Search

The manipulation of structures and properties is a useful method in designing new materials. In this paper, two organic–inorganic hybrid compounds [(C6H15ClNO)2CoX4] (1, X = Cl; 2, X = Br) with reversible phase transition characteristics have been successfully synthesized. Systematic characterizations including crystal structure, thermal, dielectric, semiconducting, and photoluminescence properties were performed. Replacement of Cl with Br brings about not only the variation of the space group from C2/c to P21/c but also their properties. In comparison with Cl, the large Br atom could slow down the phase transition dynamics and give a larger thermal hysteresis of ∼25 K. Consequently, different shapes of switchable dielectric transition behavior are shown between 1 and 2. In addition, compound 2 has a smaller semiconducting band gap Eg than 1 (1.60 vs 1.65 eV). The results of this study will provide positive clues to manipulate the property of organic–inorganic hybrid compounds.

A series of novel 4f-3d crystalline porphyrinic compounds, {[Co(TPPS)]2[Ln(Histidine)(H2O)][Ln(H3O)3]}n·nH2O (Ln = Sm (1), Eu (2), Dy (3); TPPS = 5,10,15,20-tetra(4-sulfonatophenyl)porphyrinato) with TPPS and histidine as mixed ligands, have been prepared and characterized by single-crystal X-ray diffraction technique. Complexes 1–3 are isomorphous and characteristic of a three-dimensional (3D) framework with the lanthanide ions in two kinds of coordination geometries, i.e., eightfold square antiprism and ninefold monocapped square antiprism. The porphyrin macrocycles adopt a saddle-distorted nonplanar conformation with an embedded cobalt ion binding to four pyrrole nitrogen atoms. As revealed by the photoluminescence measurement, they exhibit blue emission. Variable-temperature magnetic susceptibility reveals that complexes 1–3 are antiferromagnetic. Their FTIR, CV, DPV, and UV/vis results are also studied in detail.

A new inorganic-organic hybrid complex based on well-defined Keggin-type polyoxometalates and copper-lutidine assemblies, namely, [Cu3(3,5-Lutidine)6(PW12O40)]n (1), has been obtained under hydrothermal conditions and characterized by elemental analysis and single crystal X-ray diffraction. The X-ray diffraction analysis reveals that compound 1 is three-dimensional (3D) supramolecular structure with ‘sql’ topological 2D layer. The photocatalytic experiments indicate that 1 exhibit good catalytic activity for photodegradation of Rhodamine B (RhB) with UV irradiation. The thermal stabilities and fluorescent properties of this complex have also been studied.

Two new Pb(II) coordination polymers, namely, [Pb(Hpydc)2]n (1), [Pb(Hpydc)2(H2O)]n·2n(H2O) (2) (H2pydc ​= ​2,5-pyridinedicarboxylic acid) have been prepared by the reaction of PbCl2 with pyridinedicarboxylic acid and fully characterized. Compound 1 contains ‘sql’ topological layers built from one-dimensional (1D) Pb-carboxylate infinite chains, and the layers are further packed into a 3D architecture by strong hydrogen bonds interactions. Compound 2 consists of 1D infinite chains containing Pb-dimers. The 3D supramolecular Pb(II) coordination complex of 2 is created by π – π interactions between the pyridine rings of the Hpydc ligands. In addition, solid-state properties of thermal stability and fluorescence for these crystalline materials are also presented. Time-dependent density functional theory (TDDFT) calculations reveal that the mechanism of the fluorescence emissions are dominantly resulted from the ligand-to-metal charge transfer (LMCT) and partial the intraligand π→π∗ and/or n→π∗ transitions for 1 and 2, which are in good agreement with their fluorescence spectra and crystal structure.

A new multifunctional mixed-valence copper(I/II) coordination polymer, {[CuCN][Cu(isonic)2]}n (1) (Hisonic = isonicotinic acid), was synthesized by treating isonicotinic acid and 5-amino-tetrazolate (Hatz = 5-amino-tetrazolate) with copper(II) salts under hydrothermal conditions, and characterized by elemental analysis, infrared spectroscopy, and single crystal X-ray diffraction, respectively. The X-ray diffraction analysis reveals that compound exhibit noncentrosymmetric polar packing arrangement. It is three-dimensional (3D) framework with (3,5)-connected ‘seh-3’ topological network constructed from metal organic framework {[Cu(isonic)2]}n and the inorganic linear chain{Cu(CN)}n subunits. A remarkable feature of 1 is the rhombic open channels that are occupied by a linear chain of {Cu(CN)}n. Impressively compound 1 displays not only a second harmonic generation (SHG) response, but also a ferroelectric behavior and magnetic properties.

