A new binuclear NiII complex with tetrafluorophthalate and 2,2′-bipyridine ligands: synthesis, crystal structure and magnetic properties

A new NiII compound, [Ni2(tfpa)2(bipy)2(H2O)4] (1) with tetrafluorophthalate (tfpa2−) and 2,2′-bipyridine (abbreviated as bipy) ligands, has been synthesized and structurally characterized. The single-crystal X-ray diffraction analysis reveals that the tfpa2− anions act as bis-monodentate linkers connecting NiII centers to form the dinuclear structure of 1. The dimeric units are stabilized by intramolecular π–π stacking and are further connected into a layer through O–HLO hydrogen bonding. Variable-temperature magnetic susceptibility data in the 10–200 K temperature range indicate weak ferromagnetic coupling between the two NiII ions.

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.

1,1′-Biphenyl-2,2′,5,5′-tetracarboxylic acid

In the title compound, C16H10O8or H4bptc, the dihedral angle between the planes of the phenyl rings is 51.90 (4)°. The asymmetric unit contains one half-molecule; complete molecules are generated by a twofold rotation axis. In the crystal, O—H...O and C—H...O hydrogen-bonding generate a two-dimensional supramolecular network. In addition, weak π–π interactions are also observed.

Exploring biphenyl-2,4,4′-tricarboxylic acid as a flexible building block for the hydrothermal self-assembly of diverse metal–organic and supramolecular networks

This contribution reports the hydrothermal self-assembly synthesis, characterization, thermal stability, structural and topological features, and luminescence or magnetic properties of a new series of nine coordination compounds.

Synthesis, crystal structure, photoluminescence property of a series of 3d-4f coordination supramolecular complexes

A series of 3d-4f heterobinuclear complexes were constructed by employing the 2,2'-bipy (2,2'-bipy=2,2'-bipyridine) ligand and corresponding metal ions (M(II)/Ln(III), M=Co(II), Cu(II) and Zn(II); Ln(III)=Nd(III), Sm(III), Eu(III) and Tb(III)). Elemental analyses, IR, UV-vis-NIR spectra, PXRD and single crystal X-ray diffraction analysis reveal that complexes 1-4, 5-8, and 9-12 are isomorphous, respectively. The zero-dimensional structures are further connected to 2D or 3D supramolecular network structures via extensive intermolecular hydrogen bonds. Luminescence studies for the heterobinuclear complexes containing Sm(III), Eu(III) and Tb(III) reveal that the chromophoric composed of Zn(II)/L may efficiently sensitize the luminescence of the rare earth cations which acts as an antenna, whereas the existence of Cu(II) leads to the quenching of the luminescence of Ln(III) ions.

A three-dimensional CdII coordination polymer constructed from 1,1'-biphenyl-2,2',5,5'-tetracarboxylate and 1,4-bis(1H-imidazol-1-yl)benzene ligands

The title coordination polymer, poly[[aqua(μ5-1,1'-biphenyl-2,2',5,5'-tetracarboxylato)bis[μ2-1,4-bis(1H-imidazol-1-yl)benzene]dicadmium(II)] dihydrate], {[Cd2(C16H6O8)(C12H10N4)2(H2O)]·2H2O}n, was crystallized from a mixture of 1,1'-biphenyl-2,2',5,5'-tetracarboxylic acid (H4bpta), 1,4-bis(1H-imidazol-1-yl)benzene (1,4-bib) and cadmium nitrate in water-dimethylformamide. The crystal structure consists of two crystallographically independent Cd(II) cations, with one of the Cd(II) cations possessing a slightly distorted pentagonal bipyramidal geometry. The second Cd(II) centre is coordinated by carboxylate O atoms and imidazole N atoms from two separate 1,4-bib ligands, displaying a distorted octahedral CdN2O4 geometry. The completely deprotonated bpta(4-) ligand, exhibiting a new coordination mode, bridges five Cd(II) cations to form one-dimensional chains via μ3-η(1):η(2):η(1):η(2) and μ2-η(1):η(1):η(0):η(0) modes, and these are further linked by 1,4-bib ligands to form a three-dimensional framework with a (4(2).6(4))(4.6(2))(4(3).6(5).7(2)) topology. The structure of the coordination polymer is reinforced by intermolecular hydrogen bonding between carboxylate O atoms, aqua ligands and crystallization water molecules. The solid-state photoluminescence properties were investigated and the complex might be a candidate for a thermally stable and solvent-resistant blue fluorescent material.

A series of mixed-ligand 2D and 3D coordination polymers assembled from a novel multifunctional pyridine-tricarboxylate building block: hydrothermal syntheses, structural and topological diversity, and magnetic and luminescent properties

4-(5-Carboxypyridin-2-yl)isophthalic acid (H₃L) was applied as a new principal building block for the self-assembly generation of mixed-ligand coordination polymers.

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

A series of isostructures based on 2,2′,4,4′-biphenyltetracarboxylic acid have been synthesized via solvothermal reaction, whereas magnetic studies reveal the polymers with sole syn–anti carboxylate bridges show different magnetic behaviors of uniform chains.

Synthesis, structure and properties of 2D lanthanide coordination polymers based on N-heterocyclic arylpolycarboxylate ligands

Eight 2D LCPs based on the N-heterocyclic arylpolycarboxylate ligands were prepared, and the luminescence and magnetic properties were studied.

Self-assembly and magnetic properties of Ni(ii)/Co(ii) coordination polymers based on 1,4-bis(imidazol-1-yl)benzene and varying biphenyltetracarboxylates

Five complexes of 1,4-bis(imidazol-1-yl)benzene, H₄bptas and cobalt/nickel are synthesized via solvothermal reaction; both of them have intriguing interpenetrated architectures.

Syntheses, crystal structures, photoluminescent/magnetic properties of four new coordination polymers based on 2,3′,4,5′-biphenyltetracarboxylic acid

Complex 1 is a (4,10)-connected deh1 net. Both complexes 2 and 4 exhibit (4,4)-connected mog moganite nets and novel (3,4,4)-connected networks respectively. Complex 3 is a 3D supermolecular net assembled by 1D anionic chains and cationic chains.

Five Cd(ii) coordination polymers based on 2,3′,5,5′-biphenyltetracarboxylic acid and N-donor coligands: syntheses, structures and fluorescent properties

Five Cd(ii) coordination polymers based on 2,3′,5,5′-biphenyltetracarboxylic acid and different bis(imidazole) ligands have been synthesized.