Synthesis,Crystal Structures,and Properties of Copper(II), Zinc(II), and Cadmium(II) Coordination Polymers Based on 5‐Nitro‐isophthalate and 1,2‐(2‐Pyridyl)‐1,2,4‐triazole

Three coordination polymers, namely {[Cu(5‐nipa)(L²²)](H₂O)₂}_n ( 1 ), [Zn(5‐nipa)(L²²)(H₂O)]_n ( 2 ), and {[Cd₂(5‐nipa)₂(L²²)(H₂O)₃](H₂O)_3.6}_n ( 3 ), were prepared under similar synthetic method based on 1,2‐(2‐pyridyl)‐1,2,4‐triazole (L²²) and ancillary ligand 5‐nitro‐isophthalic acid (5‐H₂nipa) with Cu^II, Zn^II, and Cd^II perchlorate, respectively. All the complexes were characterized by IR spectroscopy, elemental analysis, and powder X‐ray diffraction (PXRD) patterns. Single‐crystal X‐ray diffraction indicates that complexes 1 and 2 show similar 1D chain structures, whereas complex 3 exhibits the 2D coordination network with hcb topology. The central metal atoms show distinct coordination arrangements ranging from distorted square‐pyramid for Cu^II in 1 , octahedron for Zn^II in 2 , to pentagonal‐bipyramid for Cd^II in 3 . The L²² ligand adopts the same (η³,μ₂) coordination fashion in complexes 1 – 3 , while the carboxyl groups of co‐ligand 5‐nipa^2– adopt monodentate fashion in 1 and 2 and bidentate chelating mode in 3 . These results indicate that the choice of metal ions exerts a significant influence on governing the target complexes. Furthermore, thermal stabilities of complexes 1 – 3 and photoluminescent properties of 2 and 3 were also studied in the solid state.     

A three‐dimensional ZnII coordination framework: poly[[μ2‐(E)‐1,2‐bis(pyridin‐4‐yl)ethene][μ4‐(E)‐2,2′‐(diazene‐1,2‐diyl)dibenzoato][μ2‐(E)‐2,2′‐(diazene‐1,2‐diyl)dibenzoato]dizinc(II)]

In the title coordination polymer, [Zn₂(C₁₄H₈N₂O₄)₂(C₁₂H₁₀N₂)]_n, the asymmetric unit contains one Zn^II cation, two halves of 2,2′‐(diazene‐1,2‐diyl)dibenzoate anions (denoted L²⁻) and half of a 1,2‐bis(pyridin‐4‐yl)ethene ligand (denoted bpe). The three ligands lie across crystallographic inversion centres. Each Zn^II centre is four‐coordinated by three O atoms of bridging carboxylate groups from three L²⁻ ligands and by one N atom from a bpe ligand, forming a tetrahedral coordination geometry. Two Zn^II atoms are bridged by two carboxylate groups of L²⁻ ligands, generating a [Zn₂(CO₂)₂] ring. Each loop serves as a fourfold node, which links its four equivalent nodes via the sharing of four L²⁻ ligands to form a two‐dimensional [Zn₂L₄]_n net. These nets are separated by bpe ligands acting as spacers, producing a three‐dimensional framework with a 4⁶6⁴ topology. Powder X‐ray diffraction and solid‐state photoluminescence were also measured.     

Six Coordination Polymers based on 4‐(1H‐Imidazol‐1‐yl)phthalic Acid: Structural Diversities,Magnetism and Luminescence Properties

The coordination polymers (CPs), [Ni(L)(H₂O)₄]_n ( 1 ), [Co(HL)₂(H₂O)₂]_n ( 2 ), {[Cu(L)(H₂O)₃] · H₂O}_n ( 3 ), [Mn(L)(H₂O)₂]_n ( 4 ), [Cd(L)(H₂O)₂]_n ( 5 ), and {[Zn₂(L)₂] · H₂O}_n ( 6 ), were solvothermally synthesized by employing the imidazol‐carboxyl bifunctional ligand 4‐(1H‐imidazol‐1‐yl) phthalic acid (H₂L). Single‐crystal X‐ray diffraction indicated that the L^2–/HL^– ligands display various coordination modes with different metal ions in 1 – 6 . Complexes 1 and 2 show one‐dimensional (1D) chain structures, whereas complexes 3 – 6 show 2D layered structures. The magnetic properties of these complexes were investigated. Complexes 1 and 3 indicate weak ferromagnetic interactions, whereas complexes 2 and 4 demonstrate antiferromagnetic interactions. In addition, luminescence properties of 5 and 6 were measured and studied in detail.     