Four new mercury coordination polymers were successfully synthesized under solvothermal conditions and characterized by elemental analysis, IR spectroscopy, thermal analysis, powder X-ray diffraction and single-crystal X-ray diffraction. In these complexes, the chemical valence of mercury is +2, except for complex 1 which is +1. 1 contains [Hg2]2+ metal–metal bonded cores which are bounded by atz− (Hatz = 5-amino-tetrazolate) ligands and features a two-dimensional (2D) uninodal 3-connected ‘hcb’ network. 2 exhibits a trinodal 3D (3,6)-connected ‘apo/alpha-PbO2’ topological net in which 2D [HgCl]nn+ inorganic cation layers are pillared by atz− ligands. In 3, the 2D [HgCl]nn+ cation layers are interconnected by atz− ligands, affording a trinodal 3D (3,6)-connected ‘flu/fluorite’ topological net. 4 is a 3D pillared-layer metal–organic framework based on mixed atz− and isonicotinic ligands, showing a binodal (4,6)-connected ‘fsc’ coordination network. In this work, 1 and 4 were synthesized from an in situ generated tetrazolate ligand, while 2 and 3 were prepared from a commercially available tetrazolate ligand. These results indicate that the final structures of the target complexes will highly depend on the synthetic conditions as well as the preparation methods. Moreover, the photoluminescence properties of these complexes were investigated. Impressively, the non-centrosymmetric complex 3 displays not only a second harmonic generation (SHG) response but also a ferroelectric behavior.

Three novel Ln–Hg complexes [Ln(H2O)2(μ-IA)3Hg3Br6]n (Ln = Pr (1), Nd (2), and Er (3); HIA is isonicotinic acid) are synthesized and characterized. They feature three-dimensional (3-D) motifs. Solid-state UV/vis diffuse reflectance spectroscopy found that their band gaps are 4.91, 4.59, and 2.68 eV. It is found that lanthanide ions could adjust the band structures of semiconductors. Their photoluminescence comes from their characteristic emissions of 1D2 → 3H4 of Pr3+, 7F7/2 → 4S3/2 and 4F3/2 → 4I9/2 of Nd3+, and 4I15/2 → 4F7/2 and 4I15/2 → 4S3/2 of Er3+. The CIE chromaticity coordinate is (x = 0.5726, y = 0.4206), (x = 0.7268, y = 0.2732), and (x = 0.2923, y = 0.4317). Their magnetization susceptibility totally obeys the Curie–Weiss equation with antiferromagnetic performances.

A novel tetranuclear lead-edta compound [Pb4(edta)(H2O)2(N3)4]n (1) (H4edta = ethylenediaminetetraacetic acid) has been synthesized by the reaction of PbF2 with H4edta and NaN3 mixed-ligands under hydrothermal conditions, and was characterized by elemental analysis, thermal analysis, luminescence, powder X-ray diffraction and single-crystal X-ray diffraction. The results of X-ray crystallographic analysis reveal that compound 1 is the first 3D Pb(II)-edta coordination polymer with a high ratio of lead. Remarkably, the edta4− ligand uses all its 10 donor atoms (8O ​+ ​2 ​N) coordinated to Pb(II) ions and formed a 2D layer. The 2D layers are further linked to a complex 3D coordination polymer by the inorganic chain [Pb5(N3)10]n. Time-dependent density functional theory (TDDFT) calculations reveal that the mechanism of the fluorescence emission is dominantly resulted from the ligand-to-metal charge transfer (LMCT) for 1, which is in good agreement with its fluorescence spectra and crystal structure. Optical absorption spectra indicate that 1 has wide optical band-gaps and can be probably used as wide optical band-gap semiconductor material.

Three Pb(II)-edta complexes, [Pb3(edta)(H2O)Cl2]n·(H2O)3n (1), [Pb5(edta)2(H2O)2X2]n·(H2O)2n (X = Cl (2), Br (3)) (H4edta = ethylenediaminetetraacetic acid) have been synthesized by the reaction of PbX2 and H4edta under hydrothermal conditions, and were characterized by elemental analysis, thermal analysis, luminescence, powder X-ray diffraction and single-crystal X-ray diffraction. The results of X-ray crystallographic analysis reveal that these complexes are the first bilayer two-dimensional (2D) Pb-edta coordination polymers with 1D channels. The bilayers of complexes 1, 2 and 3 are linked by [Pb2Cl4], [PbCl2] and [PbBr2] clusters with carboxylate groups respectively. They are 3D supramolecular structures which are resulted from different halogenide anions. The emission spectra of 1–3 are dominated by intense and broad emission bands which are resulted from the [PbX2] clusters. Optical absorption spectra indicate that theses complexes have wide optical band-gaps and can be probably used as wide optical band-gap semiconductor materials.

The organically-templated uranyl selenite, (H2en)[(UO2)(SeO3)(HSeO3)](NO3)·0.5H2O (1) (en = 1,2-ethylenediamine) was synthesized and characterized by elemental analyses, IR spectroscopy, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic system, space group Pbca, with a = 13.170(3) A, b = 11.055(2) A, c = 18.009(4) A, V = 2621.8(9) A3, M = 1316.19, Z = 4, Dcal = 3.334 g·cm–3, μ(Mo-Kα) = 17.998 mm–1, GOF = 1.059, R1 = 0.0263, wR2 = 0.0532 [I>2σ(I)]. The X-ray diffraction analysis reveals that compound 1 has a three-dimensional (3D) supramolecular structure. It contains negatively charged [UO2(HSeO3)(SeO3)]– inorganic anion layers and is balanced by [H2en]2+ cations and NO3– anions located in the interlayers. Furthermore, the photoluminescence properties of 1 were investigated.

