optically, the complexes show strong fluorescence and display larger red shifts compared to free H₄(o,m-bpta). Complex 2 shows ferroelectric properties due to crystallizing in the C_2v polar point group.

Effects of two different solvents on the syntheses, structural diversity, and magnetic properties of six Mn(ii) complexes derived from 3,3′-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoate and variable N-donor ligands

Six Mn(ii) complexes of the 3,3′-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoate ligand in two different solvent systems with variable N-donor ligands were obtained and showed different structures and magnetic properties.

Two CoII coordination polymers of biphenyl-2,2',5,5'-tetracarboxylic acid with flexible N-donor ligands: syntheses, structures and magnetic properties

Two Co^II-based coordination polymers, namely poly[(μ₄-biphenyl-2,2',5,5'-tetracarboxylato){μ₂-1,3-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)], [Co₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]_n or [Co₂(o,m-bpta)(1,3-bimb)₂]_n (I), and poly[[aqua(μ₄-biphenyl-2,2',5,5'-tetracarboxylato){1,4-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)] dihydrate], {[Co₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂(H₂O)₂]·4H₂O}_n or {[Co₂(o,m-bpta)(1,4-bimb)₂(H₂O)₂]·4H₂O}_n (II), were synthesized from a mixture of biphenyl-2,2',5,5'-tetracarboxylic acid, i.e. [H₄(o,m-bpta)], CoCl₂·6H₂O and N-donor ligands under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. The bridging (o,m-bpta)^4- ligands combine with Co^II ions in different μ₄-coordination modes, leading to the formation of one-dimensional chains. The central Co^II atoms display tetrahedral [CoN₂O₂] and octahedral [CoN₂O₄] geometries in I and II, respectively. The bis[(1H-imidazol-1-yl)methyl]benzene (bimb) ligands adopt trans or cis conformations to connect Co^II ions, thus forming two three-dimensional (3D) networks. Complex I shows a (2,4)-connected 3D network with left- and right-handed helical chains constructed by (o,m-bpta)^4- ligands. Complex II is a (4,4)-connected 3D novel network with ribbon-like chains formed by (o,m-bpta)^4- linkers. Magnetic studies indicate an orbital contribution to the magnetic moment of I and II due to the longer Co...Co distances. An attempt has been made to fit the χ_MT results to the magnetic formulae for mononuclear Co^II complexes, the fitting indicating the presence of weak antiferromagnetic interactions between the Co^II ions.

Cadmium(II) three-dimensional coordination polymers constructed from 1,3,5-tris(4-carboxyphenoxy)benzene: synthesis, crystal structure, fluorescence and I2 sorption characterization

Two three-dimensional (3D) CdII coordination polymers, namely poly[[di-μ-aqua-diaquabis{μ5-4,4′,4′′-[benzene-1,3,5-triyltris(oxy)]tribenzoato}tricadmium(II)] dihydrate], {[Cd3(C27H15O9)2(H2O)4]·2H2O} n , (I), and poly[[aqua{μ6-4,4′,4′′-[benzene-1,3,5-triyltris(oxy)]tribenzoato}(μ-formato)[μ-1,1′-(1,4-phenylene)bis(1H-imidazole)]dicadmium(II)] dihydrate], {[Cd2(C27H15O9)(C12H10N4)(HCOO)(H2O)]·2H2O} n , (II), have been hydrothermally synthesized from the reaction system containing Cd(NO3)2·4H2O and the flexible tripodal ligand 1,3,5-tris(4-carboxyphenoxy)benzene (H3tcpb) via tuning of the auxiliary ligand. Both complexes have been characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR spectra, powder X-ray diffraction and thermogravimetric analysis. Complex (I) is a 3D framework constructed from trinuclear structural units and tcpb3− ligands in a μ5-coordination mode. The central CdII atom of the trinuclear unit is located on a crystallographic inversion centre and adopts an octahedral geometry. The metal atoms are bridged by four syn–syn carboxylate groups and two μ2-water molecules to form trinuclear [Cd3(COO)4(μ2-H2O)2] secondary building units (SBUs). These SBUs are incorporated into clusters by bridging carboxylate groups to produce pillars along the c axis. The one-dimensional inorganic pillars are connected by tcpb3− linkers in a μ5-coordination mode, thus forming a 3D network; its topology corresponds to the point symbol (42.62.82)(44.62)2(45.66.84)2. In contrast to (I), complex (II) is characterized by a 3D framework based on dinuclear cadmium SBUs, i.e. [Cd2(COO)3]. The two symmetry-independent CdII ions display different coordinated geometries, namely octahedral [CdN2O4] and monocapped octahedral [CdO7]. The dinuclear SBUs are incorporated into clusters by bridging formate groups to produce pillars along the c axis. These pillars are further bridged either by tcpb3− ligands into sheets or by 1,4-bis(imidazol-1-yl)benzene ligands into undulating layers, and finally these two-dimensional surfaces interweave, forming a 3D structure with the point symbol (4.62)(47.614). Compound (II) exhibits reversible I2 uptake of 56.8 mg g−1 with apparent changes in the visible colour and the UV–Vis and fluorescence spectra, and therefore may be regarded as a potential reagent for the capture and release of I2.