Pseudohalide‐directed Assembly of Two Zinc(II) Coordination Polymers with a 3,4‐Bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole Tecton

The zinc(II) pseudohalide complexes {[Zn(L³³⁴)(SCN)₂(H₂O)](H₂O)₂}_n ( 1 ) and [Zn(L³³⁴)(dca)₂]_n ( 2 ) were synthesized and characterized using the ligand 3,4‐bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole (L³³⁴) and ZnCl₂ in presence of thiocyanate (SCN^–) and dicynamide [dca, N(CN)₂^–] respectively. Single‐crystal X‐ray structural analysis revealed that the central Zn^II atoms in both complexes have similar octahedral arrangement. Compound 1 has a 2D sheet structure bridged by bidentate L³³⁴ and double μ_N,S‐thiocyanate anions, whereas complex 2 , incorporating with two monodentate dicynamide anions, displays a two‐dimensional coordination framework bridged by tetradentate L³³⁴ ligand. Structural analysis demonstrated that the influence of pseudohalide anions plays an important role in determining the resultant structure. Both complexes were characterized by IR spectroscopy, microanalysis, and powder X‐ray diffraction techniques. In addition, the solid fluorescence and thermal stability properties of both complexes were investigated.     

A novel one‐dimensional double‐chain‐like ZnII coordination polymer: poly[bis(1‐benzyl‐1H‐imidazole‐κN3)tris(μ‐cyanido‐κ2C:N)(cyanido‐κC)disilver(I)zinc(II)]

One of most interesting systems of coordination polymers constructed from the first‐row transition metals is the porous Zn^II coordination polymer system, but the numbers of such polymers containing N‐donor linkers are still limited. The title double‐chain‐like Zn^II coordination polymer, [Ag₂Zn(CN)₄(C₁₀H₁₀N₂)₂]_n, presents a one‐dimensional linear coordination polymer structure in which Zn^II ions are linked by bridging anionic dicyanidoargentate(I) units along the crystallographic b axis and each Zn^II ion is additionally coordinated by a terminal dicyanidoargentate(I) unit and two terminal 1‐benzyl‐1H‐imidazole (BZI) ligands, giving a five‐coordinated Zn^II ion. Interestingly, there are strong intermolecular Ag^I…Ag^I interactions between terminal and bridging dicyanidoargentate(I) units and C—H…π interactions between the phenyl rings of BZI ligands of adjacent one‐dimensional linear chains, providing a one‐dimensional linear double‐chain‐like structure. The supramolecular three‐dimensional framework is stabilized by C—H…π interactions between the phenyl rings of BZI ligands and by Ag^I…Ag^I interactions between adjacent double chains. The photoluminescence properties have been studied.     

Three Novel 1‐H‐Benzimidazole‐5‐Carboxylate‐Based Nickel(II)/Cobalt(II) Coordination Polymers: Synthesis,Crystal Structures,Luminescent, and Magnetic Properties