Two new zinc compounds, [Zn2(mtz)(nic)2(OH)]n·0.5nH2O (1) and [Zn(phtz)(nic)]2n (2) (Hmtz = 5-methyltetrazole, Hphtz = 5-phenyltetrazole, Hnic = nicotinic acid), have been synthesized by a dual-ligand approach under solvothermal conditions. The compounds were characterized by single-crystal X-ray diffraction, elemental analysis, and infrared spectroscopy, respectively. The X-ray diffraction analysis reveals that both compounds exhibit a noncentrosymmetric polar packing arrangement. Compound 1 is a 3D framework constructed from the zigzag chain subunits of [Zn(nic)]+ with a 4-connected “irl” topology. Compound 2 possesses a 2D 4-connected ‘“sql” topology constructed from the linear chain subunit of [Zn(nic)]+, which are linked together with phtz– ligands. Impressively, both of the two compounds display second-harmonic generation response and ferroelectric behaviors. Furthermore, the photoluminescence of the compounds was also investigated.

A dysprosium-zinc porphyrin, [DyZn(TPPS)H3O]n (1) (TPPS = tetra(4-sulfonatophenyl)porphyrin), was prepared through solvothermal reactions and structurally characterized by single-crystal X-ray diffraction analyses. Complex 1 features a three-dimensional (3-D) porous open framework that is thermally stable up to 400 °C. Complex 1 displays a void space of 215 A3, occupying 9.2% of the unit cell volume. The fluorescence spectra reveal that it shows an emission band in the red region. The fluorescence lifetime is 39 µsec and the quantum yield is 1.7%. The cyclic voltammetry (CV) measurement revealed one quasi-reversible wave with E1/2 = 0.30 V. Copyright © 2015 John Wiley & Sons, Ltd.

A new type of ionic ferroelectric based on a chiral salen-type Schiff base erbium(III) complex (ErL) was synthesized by the reaction of erbium nitrate with the ligand N,N′-bis(3,5-dichlorosalicylidene)-(1S,2S)-1,2-cyclohexylenediamine (L). The structures of the ligand L and the complex ErL were determined by single-crystal X-ray diffraction. The results indicated that ErIII not only acts as central metal atom to coordinate with two Schiff base ligands, but also as Lewis acid catalyst to promote the partial decomposition of another salen-type Schiff base ligand. The central ErIII atom adopts an octacoordinate square antiprismatic arrangement with Λ absolute configuration, coordinating with all nitrogen and oxygen atoms of two ligands due to the influence of the strong electron-withdrawing group on the Schiff base ligand. The complex ErL exhibits good SHG and ferroelectric properties. The results provide a simple and effective approach to construct rare earth complexes coordinated with nitrogen and oxygen atoms of salen-type Schiff base ligands with technologically important properties such as SHG activity and ferroelectricity.

Three new compounds, {[Zn(tza)2(H2O)]·H2O}n (1), {[Mn(tza)2(Htza)2]·2H2O}n (2) and [Cd(tza)2]n (3), were obtained by reactions of 1H-Tetrazole-1-acetic (Htza) with corresponding metal salts, and characterized by elemental analysis, infrared spectroscopy, and single crystal X-ray diffraction, respectively. The X-ray diffraction analysis reveals that compound 1 is three-dimensional (3D) supramolecular structure with line chains. Compound 2 is three-dimensional (3D) supramolecular structure with Mn-carboxylate chains. Compound 3 is a 3D framework with (3,6)-connected ‘ant’ topological network. Furthermore, the photoluminescence of 1 and 3 and the magnetic properties of 2 have also been investigated.

A new type of multifunctional single ionic chiral dysprosium complex (DyL) was obtained by the reaction of Dy(NO3)3 and salen-type Schiff base ligand N,N′-bis(3,5-dichlorosalicylidene)-(1R,2R)-1,2-cyclohexylenediamine. In the synthesis reaction, Dy(III) was found not only to be the central metal to coordinate with two Schiff base ligands, but also the Lewis acid catalyst to promote the partial decomposition of salen-type Schiff base ligand. Complex DyL crystallizes in a chiral and polar space group P21. The central metal Dy(III) adopts eight-coordinated square antiprism geometry with Δ absolute configuration. Complex DyL exhibits good SHG and ferroelectric properties. The single-crystal sample of DyL displays an obvious ferroelectric behavior with a remnant polarization (Pr) of ca. 4.51 μC cm−2 and Ec of ca. 28.11 kV cm−1. The solid luminescent spectrum of DyL presents characteristic emission 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy(III).

A new three-dimensional(3D) coordination polymer, [Cu(atz)(isonic)]n (1) was synthesized hydrothermally from mixed-ligands of Hatz (Hatz = 5-amino-1H-tetrazole) and Hisonic (Hisonic = isonicotinic acid) and corresponding CuII salt. It was characterized by IR spectra, elemental and thermal analysis, structurally and magnetically characterized. In this compound, CuII ions are linked by μ3-atz bridges to give [{Cu2(μ3-atz)2}]2+ cationic layer. The cationic layers are further pillared by isonic ligand and resulted in 3D frameworks with unprecedented topological network. The variable temperature magnetic investigations indicate that compound 1 exhibits typical antiferromagnetic behaviors.

