Hydro(solvo)thermal synthetic strategy towards azido/formato-mediated molecular magnetic materials

A cyanometallate- and carbonate-bridged dysprosium chain complex with a pentadentate macrocyclic ligand: synthesis, structure, and magnetism

A novel one-dimensional polymeric cyanometallate- and carbonate-bridged dysprosium(iii) chain with a pentadentate macrocyclic ligand exhibits field-induced multiple-relaxation processes.

Quest for Extended Coordination Networks from High Connected Azido-Bridged Clusters

Two nets {[Co6(L)6(µ-1,1,1-N3)6]·H2O}n (1) and {[Co4(L)4(µ-1,1,1,1-N3)(µ-1,1-N3)2]·H+·5H2O}n (2) based on high connected µ-1,1,1 and µ-1,1,1 azido-bridged clusters were obtained with nicotinate N-oxide(L) as co-ligand. Magnetic interactions existed in 1 and 2,...

Metal hydrogen-bonded organic frameworks: structure and performance

Although great progress has been made in the design, synthesis, and performance expansion of porous materials, new porous materials with stable structures still need to be explored further. In recent years, porous molecular crystals formed by intermolecular interactions have attracted wide attention from chemists, especially metal hydrogen-bonded organic frameworks (M-HOFs) formed by connecting metal complexes through hydrogen bonds. Metal complexes with specific properties (e.g., magnetism, luminescence, sensing, and catalysis) can expand and develop the application of M-HOFs further. However, the huge volume, irregular shape, complex coordination modes, and interference of coordination bonds pose certain challenges in the synthesis and performance expansion of M-HOFs. In this frontier, we summarize the latest progress in the use of 3d, 4d, and 4f metal complexes for the synthesis of M-HOFs, and briefly introduce the performance expansion of these M-HOFs, which is expected to help expand new porous materials with stable structures and specific functions.

Synthesis, crystal structures and magnetic and electrochemiluminescence properties of three manganese(II) complexes

Three novel complexes, namely, penta-μ-acetato-bis(μ2-2-{[2-(6-chloropyridin-2-yl)hydrazinylidene]methyl}-6-methoxyphenolato)-μ-formato-tetramanganese(II), [Mn4(C13H11ClN3O2)2(C2H3O2)5.168(CHO2)0.832], 1, hexa-μ2-acetato-bis(μ2-2-{[2-(6-bromopyridin-2-yl)hydrazinylidene]methyl}-6-methoxyphenolato)tetramanganese(II), [Mn4(C13H11BrN3O2)2(C2H3O2)6], 2, and catena-poly[[μ2-acetato-acetatoaqua(μ2-2-{[2-(6-chloropyridin-2-yl)hydrazinylidene]methyl}-6-methoxyphenolato)dimanganese(II)]-μ2-acetato], [Mn2(C13H11ClN3O2)(C2H3O2)3(H2O)] n , 3, have been synthesized using solvothermal methods. Complexes 1–3 were characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. Complexes 1 and 2 are tetranuclear manganese clusters, while complex 3 has a one-dimensional network based on tetranuclear Mn4(L 1)2(CH3COO)6(H2O)2 building units (L 1 is 2-{[2-(6-chloropyridin-2-yl)hydrazinylidene]methyl}-6-methoxyphenolate). Magnetic studies reveal that complexes 1–3 display dominant antiferromagnetic interactions between MnII ions through μ2-O bridges. In addition, 1–3 also display favourable electrochemiluminescence (ECL) properties.

Tunable Ferromagnetic Strength in Niccolite Structural Heterometallic Formate Framework Based on Orthogonal Magnetic Orbital Interactions