Three 1H‐benzimidazole‐5‐carboxylate (Hbic^–)‐based coordination polymers, {[Ni(H₂O)(Hbic)₂] · 2H₂O}_n ( 1 ), {[Ni(H₂O)₂(Hbic)₂] · 3H₂O}_n ( 2 ), and {[Co₂(H₂O)₄(Hbic)₄] · 4DMF · 3H₂O}_n ( 3 ) were obtained by reactions of the ligand H₂bic and Ni^II or Co^II salts in the presence of different structure directing molecules. They were structurally characterized by single‐crystal X‐ray diffraction, IR spectra, elemental analysis, thermal stability, luminescent, and magnetic measurements. Structural analysis suggests that the three polymers exhibit a 2D (4, 4) layer for 1 and 1D linear double chains for both 2 and 3 due to the variable binding modes and the specific spatial orientation of the Hbic^– ligand towards the different paramagnetic metal ions, which were further aggregated into different 3D supramolecular architectures by popular hydrogen‐bonding interactions. Weak and comparable antiferromagnetic couplings mediating by Hbic^– bridge are observed between the neighboring spin carriers for 2 and 3 , respectively. Additionally, complexes 1 – 3 also display different luminescence emissions at room temperature due to the ligand‐to‐metal charge transfer.     

Homo‐ and Heteronuclear Compounds with a Symmetrical Bis‐hydrazone Ligand: Synthesis,Structural Studies,and Luminescent Properties

Nine new coordination compounds have been synthesized by the reaction of salts of bivalent metal ions (a=Zn^II, b=Cu^II, c=Ni^II, d=Co^II) with the bis(benzoylhydrazone) derivative of 4,6‐diacetylresorcinol (H₄L). Three kinds of complexes have been obtained: homodinuclear compounds [M₂(H₂L)₂]?nH₂O ( 1 a , 1 b , 1 c , and 1 d ), homotetranuclear compounds [M₄(L)₂]?n(solv) ( 2 a and 2 c ), and heterotetranuclear compounds [Zn₂M₂(L)₂]?n(solv) ( 2 ab , 2 ac , and 2 ad ). The structures of the free ligand H₄L?2 DMSO and its complexes [Zn₂(H₂L)₂(DMSO)₂] ( 1 a* ), [Zn₄(L)₂(DMSO)₆] ( 2 a* ), and [Zn_0.45Cu_3.55(L)₂(DMSO)₆]?2 DMSO ( 2 ab* ) were elucidated by single‐crystal X‐ray diffraction. The ligand shows luminescence properties and its fluorimetric behavior towards M^II metals (M=Zn, Cu, Ni and Co) has been studied. Furthermore, the solid‐state luminescence properties of the ligand and compounds have been determined at room temperature. ¹H NMR spectroscopic monitoring of the reaction of H₄L with Zn^II showed the deprotonation sequence of the OH/NH groups upon metal coordination. Heteronuclear reactions have also been monitored by using ESI‐MS and spectrofluorimetric techniques.     

A new one‐dimensional nickel metal–organic framework: catena‐poly[[[diaquabis(4‐{[(1‐phenyl‐1H‐tetrazol‐5‐yl)sulfanyl]methyl}benzoato‐κO)nickel(II)]‐μ‐4,4′‐bipyridine‐κ2N:N′] monohydrate]

The title complex, {[Ni(C₁₅H₁₁N₄O₂S)₂(C₁₀H₈N₂)(H₂O)₂]·H₂O}_n, was synthesized by the reaction of nickel chloride, 4‐{[(1‐phenyl‐1H‐tetrazol‐5‐yl)sulfanyl]methyl}benzoic acid (HL) and 4,4′‐bipyridine (bpy) under hydrothermal conditions. The asymmetric unit contains two half Ni^II ions, each located on an inversion centre, two L⁻ ligands, one bpy ligand, two coordinated water molecules and one unligated water molecule. Each Ni^II centre is six‐coordinated by two monodentate carboxylate O atoms from two different L⁻ ligands, two pyridine N atoms from two different bpy ligands and two terminal water molecules, displaying a nearly ideal octahedral geometry. The Ni^II ions are bridged by 4,4′‐bipyridine ligands to afford a linear array, with an Ni...Ni separation of 11.361 (1) Å, which is further decorated by two monodentate L⁻ ligands trans to each other, resulting in a one‐dimensional fishbone‐like chain structure. These one‐dimensional fishbone‐like chains are further linked by O—H...O, O—H...N and C—H...O hydrogen bonds and π–π stacking interactions to form a three‐dimensional supramolecular architecture. The thermal stability of the title complex was investigated via thermogravimetric analysis.     