A new compound of [Cu8(Metz)9](OH)·xH2O (x≈3) (1) (Metz = 5-Methyltetrazole) has been prepared and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The crystal is of hexagonal, space group P63/m with a = b = 13.988(1) A, c = 16.309(2) A, α = β = 90°, γ = 120°, V = 2 763.5 (4) A3, Mr = 1327.13, D c = 1.595 g cm−3, Z = 2, F(000) = 1 316, μ = 3.076 mm−1, the final R = 0.0494 and wR = 0.1532 for 1,731 observed reflections (I > 2σ(I)). In this compound, the [(CuII)2(CuI)6(Metz)9]+ cationic clusters are connected together through CuI cations and Metz ligands and result in a three-dimensional framework. Remarkable, three-dimensional intersecting channels exist in it. The variable temperature magnetic investigations indicate that 1 exhibits typical antiferromagnetic behaviors. N2 gas adsorption measurements at 77 K showed that compound 1 possesses permanent porosities.

A new 3D coordination polymer, Mn2(atz)(isonic)(OH)(Cl)]n (1), was synthesized hydrothermally from mixed-ligands of Hatz (Hatz = 5-amino-tetrazolate) and Hisonic (Hisonic = isonicotinate) and corresponding metal salts. It was characterized by IR spectra, elemental and thermal analysis, single crystal and powder X-ray diffraction. Variable temperature magnetic investigations indicate that compound 1 exhibits typical antiferromagnetic behaviors.

A novel viologen(4,4′-bipyridinium)-based compound FeCl4(4,4′-diethyl-4,4′-bipyH) (1) (bipy = bipyridine), in which 4,4′-diethyl-4,4′-bipyH (MQ +) was generated in situ, is synthesized via the hydrothermal reaction and structurally characterized by single crystal X-ray diffraction. The crystal structure analysis reveals that the title compound features an isolated structure based on 4,4′-diethyl-4,4′-bipyH moieties and an iron atom terminally bound by four chlorine atoms. The 4,4′-diethyl-4,4′-bipyH moieties and (FeCl4)− anions are interconnected by hydrogen bonds to form a 3D supramolecular framework.

One couple of enantiomerically pure chiral Cu II Gd III coordination polymers [Cu(( S , S )-Salcy)Gd(NO 3 ) 3 ·CH 3 OH] n ( 1 ) and [Cu(( R , R )-Salcy)Gd(NO 3 ) 3 ·CH 3 OH] n ( 2 ) [( S , S )-Salcy or ( R , R )-Salcy = ( S , S )- or ( R , R )- N , N ′-(1,2-cyclohexanediylethylene) bis(3-ethoxysalicylideneiminato)dianion], were synthesized and structurally characterized. The self-assembly by intermolecular semicoordination of nitrate to copper(II) formed a one-dimensional zigzag chain structure. Magnetic property studies indicated that 1 and 2 exhibited very strong ferromagnetic interaction ( J = 6.285 and 7.408 cm −1 , respectively) between copper(II) and gadolinium(III) metal centers among the related complexes, although the dihedral angles (8.1° and 8.6°, respectively) of CuO 2 and GdO 2 are a little large.

A new compound of CuCl(QOA)(H2O) (1) [QOA = (8-quinolinyloxy)acetate] has been prepared and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The crystal is of orthorhombic, space group P212121 with a = 5.364(1) A, b = 13.876(3) A, c = 15.435(3) A, V = 1,148.8(4) A3, Mr = 319.19, Dc = 1.846 g cm−3, Z = 4, F(000) = 644, μ = 2.138 mm−1, flack parameter = 0.00(17), the final R = 0.0311 and wR = 0.0646 for 2,179 observed reflections (I > 2σ(I)). Compound 1 consists of one-dimensional helical chains deriving from CuCl(QOA)(H2O) units linked by hydrogen bonds and further extend into a 3D supramolecular structure through Van der Waals interactions, and it exhibits strong luminescent emission at room temperature.

A new Mn(II) complex, [Mn2(edta)(H2O)]n·nH2O (1) (H4edta = ethylenediaminetetraacetic acid) has been synthesized by the reaction of MnCl2·4H2O and H4edta under hydrothermal conditions, and was characterized by single-crystal X-ray diffraction study, variable temperature (1.8–300 K) magnetic measurement, and thermal gravity analysis. The result of X-ray crystallographic analysis reveals that complex 1 is the first two-dimensional (2D) Mn-edta coordination polymer with a grid-like (4,4)-topology, which is built from Mn-carboxylate chains and entirely deprotonated edta4− ligands with a maximum denticity. The variable temperature magnetic data indicate that complex 1 exhibits strong antiferromagnetic couplings.