A novel 3D Cd(ii) coordination polymer generated via in situ ligand synthesis involving C-O ester bond formation

A novel 3D Cd(ii) coordination polymer {[Cd(ddpa)(2,2′-bpy)]·H₂O}_n (1) (H₂ddpa = 5,10-dioxo-5,10-dihydro-4,9-dioxapyrene-2,7-dicarboxylic acid, 2,2′-bpy = 2,2′-bipyridine) is hydrothermally synthesized in situ, and the influencing factors and mechanism for the in situ reaction are briefly discussed. The synthesis of 1 requires the formation of a new C–O ester bond. This current study confirms that metal ions and N-donor ligands play important roles in the domination of the in situ ligand from 6,6′-dinitro-2,2′,4,4′-biphenyltetracarboxylic acid (H₄dbta). Furthermore, the structure, thermal stability and photoluminescent property of 1 are also investigated.

A 3D Cd(ii) coordination polymer comprising ligand molecules not included in the original reaction mixtures but instead formed via in situ ligand synthesis involving a C–O ester bond.

Spectroscopy and DFT Calculations of Flavo-Diiron Nitric Oxide Reductase Identify Bridging Structures of NO-Coordinated Diiron Intermediates

Flavo-diiron proteins (FDPs) are widespread in anaerobic bacteria, archaea, and protozoa, where they serve as the terminal components of dioxygen and nitric oxide reductive scavenging pathways. FDPs contain an N,O-ligated diiron site adjacent to a flavin mononucleotide (FMN) cofactor. The diiron site is structurally similar to those in hemerythrin, ribonucleotide reductase, and methane monooxygenase. However, only FDPs turn over NO to N2O at significant rates and yields. Previous studies revealed sequential binding of two NO molecules to the diferrous site, forming mono- and dinitrosyl intermediates leading to N2O formation. In the present work, these mono- and dinitrosyl intermediates have been characterized by EPR and Mössbauer spectroscopies and DFT calculations. Our results show that the iron proximal to the cofactor binds the first NO to form the diiron mononitrosyl complex, implying the iron distal to the FMN binds the second NO to form the diiron dinitrosyl intermediate. The exchange-coupling constants, J (H = JS1·S2), were found to differ substantially, +17 cm-1 for the diiron mononitrosyl and +60 cm-1 for the diiron dinitrosyl. Notwithstanding this large difference, our findings indicate retention of at least one hydroxo bridge throughout the NOR catalytic cycle. The Mossbauer hyperfine parameters and DFT calculations confirmed a semibridging NO- ligand in the mononitrosyl intermediate that lowers the exchange parameter. The DFT calculations on the dinitrosyl intermediate suggest a contribution to J from direct exchange between the S = 1 spins on the NO- ligands, which could initiate N-N bond formation. Our results provide insight into why FDPs are the only known nonheme diiron enzymes that competently turn over NO to N2O.

A thermally stable three-dimensional cobalt(II) coordination polymer based on the V-shaped ligand 4-(4-carboxyphenoxy)isophthalate

A new cobalt(II) coordination polymer (CP), poly[[bis[μ6-4-(4-carboxylatophenoxy)benzene-1,3-dicarboxylato-κ6 O 1:O 1:O 3:O 3′:O 4:O 4′]bis(1,10-phenanthroline-κ2 N,N′)tricobalt(II)] 0.72-hydrate], {[Co3(C15H7O7)2(C12H8N2)2]·0.72H2O} n , (I), is constructed from CoII ions and 4-(4-carboxyphenoxy)isophthalate (cpoia3−) and 1,10-phenanthroline (phen) ligands. Based on centrosymmetric trinuclear [Co3(phen)2(COO)6] secondary building units (SBUs), the structure of (I) is a three-dimensional CP with a (3,6)-connected net and point symbol (42.6)2(44.62.87.102). The positions of four [Co3(phen)2(COO)6] SBUs and four cpoia3− ligands reproduce a Chinese-knot-shaped arrangement along the ab plane. (I) has been characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction (PXRD) and thermostability analysis. It shows a good thermal stability from room temperature to 673 K. In addition, the temperature dependence of the magnetic properties was measured.