Syntheses,Structures, and Magnetism of Trinuclear Zn2Ln Complexes with 2,6‐Dipicolinoylbis(N,N‐diethylthiourea)

The bifunctional ligand 2,6‐dipicolinoylbis(N,N‐diethylthiourea) (H₂L) readily reacts with mixtures of Zn(CH₃COO)₂ and LnCl₃ in MeOH at ambient temperature with formation of trinuclear heterobimetallic complexes [Zn₂Ln(L)₂(OAc)₃] ( 1a – 1f ) (Ln = Ce, Nd, Sm, Gd, Dy, Er). The X‐ray single‐crystal diffraction and structural studies of the complexes revealed their isostructural nature, in which two doubly‐charged ligands {L^2–} bind two Zn²⁺ ions with the terminal acylthiourea sites and one Ln³⁺ ion with the central 2,6‐pyridinedicarboxamide site. In the complexes, the coordination numbers of Ln^III and Zn^II ions are 9 and 5, respectively. Magnetic properties of the complexes were studied by temperature‐dependent dc magnetic measurements. The observed μ_eff values at room temperature are all closed to the calculated values. Fitting χ_M and M data of [Zn₂Gd(L)₂(OAc)₃] ( 1d ) shows a g_iso value of 1.94.     

Three novel topologically different metal–organic frameworks built from 3‐nitro‐4‐(pyridin‐4‐yl)benzoic acid

The design and synthesis of metal–organic frameworks (MOFs) have attracted much interest due to the intriguing diversity of their architectures and topologies. However, building MOFs with different topological structures from the same ligand is still a challenge. Using 3‐nitro‐4‐(pyridin‐4‐yl)benzoic acid (HL) as a new ligand, three novel MOFs, namely poly[[(N,N‐dimethylformamide‐κO)bis[μ₂‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ³O,O′:N]cadmium(II)] N,N‐dimethylformamide monosolvate methanol monosolvate], {[Cd(C₁₂H₇N₂O₄)₂(C₃H₇NO)]·C₃H₇NO·CH₃OH}_n, ( 1 ), poly[[(μ₂‐acetato‐κ²O:O′)[μ₃‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ³O:O′:N]bis[μ₃‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ⁴O,O′:O′:N]dicadmium(II)] N,N‐dimethylacetamide disolvate monohydrate], {[Cd₂(C₁₂H₇N₂O₄)₃(CH₃CO₂)]·2C₄H₉NO·H₂O}_n, ( 2 ), and catena‐poly[[[diaquanickel(II)]‐bis[μ₂‐3‐nitro‐4‐(pyridin‐4‐yl)benzoato‐κ²O:N]] N,N‐dimethylacetamide disolvate], {[Ni(C₁₂H₇N₂O₄)₂(H₂O)₂]·2C₄H₉NO}_n, ( 3 ), have been prepared. Single‐crystal structure analysis shows that the Cd^II atom in MOF ( 1 ) has a distorted pentagonal bipyramidal [CdN₂O₅] coordination geometry. The [CdN₂O₅] units as 4‐connected nodes are interconnected by L^? ligands to form a fourfold interpenetrating three‐dimensional (3D) framework with a dia topology. In MOF ( 2 ), there are two crystallographically different Cd^II ions showing a distorted pentagonal bipyramidal [CdNO₆] and a distorted octahedral [CdN₂O₄] coordination geometry, respectively. Two Cd^II ions are connected by three carboxylate groups to form a binuclear [Cd₂(COO)₃] cluster. Each binuclear cluster as a 6‐connected node is further linked by acetate groups and L^? ligands to produce a non‐interpenetrating 3D framework with a pcu topology. MOF ( 3 ) contains two crystallographically distinct Ni^II ions on special positions. Each Ni^II ion adopts an elongated octahedral [NiN₂O₄] geometry. Each Ni^II ion as a 4‐connected node is linked by L^? ligands to generate a two‐dimensional network with an sql topology, which is further stabilized by two types of intermolecular OW—HW…O hydrogen bonds to form a 3D supramolecular framework. MOFs ( 1 )–( 3 ) were also characterized by powder X‐ray diffraction, IR spectroscopy and thermogravimetic analysis. Furthermore, the solid‐state photoluminescence of HL and MOFs ( 1 ) and ( 2 ) have been investigated. The photoluminescence of MOFs ( 1 ) and ( 2 ) are enhanced and red‐shifted with respect to free HL. The gas adsorption investigation of MOF ( 2 ) indicates a good separation selectivity (71) of CO₂/N₂ at 273 K (i.e. the amount of CO₂ adsorption is 71 times higher than N₂ at the same pressure).     