In this paper, maleopimaric acid anhydride (MPA) has been synthesized by the Diels-Alder addition reaction between abietic acid and maleic anhydride. Single crystal X-ray diffraction analysis reveals that MPA crystallizes in the polar space groupP21and contains one MPA and one DMF (Dimethylformamide) molecule in the asymmetric unit. MPA is firstly found to be a new type of low-molecular-mass organic ferroelectric with the saturation spontaneous polarization (Ps) about 60.0-61.6μC·cm-2for single crystal samples, which is close to that of typical inorganic ferroelectric materials. MPA·DMF also shows second-order NLO property, with the second harmonic generation (SHG) responses approximately 0.5 times that of urea.

Two nickel coordination compounds with m-aminophenol-N,N,O-triacetic acid (H3L), [Ni(L)·(H2O)3]2·Ni(H2O)6·4.3H2O (1), and [Ni(L)·H2O]2·Ni(H2O)6 (2), were obtained under similar reaction conditions but at different synthesis temperature. Single crystal X-ray diffraction analysis reveals that both coordination compounds exhibit discrete dimeric entity structures and contain hexaaquanickel cations acting as counter-ions. Unit cell data for (1): triclinic, space group P-1, a = 7.9977(16), b = 10.475(2), c = 12.952(3) A and α = 107.36(3), β = 99.66(3), γ = 96.15(3)°; and for (2): monoclinic, space group P21/c, a = 13.524(3), b = 8.5703(17), c = 13.820(3) A and β = 95.25(3)°. In (1), O–H⋯O hydrogen bonds link the complex anions into a dimeric unit. But in (2), the dimeric unit is generated from two Ni centers bridged by two ligands. Extensive hydrogen bond interactions exist in both coordination compounds, and connect the complex anions, hexaaquanickel cations and/or water molecules, resulting in three-dimensional supramolecular structures. The compounds also have been characterized by elemental analysis, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), FT-IR and UV–Vis spectra. More coordinated water molecules of metal ion are substituted by N and/or O donors of ligand at higher reaction temperature.

The first example of isonicotinic acid compounds with infinite mercury halide chains, [HgCl2(C6NO2H5)]nn[HgCl2]n(C6NO2H5) (1), was synthesized through hydrothermal reactions and structurally characterized by X-ray single crystal diffraction. Compound 1 features a one-dimensional (1-D) motif, based on infinite 1-D [HgCl2(C6NO2H5)]n chains, neutral HgCl2 moieties and isolated isonicotinic acid molecules. The [HgCl2(C6NO2H5)]n chains, HgCl2 moieties and isonicotinic acid molecules are interlinked by hydrogen bonds and π-π interactions to give a two-dimensional supramolecular layer. Photoluminescent investigation reveals that the title compound exhibits a strong emission in blue region. The emission band is identified as the π -π* transitions of the isonicotinic acid moieties.

The title complex, (N,N′-dimethyl-4,4′-bipyridinium)[Cd2(μ 2-Cl)4Cl2]n (1), in which the N,N′-dimethyl-4,4′-bipyridinium was generated in situ, was synthesized via hydrothermal reaction. X-Ray diffraction analysis revealed that the structure of 1 consisted of MV 2+ (MV 2+ = N,N′-dimethyl-4,4′-bipyridinium) cationic moieties and infinite [Cd2(μ 2-Cl)4Cl2]n anionic chains. The cadmium atom was bound by one terminal chlorine atom and four μ 2-bridging chlorine atoms, yielding a slightly distorted triangular bipyramid. Photoluminescent investigation revealed that the complex displayed an emission in greenish blue region.

A novel trimetallic–isonicotinic acid complex [Zn0.5(H2O)]{(Hg2Cl5)[Eu(C6NO2H4)3(H2O)2]}(HgCl2)·H2O (1) has been synthesised and structurally characterised by single-crystal X-ray diffraction. Complex 1 features a novel 2-D {(Hg2Cl5)[Eu(C6NO2H4)3(H2O)2]} layer constructed from [Eu(C6NO2H4)3(H2O)2] chains interconnected by Hg2Cl5- linkers. The 2-D {(Hg2Cl5)[Eu(C6NO2H4)3(H2O)2]} layers are held together via hydrogen bonds and π–π interactions to yield a 3-D supramolecular framework with the lattice water molecules, the mercury chloride and the hydrated zinc ions located in the cavities.

Five Cd(II) coordination polymers with the in situ generated ligand 5-amino-tetrazolate (atz−) were prepared from the hydrothermal reactions of the corresponding Cd(II) salts, and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA) and single crystal X-ray diffraction. The results of X-ray crystallographic analysis revealed that compounds {[Cd5(atz)9]Cl}n·2nH2O (1) and {[Cd5(atz)9](SO4)0.5}n·2nH2O (3) are isostructural with the perfect Kagome layers bridged by [Cd2(μ4-atz)3] clusters to generate a three-dimensional (3D) rare lon (topological type symbol) topological network with a vertex symbol of 66. Its hexagonal channels are filled by Cl− or SO42− anions and water molecules. Compound [Cd5(atz)8(μ2-Cl)2]n·3nH2O (2) contains three different kinds of bridging modes of the atz− anion and is an intricate 3D polymer. It possesses a 5,6-connected btv topology with a vertex symbol of (47·62·8)2(410·65), which is rarely observed but only predicted by O’Keeffe in theory in coor...