A series of heterometallic formate framework templated by amines were solvothermally prepared. They feature the formula of [A^I][CrM^II(HCO₂)₆] (A^I = NH₄H₂O^I and M = Mn for 1, A^I = CH₃NH₃^I and M = Fe for 2, A^I = CH₃NH₂CH₃^I and M = Co for 3, A^I = CH₃NH₃^I and M = Ni for 4). The title compounds exhibit isostructural niccolite architectures with differences only in the host metal ions and guest amines. Tunable ferromagnetic (FO) strength was realized in the resulting framework under the guidance of orthogonal magnetic orbital analysis of Cr^III (t_2g³e_g) and M^II (t_2g³e_g² for Mn^II, t_2g⁴e_g² for Fe^II, t_2g⁵e_g² for Co^II, t_2g⁶e_g² for Ni^II) ions. The magnetic ordering temperatures derived from the experimental magnetic measurements for 1-4 are lower than 2, 10.3, 7.6, and 22.0 K, respectively. Notably, thanks to the weak FO coupling between Cr^III and Mn^II ions, compound 1 displays a large magnetocaloric effect bearing the maximum of magnetic entropy change (-Δ S_m^max) up to 43.9 J kg^-1 K^-1 with Δ H = 7 T and T = 3.5 K, larger than most reported transition metal-based complexes and commercial gadolinium gallium garnet (Gd₃Ga₅O₁₂) (-Δ S_m^max = 38.4 J kg^-1 K^-1 with Δ H = 7 T). From 1, 2/3, to 4, an enhancement of the magnetic ordering temperature is observable due to the increasing strength of FO interactions between Cr^III and M^II ions. Our work provides a successful instance to modulate the strength of FO exchange via analyzing the orthogonal magnetic orbitals of heterometallic ions.

Hydrothermal generation, structural versatility and properties of metal(ii)-organic architectures driven by a pyridine-tricarboxylic acid

A new series of metal(ii) coordination compounds driven by a pyridine-tricarboxylate block was generated, their structural features, magnetic, luminescent or photocatalytic properties were explored.

Single-chain magnets assembled in cobalt(ii) metal–organic frameworks

This feature article discusses the advantages, progress and prospects of constructing single-chain magnets in metal–organic frameworks.

Five new coordination polymers with a Y-shaped N-heterocyclic carboxylic acid: structural diversity, bifunctional luminescence sensing and magnetic properties

Five novel CPs have been synthesized under solvothermal conditions. The results show that 1 and 2 present high sensing ability for NACs and Fe³⁺ ions, and there exist ferromagnetic interaction in 3/4 and antiferromagnetic interaction in 5.

A Zn(ii) metal–organic framework constructed by a mixed-ligand strategy for CO2 capture and gas separation

A microporous Zn(ii) metal–organic framework has been assembled using a mixed-ligand strategy, and it exhibits high capture ability for CO₂ and good selectivity for CO₂/CH₄, C₂H₆/CH₄ and C₃H₈/CH₄.

Spectroelectrochemical studies of the redox active tris[4-(triazol-1-yl)phenyl]amine linker and redox state manipulation of Mn(ii)/Cu(ii) coordination frameworks

In situ spectroelectrochemical methods were conducted to investigate the redox active tris(4-(1H-1,2,4-triazol-1-yl)phenyl)amine (TTPA) ligand and its incorporation into the solid state of Mn(ii) and Cu(ii) frameworks.

Solid-state structure and antimicrobial and cytotoxicity studies of a cucurbit[6]uril-like Cu6L4 constructed from 3,5-bis[(1H-tetrazol-5-yl)methyl]-4H-1,2,4-triazol-4-amine

3,5-Bis[(1H-tetrazol-5-yl)methyl]-4H-1,2,4-triazol-4-amine (H₂L) associates under deprotonation with CuSO₄ in aqueous medium to form a new waisted barrel-shaped M₆L₄ cluster, namely hexaaquatetrakis{μ₄-3,5-bis[(1H-tetrazol-5-yl)methyl]-4H-1,2,4-triazol-4-amine}-μ₄-sulfato-hexacopper(II) sulfate hydrate, [Cu₆(SO₄)(C₆H₆N₁₂)₄(H₂O)₆]SO₄·nH₂O (n = ∼23) (1). Cluster 1 resembles concave cucurbit[6]uril and has one disordered sulfate anion trapped inside the cage, which additionally stabilizes the Cu₆ unit. The Cu^II ions have either a square-pyramidal or a distorted octahedral geometry. The equatorial positions are filled by N atoms from the L^2- ligand, while the axial positions are occupied by coordinated water molecules and O atoms of the sulfate counter-ion. In the solid state, the Cu₆ clusters are connected through a large number of hydrogen bonds formed by uncoordinated water molecules and an additional sulfate anion. The compound shows good antimicrobial activity against E. coli tested with the Kirby Bauer approach. In addition, the cell viability towards HeLa and L-929 cells was studied.