Binuclear and chain‐structure zinc(II) complexes constructed from 3,4‐dimethoxy‐trans‐cinnamic acid and N‐donor coligands 4‐(1H‐pyrazol‐3‐yl)pyridine and 4,4′‐bipyridine

3,4‐Dimethoxy‐trans‐cinnamic acid (Dmca) reacts with zinc sulfate in the presence of 4‐(1H‐pyrazol‐3‐yl)pyridine (L₁) or 4,4′‐bipyridine (L₂) under hydrothermal conditions to afford two mixed‐ligand coordination complexes, namely tetrakis(μ‐3,4‐dimethoxy‐trans‐cinnamato‐κ²O:O′)bis[[4‐(1H‐pyrazol‐3‐yl)pyridine]zinc(II)] heptahydrate, [Zn₂(C₁₁H₁₁O₄)₄(C₈H₇N₃)₂]·7H₂O or [Zn₂(Dmca)₄(L₁)₂]·7H₂O, (I), and catena‐poly[[bis(3,4‐dimethoxy‐trans‐cinnamato‐κO)zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′], [Zn(C₁₁H₁₁O₄)₂(C₁₀H₈N₂)]_n or [Zn(Dmca)₂(L₂)]_n, (II). The Zn^II centres in the two compounds display different coordination polyhedra. In complex (I), the Zn^II cation is five‐coordinated with a pseudo‐square‐pyramidal geometry, while in complex (II) the Zn^II cation sits on a twofold axis and adopts a distorted tetrahedral coordination environment. Complex (I) features a centrosymmetric binuclear paddle‐wheel‐like structure, while complex (II) shows a chain structure. This study emphasizes the significant effect of the coordination mode of both carboxylate‐group and N‐donor coligands on the formation of complex structures.     

A self‐penetrated three‐dimensional zinc(II) coordination framework based on 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoic acid and 1,3‐bis[(imidazol‐1‐yl)methyl]benzene ligands: synthesis,structure and properties

With the rapid development of metal–organic frameworks (MOFs), a variety of MOFs and their derivatives have been synthesized and reported in recent years. Commonly, multifunctional aromatic polycarboxylic acids and nitrogen‐containing ligands are employed to construct MOFs with fascinating structures. 4,4′,4′′‐(1,3,5‐Triazine‐2,4,6‐triyl)tribenzoic acid (H₃TATB) and the bidentate nitrogen‐containing ligand 1,3‐bis[(imidazol‐1‐yl)methyl]benzene (bib) were selected to prepare a novel Zn^II‐MOF under solvothermal conditions, namely poly[[tris{μ‐1,3‐bis[(imidazol‐1‐yl)methyl]benzene}bis[μ₃‐4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoato]trizinc(II)] dimethylformamide disolvate trihydrate], {[Zn₃(C₂₄H₁₂N₃O₆)₂(C₁₄H₁₄N₄)₃]·2C₃H₇NO·3H₂O}_n ( 1 ). The structure of 1 was characterized by single‐crystal X‐ray diffraction, IR spectroscopy and powder X‐ray diffraction. The properties of 1 were investigated by thermogravimetric and fluorescence analysis. Single‐crystal X‐ray diffraction shows that 1 belongs to the monoclinic space group Pc. The asymmetric unit contains three crystallographically independent Zn^II centres, two 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoate (TATB^3?) anions, three complete bib ligands, one and a half free dimethylformamide molecules and three guest water molecules. Each Zn^II centre is four‐coordinated and displays a distorted tetrahedral coordination geometry. The Zn^II centres are connected by TATB^3? anions to form an angled ladder chain with large windows. Simultaneously, the bib ligands link Zn^II centres to give a helical Zn–bib–Zn chain. Furthermore, adjacent ladders are bridged by Zn–bib–Zn chains to form a fascinating three‐dimensional self‐penetrated framework with the short Schläfli symbol 6⁵·7·8¹³·9·10. In addition, the luminescence properties of 1 in the solid state and the fluorescence sensing of metal ions in suspension were studied. Significantly, compound 1 shows potential application as a fluorescent sensor with sensing properties for Zr⁴⁺ and Cu²⁺ ions.     