Crystal structure of tetra-kis-[μ-2-(meth-oxy-carbon-yl)benzoato-κ2O1:O1']bis-[(N,N-di-methyl-formamide-κO)copper(II)](Cu-Cu) di-methyl-formamide disolvate

The title compound, [Cu2(C9H7O4)4(C3H7NO)2]·2C3H7NO, crystallizes in the monoclinic P21/c space group, with the binuclear copper unit occupying a special position on an inversion center, i.e. the asymmetric unit of the crystal consists of one CuII ion, two 2-(meth-oxy-carbon-yl)benzoate ligands, and two DMF mol-ecules (one coordinated and one solvate). The binuclear complex displays a paddle-wheel-shaped structure with the two copper atoms being in a Jahn-Teller-distorted octa-hedral coordination environment. Each 2-(meth-oxy-carbon-yl)benzoate substituent acts as a bridging ligand and links two Cu atoms with a Cu-Cu distance of 2.633 (1) Å. The carboxyl-ate groups of the 2-(meth-oxy-carbon-yl)benzoate ligands adopt bidentate syn-syn bridging modes, with dihedral angles between the carboxyl-ate planes and the aromatic rings of 18.427 (4) and 43.029 (6)°. In the crystal, adjacent DMF mol-ecules coordinated to copper atoms are arranged in a mutual 'head-to-tail' manner by offset face-to-face π-π stacking inter-actions, resulting in chains along the c-axis direction. The planes of the coordinated DMF mol-ecules are parallel to each other, the distance between them being 3.33 (1) Å. A three-dimensional structure is assembled from the chains by weak C-H⋯O and C-H⋯π inter-molecular inter-actions involving the DMF solvent mol-ecules. One of the methyl ester groups is disordered over two sites with an occupancy ratio of 0.751 (12):0.249 (12).

Binuclear Mn2+ complexes of a biphenyltetracarboxylic acid with variable N-donor ligands: syntheses, structures, and magnetic properties

A series of manganese(ii) coordination polymers show a variety of features due to the recognition and assembly processes of the N-donor ligands.

Exploring the syntheses, structures, topologies, luminescence sensing and magnetism of Zn(ii) and Mn(ii) coordination polymers based on a semirigid tricarboxylate ligand

Two Zn(ii)-CPs and two Mn(ii)-CPs were constructed from metal salts, H₃cpota and N-heterocyclic group ligands. Their structures, magnetic properties and luminescence sensing properties have been studied in detail.

A three-dimensional ZnII coordination polymer constructed from 1,1'-biphenyl-2,2',4,4'-tetracarboxylate and 1,4-bis(1H-imidazol-1-yl)benzene ligands exhibiting photoluminescence

Ligands based on polycarboxylic acids are excellent building blocks for the construction of coordination polymers; they may bind to a variety of metal ions and form clusters, as well as extended chain or network structures. Among these building blocks, biphenyltetracarboxylic acids (H₄bpta) with C₂ symmetry have recently attracted attention because of their variable bridging and multidentate chelating modes. The new luminescent three-dimensional coordination polymer poly[(μ₅-1,1'-biphenyl-2,2',4,4'-tetracarboxylato)bis[μ₂-1,4-bis(1H-imidazol-1-yl)benzene]dizinc(II)], [Zn₂(C₁₆H₆O₈)(C₁₂H₁₀N₄)]_n, was synthesized solvothermally and characterized by single-crystal X-ray diffraction, elemental analysis and IR spectroscopy. The crystal structure contains two crystallographically independent Zn^II cations. Both metal cations are located on twofold axes and display distorted tetrahedral coordination geometries. Neighbouring Zn^II centres are bridged by carboxylate groups in the syn-anti mode to form one-dimensional chains. Adjacent chains are linked through 1,1'-biphenyl-2,2',4,4'-tetracarboxylate and 1,4-bis(1H-imidazol-1-yl)benzene ligands to form a three-dimensional network. In the solid state, the compound exhibits blue photoluminescence and represents a promising candidate for a thermally stable and solvent-resistant blue fluorescent material.