A bimetallic 4f–3d tetranuclear complex {[Gd(H2O)4(μ2-C6NO2H5)2Gd(H2O)4](μ3-C6NO2H4)2(ZnCl3)2} · 2H2O · 2Cl (1) has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 is characterized by a tetranuclear Gd2Zn2 structure with the gadolinium and zinc atoms interconnected by isonicotinic acid ligands. The tetranuclear species of {[Gd(H2O)4(μ2-C6NO2H5)2Gd(H2O)4](μ3-C6NO2H4)2(ZnCl3)2} link to isolated chlorine ions and water molecules via π⋯π interactions and hydrogen bonds to yield a 3-D supramolecular framework. Photoluminescent investigation reveals that the title complex displays an emission in ultraviolet region. The solid-state diffuse reflectance spectra of 1 reveal the presence of a sharp optical gap of 3.66 eV.

Three new metal–organic frameworks, [Zn(atz)(nic)]n(1), [Zn(atz)(isonic)]n·nHisonic(2) and [Cd(atz)(isonic)]n(3) (Hnic=nicotinic acid, Hisonic=isonicotinic acid), have been firstly synthesized by employing mixed-ligand of pyridinecarboxylate with the in situ generated ligand of 5-amino-tetrazolate(atz−), and characterized by elemental analysis, IR spectroscopy, TGA and single crystal X-ray diffraction. The results revealed that 1 presents a two-dimensional (2D) “sql” topological network constructed from the linear chain subunit of Zn(nic)2 and atz− ligand. A remarkable feature of 2 is a 2-fold interpenetrated diamondoid network with free Hisonic molecules locating in the channels formed by the zigzag chain subunits of Zn(isonic)2. Complex 3 is a 3D non-interpenetrated pillared framework constructed from the double chain subunits of Cd–COO−–Cd. It possesses a rarely observed (4,6)-connected “fsc” topology. The thermal stabilities and fluorescent properties of the complexes were investigated. All of these complexes exhibited intense fluorescent emissions in the solid state at room temperature.

Two 3d/5d–4f metal complexes [DyL3(H2O)2]n(1.5nHgCl4) · 2nH2O (1) and [ EuL ′ 3 ( H 2 O ) 2 ] n (1.5nZnCl4) · nH2O (2), where L and L′ are isonicotinic acid and nicotinic acid, respectively, have been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffractions. Both complexes are characteristic of a one-dimensional polycationic chain-like structure. Photoluminescent investigation reveals that complex 1 displays emissions in violet, blue and yellow regions, and the violet emission is stronger than the blue and yellow ones. Complex 2 displays emissions in orange and red regions, and the emission are attributed to the characteristic emissions of 5D0 → 7FJ (J = 0, 1, 2, 3, 4) of Eu3+ ions. Optical absorption spectra reveal the presence of an optical gap of 3.31 and 3.86 eV for 1 and 2, respectively. The magnetic properties show that complex 1 exhibits antiferromagnetic-like interactions.

A 1-D metal-isonicotinato inorganic–organic hybrid complex [Gd(C6NO2H5)3(H2O)2]2 n · (nH5O2)(nZnCl5)(2nZnCl4) · (2nH2O) (1) has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 is a 1-D polycationic chain-like structure with unprecedented . Optical absorption spectra of 1 reveal the presence of an optical gap of 3.35 eV. Photoluminescence investigations reveal that the complex 2 display a strong blue-light fluorescent emission band.

A new heterometallic 4 f -3 d complex [Y(C 6 NO 2 H 5 ) 3 (H 2 O) 2 ] n (1.5 n ZnCl 4 ). n H 2 O( 1 ), was synthesized via a hydrothermal reaction and structurally characterized. Complex 1 crystallized in the monoclinic system with space group P 2 1 / c : a =0.94847(9) nm, b =2.0947(2) nm, c =1.6001(2) nm, β=104.467(2)°, V -3.0781(5) nm 3 , M r =823.04, D c =1.776 g/cm 3 , S =1.009, μ(Mo K α)=3.603 mm −1 , F (000)=1632, R =0.0787, and wR =0.2273. Complex 1 , with four formula units in a cell, was characteristic of a one-dimensional polycationic chain-like structure. Photolumincscent investigation showed that the title complex displayed a strong emission in the blue region, which was attributed to the intraligand π-π * transition of the nicotinic ligands. Optical absorption spectrum of complex 1 revealed the presence of a wide optical bandgap of 4.17 eV.