Metallkomplexe mit biologisch wichtigen Liganden. CLXVI Metallkomplexe mit Ferrocenylmethyl‐L‐cysteinat und 1,1′‐Ferrocenylbis‐(methyl‐L‐cysteinat) als Liganden

Metal Complexes of Biologically Important Ligands. CLXVI Metal Complexes with Ferrocenylmethylcysteinate and 1,1′‐Ferrocenylbis‐(methylcysteinate) as Ligands A series of complexes of transition metal ions ( Cr³⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ ) and of lanthanide ions ( La³⁺, Nd³⁺, Gd³⁺, Dy³⁺, Lu³⁺ ) with the anions of ferrocenylmethyl‐L‐cysteine [(C₅H₅)Fe(C₅H₄CH(R)SCH₂CH(NH₃⁺)CO₂^?] (L¹) and with the dianions of 1,1′‐ferrocenylbis(methyl‐L‐cysteine) [Fe(C₅H₄CH(R)SCH₂CH(NH₃⁺) CO₂^?)₂] (R = H, Me, Ph) (L²) as N,O,S‐donors were prepared. With the monocysteine ferrocene derivative L¹ as ligands complexes [M^IIL¹₂] or [Cr^IIIL¹₂]Cl type complexes are formed whereas the bis(cysteine) ligand L² yields insoluble complexes of type [ML²]_n, presumably as coordination polymers. The magnetic moments of [Mn^IIL²]_n, [Pr^IIIL²]_n(OH)_n and [Dy^IIIL²]_n(OH)_n exhibit “normal” paramagnetism.     

Syntheses,Structures and Characterization of Four Metal‐Organic Frameworks constructed by 2,2′,6,6′‐Tetramethoxy‐4,4′‐biphenyldicarboxylic Acid

Four metal‐organic frameworks (MOFs), {[Mn_3.5L(OH)(HCOO)₄(DMF)] · H₂O} ( 1 ), {[In_2.5L₂O(OH)_1.5(H₂O)₂] · DMF · CH₃CN · 2H₂O} ( 2 ), {[Pb₄L₃O(DMA)] · CH₃CN} ( 3 ), and {[LaL(NO₃)(DMF)₂] · 2H₂O} ( 4 ) were synthesized by utilizing the ligand 2,2′,6,6′‐tetramethoxy‐4,4′‐biphenyldicarboxylic acid (H₂L) via solvothermal methods. All MOFs were characterized by single‐crystal X‐ray diffraction, powder X‐ray diffraction, thermogravimetric analysis, and infrared spectroscopy. In 1 , the Mn²⁺ ions are interconnected by formic groups in situ produced via DMF decomposition to form a rare 2D macrocyclic plane, which is further linked by L^2– to construct the final 3D network. In 2 , 1D zip‐like infinite chain is formed and then interconnected to build the 3D framework. In 3 , a [Pb₆(μ₄‐O)₂(O₂C)₁₀(DMA)₂] cluster with a centrosymmetric [Pb₆(μ₄‐O)₂]⁸⁺ octahedral core is formed in the 3D structure. In 4 , the La³⁺ ions are connected with each other through carboxylate groups of L^2– to generate 1D zigzag chain, which is further linked by L^2– to construct a 3D network with sra topology. Solid photoluminescence properties of 3 and 4 were also investigated.     