Syntheses, structures, and magnetic properties of two unique Cu(ii)-based coordination polymers involving a crystal-to-crystal structural transformation from a 1D chain to a 3D network

Promoted by the DMF solvent, the 1D chain structure of 1 can be irreversibly transformed into the 3D sod network structure of 2 in a crystal-to-crystal fashion, which is accompanied by a drastic magnetic change.

A two-dimensional mixed-valence Cu(II)/Cu(I) coordination polymer constructed from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate

Coordination polymers are a thriving class of functional solid-state materials and there have been noticeable efforts and progress toward designing periodic functional structures with desired geometrical attributes and chemical properties for targeted applications. Self-assembly of metal ions and organic ligands is one of the most efficient and widely utilized methods for the construction of CPs under hydro(solvo)thermal conditions. 2-(Pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate (HPIDC(2-)) has been proven to be an excellent multidentate ligand due to its multiple deprotonation and coordination modes. Crystals of poly[aquabis[μ3-5-carboxy-2-(pyridin-3-yl)-1H-imidazole-4-carboxylato-κ(5)N(1),O(5):N(3),O(4):N(2)]copper(II)dicopper(I)], [Cu(II)Cu(I)2(C10H5N3O4)2(H2O)]n, (I), were obtained from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylic acid (H3PIDC) and copper(II) chloride under hydrothermal conditions. The asymmetric unit consists of one independent Cu(II) ion, two Cu(I) ions, two HPIDC(2-) ligands and one coordinated water molecule. The Cu(II) centre displays a square-pyramidal geometry (CuN2O3), with two N,O-chelating HPIDC(2-) ligands occupying the basal plane in a trans geometry and one O atom from a coordinated water molecule in the axial position. The Cu(I) atoms adopt three-coordinated Y-shaped coordinations. In each [CuN2O] unit, deprotonated HPIDC(2-) acts as an N,O-chelating ligand, and a symmetry-equivalent HPIDC(2-) ligand acts as an N-atom donor via the pyridine group. The HPIDC(2-) ligands in the polymer serve as T-shaped 3-connectors and adopt a μ3-κ(2)N,O:κ(2)N',O':κN''-coordination mode, linking one Cu(II) and two Cu(I) cations. The Cu cations are arranged in one-dimensional -Cu1-Cu2-Cu3- chains along the [001] direction. Further crosslinking of these chains by HPIDC(2-) ligands along the b axis in a -Cu2-HPIDC(2-)-Cu3-HPIDC(2-)-Cu1- sequence results in a two-dimensional polymer in the (100) plane. The resulting (2,3)-connected net has a (12(3))2(12)3 topology. Powder X-ray diffraction confirmed the phase purity for (I), and susceptibilty measurements indicated a very weak ferromagnetic behaviour. A thermogravimetric analysis shows the loss of the apical aqua ligand before decomposition of the title compound.

Construction of magnet-type coordination polymers using high-spin {Ni4}-citrate cubane as secondary building units

A robust ferromagnetic secondary building unit based on {Ni₄}-citrate cubane is identified to be able to construct diverse structures while retaining the original magnetism.

A new family of 1D, 2D and 3D frameworks aggregated from Ni5, Ni4 and Ni7 building units: synthesis, structure, and magnetism

Three polynuclear nickel(ii) complexes with 1D, 2D and 3D structures are controlled by carboxylate bridges of biphenyl-3,4′,5-tricarboxylic acid. Magnetic studies reveal that the polymers have ferromagnetic coupling features for 1 and 2 and an alternating magnetic chain behavior for 3.

Long-range antiferromagnetic order in malonate-based compounds Na2M(H2C3O4)2·2H2O (M = Mn, Fe, Co, Ni)

Newly synthetized metal malonates of formulae Na₂M(H₂C₃O₄)₂·2H₂O (M = Mn, Fe, Co, Ni) exhibit distinct long-range antiferromagnetic orders despite their similar structure and chemistry.

Oxalate-mediated long-range antiferromagnetism order in Fe2(C2O4)3·4H2O

Neutron powder diffraction and susceptibility measurements reveal the long range antiferromagnetic order mediated by oxalate molecules in Fe₂(C₂O₄)₃·4H₂O.