A novel heterometallic metal-isonicotinic acid inorganic-organic hybrid complex [Zn0.5(H2O)]{(Hg2Cl5)- [Er(C6NO2H4)3(H2O)2]}(HgCl2)·0.5CH3OH·0.5H2O (1) has been successfully synthesized via a hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 crystallizes in the space group C2/c of the monoclinic system with eight formula units in a cell: a=34.165(4) A, b=9.4692(8) A, c=24.575(3) A, β =115.090(5)°, V=7200(1) A3, C18.50H21Cl7ErHg3N3O10Zn0.50, Mr=1495.25, Dc=2.759 g/cm3, T=293(2) K, µ(Mo Kα) =15.954 mm−1, F(000) =5400 and R1/wR2=0.0561/0.0909 for 3157 observed reflections [I>2δ(I)] and 6468 unique reflections. Complex 1 is characteristic of a novel 2D {(Hg2Cl5)[Er(C6NO2H4)3(H2O)2]} layered structure constructed from the [Er(C6NO2H4)3(H2O)2] chains interconnected by the Hg2Cl5− linkers. The 2D {(Hg2Cl5)[Er(C6NO2H4)3(H2O)2]} layers, mercury chloride and the lattice water molecules are held together via hydrogen bonds to form a three-dimensional framework with the methanol molecules and the hydrated zinc ions located in the cavities. The magnetic properties show that complex 1 exhibits antiferromagnetic-like interactions.

A novel bimetallic 4f–3d complex [Er(C 6 H 5 NO 2 ) 3 (H 2 O) 2 ] n (1.5 n ZnCl 4 ) · (2 n H 2 O) ( 1 ) has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. Complex 1 is characteristic of a novel one-dimensional polycationic chain-like structure. Photoluminescent investigation reveals that the title complex displays interesting emissions in green and red regions. The luminescence spectra show that the green emission is stronger than the red emission. The green and red emission bands are attributed to the characteristic emissions of 4 F 7/2 , 2 H 11/2 , 4 S 3/2 , 4 F 9/2 → 4 I 15/2 of Er 3+ ions. Optical absorption spectra of 1 reveal the presence of an optical gap of 3.85 eV.

A new heterometallic 4f-3d inorganic-organic metal-nicotinic acid complex [Gd(C6NO2H5)3(H2O)2] n(1.5 nZnCl4) nH2O, (1), has been synthesised via hydrothermal reaction and structurally characterised. Complex 1 crystallises in the space group P21/ c of the monoclinic system with four formula units in a cell: a = 9.524(2), b = 20.888(4), c = 16.078(3) Å β = 104.745(2)°, V= 3093.2(9) Å3, C18H21Cl6GdN3O9Zn1.50, M r=891.38 g/mol, D c= 1.914 g/cm3, S = 0.997, μ(MoKα) = 3.844 mm1, F(000) = 1732, R = 0.0493 and wR = 0.1350. Complex 1 is characteristic of a one-dimensional polycationic chain-like structure. Photoluminescent investigation shows that the title complex displays strong emission in the blue region, which is attributed to the intraligand π–π* transition of nicotinic ligands. Optical absorption spectra of 1 reveal the presence of a wide optical bandgap of 3.73 eV.

An isomorphous series of three novel lanthanide coordination polymers [Ln(PCPA)3(glycol)] n , [where, Ln = La(1); Nd(2); Gd(3); PCPA = p-chlorophenoxyacetate] have been synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectra, TG analysis, fluorescence spectra and single crystal X-ray diffraction analysis. The results reveal that all of them form a chain-like one-dimensional structure. Photoluminescent properties for the complexes are also reported.

Three novel three-dimensional metal−organic frameworks [Ln2(tdc)3(H2O)4]n, Ln = Dy(1), Ho(2), Er(3) (H2tdc = thiophene-2,5-dicarboxylic acid) have been synthesized and characterized by single crystal X-ray diffraction (XRD), powder XRD and IR spectra. X-ray crystallography reveals that the three complexes are isostructural and exhibit an unprecedented (4,5)-connected (42·64)(42·67·8) topology, in which the lanthanide ions act as unusual 5-connected nodes. The thermal stability and UV–vis absorption spectra of the title complexes have also been studied.

Hydrothermal reactions of Gd(III) nitrate with N , N , N ′, N ′-tetramethylenephosphono-1,4-diaminobutane, (H 2 O 3 PCH 2 ) 2 N–(CH 2 ) 4 –N(CH 2 PO 3 H 2 ) 2 (H 8 L), afforded a novel Gd(III) phosphonate, namely, Gd[(O 3 PCH 2 )(HO 3 PCH 2 )N(H)(CH 2 ) 4 N(H)(CH 2 PO 3 H) 2 ] · 2H 2 O, [Gd(H 5 L)] · 2H 2 O. Its structure was established by a single-crystal X-ray diffraction study. In this compound, the Gd(III) ion is coordinated by eight phoshonate oxygen atoms from five different phosphonate groups, which belong to five different phosphonic ligands. Each Gd atom is connected with its neighboring Gd atoms by two phosphonate oxygens, forming a gadolinium phosphonate slab along the a -axis. Such slabs are bridged by tetraphosphonate H 5 L anions, resulting in a 〈0 1 1〉 layer with the butane groups toward the interlayer space. These layers are further interlinked by strong hydrogen bonds formed by uncoordinated phosphonate oxygens into a 3D supermolecular structure. Luminescent studies indicate that this compound exhibits a broad blue fluorescent emission band at 441 nm.