Construction of Two 3D Main Group Coordination Polymers Based on 2‐(2‐Pyridyl)‐4,5‐imidazole‐dicarboxylic Acid: Structures and Luminescent Properties

Two main group coordination polymers based on 2‐(2‐pyridyl)‐4,5‐imidazole‐dicarboxylic acid (H₃oPyIDC), namely [Ba(H₂oPyIDC)₂(H₂O)]_n ( 1 ) and [Pb₂(HoPyIDC)₂]_n ( 2 ) are obtained under hydrothermal conditions. In compound 1 , the Ba²⁺ cations and HoPyIDC^2– anions are connected to a 1D chain, and the 1D chains are further interconnected by Ba–O bonds, forming a 3D 3‐connected framework. In compound 2 , a 2D layer with (4,4) topology is formed by Pb^II ions and HoPyIDC^2– anions. The 2D layer are pillared by HoPyIDC^2–, yielding a 3D (3,4)‐connected framework. The thermogravimetric analyses and luminescence properties of compounds 1 and 2 are also investigated.     

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.     

Two Heterometallic–Organic Frameworks Composed of Iron(III)‐Salen‐Based Ligands and d10 Metals: Gas Sorption and Visible‐Light Photocatalytic Degradation of 2‐Chlorophenol

Two examples of heterometallic–organic frameworks (HMOFs) composed of dicarboxyl‐functionalized Fe^III‐salen complexes and d¹⁰ metals (Zn, Cd), [Zn₂(Fe‐L)₂(μ₂‐O)(H₂O)₂] ? 4 DMF ? 4 H₂O ( 1 ) and [Cd₂(Fe‐L)₂(μ₂‐O)(H₂O)₂] ? 2 DMF ? H₂O ( 2 ) (H₄L=1,2‐cyclohexanediamino‐N,N′‐bis(3‐methyl‐5‐carboxysalicylidene), have been synthesized and structurally characterized. In 1 and 2 , each square‐pyramidal Fe^III atom is embedded in the [N₂O₂] pocket of an L^4? anion, and these units are further bridged by a μ₂‐O anion to give an (Fe‐L)₂(μ₂‐O) dimer. The two carboxylate groups of each L^4? anion bridge Zn^II or Cd^II atoms to afford a 3D porous HMOF. The gas sorption and magnetic properties of 1 and 2 have been studied. Remarkably, 1 and 2 show activity for the photocatalytic degradation of 2‐chlorophenol (2‐CP) under visible‐light irradiation, which, to the best of our knowledge, is the first time that this has been observed for Fe^III‐salen‐based HMOFs.     

Controlled Synthesis of Heterotrimetallic Single‐Chain Magnets from Anisotropic High‐Spin 3 d–4 f Nodes and Paramagnetic Spacers

By using the node‐and‐spacer approach in suitable solvents, four new heterotrimetallic 1D chain‐like compounds (that is, containing 3d–3d′–4f metal ions), {[Ni(L)Ln(NO₃)₂(H₂O)Fe(Tp*)(CN)₃] ? 2 CH₃CN ? CH₃OH}_n (H₂L=N,N′‐bis(3‐methoxysalicylidene)‐1,3‐diaminopropane, Tp*=hydridotris(3,5‐dimethylpyrazol‐1‐yl)borate; Ln=Gd ( 1 ), Dy ( 2 ), Tb ( 3 ), Nd ( 4 )), have been synthesized and structurally characterized. All of these compounds are made up of a neutral cyanide‐ and phenolate‐bridged heterotrimetallic chain, with a {? Fe? C?N? Ni(? O? Ln)? N?C? }_n repeat unit. Within these chains, each [(Tp*)Fe(CN)₃]^? entity binds to the Ni^II ion of the [Ni(L)Ln(NO₃)₂(H₂O)]⁺ motif through two of its three cyanide groups in a cis mode, whereas each [Ni(L)Ln(NO₃)₂(H₂O)]⁺ unit is linked to two [(Tp*)Fe(CN)₃]^? ions through the Ni^II ion in a trans mode. In the [Ni(L)Ln(NO₃)₂(H₂O)]⁺ unit, the Ni^II and Ln^III ions are bridged to one other through two phenolic oxygen atoms of the ligand (L). Compounds 1 – 4 are rare examples of 1D cyanide‐ and phenolate‐bridged 3d–3d′–4f helical chain compounds. As expected, strong ferromagnetic interactions are observed between neighboring Fe^III and Ni^II ions through a cyanide bridge and between neighboring Ni^II and Ln^III (except for Nd^III) ions through two phenolate bridges. Further magnetic studies show that all of these compounds exhibit single‐chain magnetic behavior. Compound 2 exhibits the highest effective energy barrier (58.2 K) for the reversal of magnetization in 3d/4d/5d–4f heterotrimetallic single‐chain magnets.     