Four 3D coordination polymers based on layers with single syn-anti carboxylate bridges: synthesis, structures, and magnetic properties

Four novel coordination polymers (CPs) based on a new 4-(3,5-dicarboxylphenyl) picolinic acid ligands (H3L), [M3(L)2(H2O)6]·4H2O (M3 = Mn3, 1; Co3, 2; Ni3, 3, Co1.01Ni1.99, 4), have been hydrothermally synthesized, and structurally and magnetically characterized. In these isomorphous CPs, octahedrally coordinated metal ions are linked by the single syn-anti carboxylate bridge (μ-COO) to give linear trinuclear motifs. The motifs are connected through the other single syn-anti carboxylate bridge (μ-COO) to give a 2D (4,4) layer, and the layers are interlinked by the L ligands into 3D frameworks. Magnetic measurement indicates that antiferromagnetic interactions between metal ions are mediated through the single syn-anti carboxylate bridges in 1 and 2, while the same carboxylate bridges in 3 transmit ferromagnetic couplings. The bimetallic CP 4 shows interesting complicated magnetic behaviors due to the competition effect of Co(ii) and Ni(ii) ions.

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.

Reversible crystal-to-amorphous structural transformations and magnetic variations in single end-on azide-bridged MII (M = Mn, Ni) coordination polymers

Azide-bridged coordination polymers undergo reversible crystal-to-amorphous phase transformations during the hydration–dehydration process.

Solution behavior and magnetic properties of a novel nonanuclear copper(ii) cluster

A {Cu9} nanocluster was constructed from a new multidentate pyrazole–alcohol ligand and various small sterically-hindering anions. The ESI-MS was for the first time applied to Cu cluster chemistry to detect the solution behaviour and possible assembly mechanism of the {Cu9} cluster. The cluster also exhibited antiferromagnetic behaviour.

Three new Zn-based metal–organic frameworks exhibiting selective fluorescence sensing and photocatalytic activity

Three MOFs with different 2D networks have been crystallised in a one-pot solvothermal reaction. They all display high sensitivity in the detection of ACE and relatively good photocatalytic activity in the degradation of RhB.

Assembly of ZnII-coordination polymers constructed from benzothiadiazole functionalized bipyridines and V-shaped dicarboxylic acids: topology variety, photochemical and visible-light-driven photocatalytic properties

Photocatalytic properties of four benzothiadiazole functionalized coordination polymers have been reported.

Heterometallic lanthanide-centred [NiII6LnIII] rings

The syntheses, structures and magnetic properties of three new hetero-heptametallic [Ni₆Ln] complexes are reported.

Two isomorphous azide/formate Mn(ii) coordination polymers show spin-canted antiferromagnetism only in the formate system

We reported two isomorphous azide/formate Mn^II complexes: the azide complex had normal antiferromagnetic coupling, while a canted antiferromagnet with a Néel temperature of T_N = 38.5 K was obtained in the formate system.

Two isomorphous coordination polymer-derived metal oxides as high-performance anodes for lithium-ion batteries

Two Co₃O₄ and NiO anodes for LIBs derived from novel, isomorphous 2D coordination polymers displayed high rate cycling performance.

Two hybrid transition metal triphosphonates decorated with a tripodal imidazole ligand: synthesis, structures and properties

Two transition-metal triphosphonates with pillar-layered structures were synthesized and characterized. The luminescence, magnetic and proton conductive properties were investigated.

Diversified magnetic behaviors of new nickel(ii) and copper(ii) azido coordination polymers templated by diethyl or triethyl amines

The reactions of Ni^II or Cu^II ions with N₃⁻ anions in the presence of templated diethyl or triethyl amines afford three new azido-bridged coordination polymers, which exhibit metamagnetism, spin glass and canted ferromagnetism, respectively.

Self-assembly, structures, magnetic properties and solution behaviors of six mixed-valence cobalt clusters

Six novel mixed-valence cobalt clusters with flexible {Co^II_xCo^III_y} cores have been constructed via in situ synthesis and stepwise synthesis routes. Their solution behaviors and possible assembly evolutions were detected by HRESI-MS. All of them also show interesting magnetic behaviours.