A novel iron porphyrin [FeTCPP] n [TCPP = meso-tetra(4-carboxyphenyl)porphyrin] has been synthesised via a hydrothermal reaction and structurally characterised. It has a two-dimensional structure and is thermally stable up to 320°C. UV–Vis, FT–IR and fluorescence data are also reported. Porphyrins have interesting roles in nature such as in green leaves and red blood cells, as well as applications in medicine, catalysis, optics, conductive materials, magnetism and solar energy conversion.

In the title compound, [Pb(C6H4NO2)(N3)(H2O)]n, the Pb ion is seven-coordinated by three N atoms from three azide ligands, two O atoms from two isonicotinate (inic) ligands and two O atoms from two coordinated water mol­ecules, forming a distorted monocapped triangular prismatic coordination geometry. Each azide ligand bridges three PbII ions in a μ1,1,3 coordination mode to form a two-dimensional three-connected 63 topology network extending in the bc plane. The carboxyl­ate group of the inic unit and the aqua ligand act as coligands to bridge PbII ions. Adjacent two-dimensional layers are connected by hydrogen-bonding inter­actions between the isonicotinate N atom and the water mol­ecule, resulting in an extended three-dimensional network. The title complex is the first reported coordination polymer involving a p-block metal, an azide and a carboxyl­ate.

A novel viologen(4,4′-bipyridinium)-based complex ZnCl 3 (4-methyl-4,4′-bipyridinium) ( 1 ), in which the 4-methyl-4,4′-bipyridinium (MQ + ) was generated in situ, has been synthesized via hydrothermal reaction and structurally characterized by single-crystal X-ray diffraction. The title complex features an isolated structure, based on the MQ + ligand coordinating to a zinc atom that is further terminally bound by three chlorine atoms. Photoluminescence investigation reveals a strong emission in blue region, which may originate from π → π ∗ charge-transfer interaction of the MQ + ligand.

A novel trinuclear V V/IV/V complex, [VO 2 ( phen )(SO 4 )(H 2 O)] 2 [VO( phen )(H 2 O)]} ( 1 ), containing linear mono-μ-oxo [V 3 O 5 ] 4+ core was prepared and characterized by single-crystal X-ray diffraction. Complex 1 represents the first mixed-valence polynuclear vanadium complex with linear mono-μ-oxo-vanadium/vanadyl core. Furthermore, the study of the EPR and electronic spectrum of complex 1 show that it is a Class II species according to the Robin and Day classification scheme.

The asymmetric unit of the title compound, [CuCl(C12H8N2)2]I·H2O, consists of a [CuCl(phen)2]+ cation (phen = l,10-phenanthroline), an iodide anion and a water mol­ecule of crystallization. The coordination geometry around the CuII atom is distorted trigonal-bipyramidal. The crystal packing is stabilized by inter­molecular π–π stacking inter­actions and C—H⋯O, O—H⋯Cl and O—H⋯I hydrogen bonds.

The title compound, [CuIIAgI(SCN)3(NH3)4]n, consists of two single chains of CuN6 Jahn–Teller-distorted octa­hedra and AgS4 tetra­hedra connected by thio­cyanate groups. Both metal atoms are located on twofold rotation axes. The two single chains are connected, forming a double chain along the a axis. Adjacent double chains are linked into a three-dimensional network by N—H⋯N hydrogen bonds.

The repeat unit of the title compound, [U(C6H5NO2)(C2O4)O2]n, consists of a uranyl unit, an oxalate anion and a zwitterionic isonicotinic acid. The U atoms and the isonicotinic acid ligand are located on a crystallographic twofold rotation axis, while the oxalate lies on an inversion centre. Each UO2 unit is coordinated by two oxalate ligands and one isonicotinic ligand. In the crystal structure, the UO8 hexa­gonal bipyramids are connected by oxalate groups to form chains, and adjacent chains are linked into two-dimensional sheets by bifurcated N—H⋯O hydrogen bonds.

A series of mononuclear lanthanide complexes with chiral Schiff base ligands [Ln(FTA)(3)L] [Ln = Dy(1), Sm(2), Eu(3), Gd(4), and Tb(5), L = (S,S)-2,2'-Bis(4-benzyl-2-oxazoline)] were synthesized and characterized. Among these complexes, complex 1 represents the first example of mononuclear lanthanide complexes displaying single-ion magnet behavior and ferroelectricity.

The asymmetric unit of the title complex, [CdCl(2)(C(14)H(12)N(4)O(2)S)(2)](n), consists of one Cd(II) ion located on the crystallographic inversion centre, one 4-benzoyl-1-isonicotinoylthiosemicarbazide ligand and one chloride ligand. The central Cd(II) ion adopts a distorted octahedral coordination geometry formed by two pyridyl N atoms of two ligands, two S atoms of two other ligands and two chloride ligands. The thiosemicarbazide ligands act as bridges, linking the metal ions into a two-dimensional layered structure parallel to the bc plane. Intermolecular N-H...O hydrogen bonds and C-H...pi interactions exist between adjacent layers.