Construction of Four Coordination Polymers based on 2‐[4‐(Pyridine‐4‐yl)phenyl]‐1H‐imidazole‐4,5‐dicarboxylic Acid

The imidazole‐based dicarboxylate ligand 2‐(4‐(pyridin‐4‐yl)phenyl)‐1H‐imidazole‐4,5‐dicarboxylic acid (H₃PyPhIDC), was synthesized and its coordination chemistry was studied. Solvothermal reactions of Ca^II, Mn^II, Co^II, and Ni^II ions with H₃PyPhIDC produced four coordination polymers, [Ca(μ₃‐HPyPhIDC)(H₂O)₂]_n ( 1 ), {[M₃(μ₂‐H₂PyPhIDC)₂(μ₃‐HPyPhIDC)₂₆(H₂O)₂] · 6H₂O}_n [M = Mn ( 2 ), Co ( 3 )], and {[Ni(μ₃‐HPyPhIDC)(H₂O)] · H₂O}_n ( 4 ). Compounds 1 – 4 were analyzed by IR spectroscopy, elemental analyses, and single‐crystal and powder X‐ray diffraction. Compound 1 displays a one‐dimensional (1D) infinite chain. Compounds 2 and 3 are of similar structure, showing 2D network structures with a (4,4) topology based on trinuclear clusters. Compound 4 has another type of 2D network structure with a 3‐connected (4.8²) topology. The results revealed that the structural diversity is attributed to the coordination numbers and geometries of metal ions as well as the coordination modes and conformations of H₃PyPhIDC. Moreover, the thermogravimetric analyses of all the compounds as well as luminescence properties of the H₃PyPhIDC ligand and compound 1 were also studied.     

Synthesis,structure and selective luminescence sensing for iron(III) ions of a three‐dimensional zinc(II) (4,6)‐connected coordination network

Coordination polymers constructed from conjugated organic ligands and metal ions with a d¹⁰ electronic configuration exhibit intriguing properties for chemical sensing and photochemistry. A Zn^II‐based coordination polymer, namely poly[aqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)(μ₂‐4,4′‐bipyridine)dizinc(II)], [Zn₂(C₁₆H₆O₈)(C₁₀H₈N₂)(H₂O)₂]_n or [Zn₂(m,m‐bpta)(4,4′‐bipy)(H₂O)₂]_n, was synthesized from a mixture of biphenyl‐3,3′,5,5′‐tetracarboxylic acid [H₄(m,m‐bpta)], 4,4′‐bipyridine (4,4′‐bipy) and Zn(NO₃)₂·6H₂O under solvothermal conditions. The title complex has been structurally characterized by IR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction and powder X‐ray diffraction analysis, and features a μ₆‐coordination mode. The Zn^II ions adopt square‐pyramidal geometries and are bridged by two syn–syn carboxylate groups to form [Zn₂(COO)₂] secondary buildding units (SBUs). The SBUs are crosslinked by (m,m‐bpta)^4? ligands to produce a two‐dimensional grid‐like layer that exhibits a stair‐like structure along the a axis. Adjacent layers are linked by 4,4′‐bipy ligands to form a three‐dimensional network with a {4⁴.6¹⁰.8}{4⁴.6²} topology. In the solid state, the complex displays a strong photoluminescence and an excellent solvent stability. In addition, the luminescence sensing results indicate a highly selective and sensitive sensing for Fe³⁺ ions.