Ladder-like Chain Research Articles

Fluorescent sensing and electrocatalytic properties of three Zn(II)/Co(II) coordination complexes containing two different dicarboxylates and two various bis(pyridyl)-bis(amide) ligands

Three new transition metal(II) coordination complexes constructed from two different dicarboxylates (1,3-H2BDC = 1,3-benzenedicarboxylic acid, 1,4-H2NDC = 1,4-naphthalenedicarboxylic acid) and two bis(pyridyl)-bis(amide) ligands (3-bpcd = N,N′-bis(3-pyridyl)cyclohexane-1,4-dicarboxamide, 3-bpod = N,N′-bis(3-pyridyl)octandiamide), [Zn(1,3-BDC)(3-bpcd)0.5(H2O)]·H2O (1), [Zn(1,3-BDC)(3-bpod)0.5(H2O)] (2) and [Co(1,4-NDC)(3-bpod)1.5(H2O)] (3) have been synthesized in the hydrothermal environments and structurally characterized by IR, TG and single crystal X-ray diffraction. Complexes 1 and 2 possess the similar 1D ladder-like chain based on [Zn(1,3-BDC)]n zigzag chain and the bidentate ligands 3-bpcd/or 3-bpod. Complex 3 shows a 2D layered structure with a 5-connected {410} topology, which consists of 1D linear [Co(1,4-NDC)]n chain and [Co(3-bpod)1.5]n chain with alternating arrangement of 3-bpod ligands and Co2(3-bpod)2 dinuclear loops. The adjacent 1D chains for 1–2 or the 2D layers for 3 are further extended into 2D or 3D supramolecular frameworks through the hydrogen bonding interactions. Additionally, the solid state fluorescent properties for the title complexes 1–3, the fluorescent sensing behaviors of complexes 1–2 and the electrochemical behaviour of complex 3 have been investigated.

1D ladder-like chain and 3-fold Borromean entanglement of silver(I) coordination polymers with different metal salts

Two Ag(I) coordination polymers, namely [Ag(L)(p-bdc)0.5]n (1) and [Ag(L)(p-bdc)0.5·2H2O]n (2) (L=1,3-bis(2-methylbenzimidazol-1-ylmethyl)benzene, p-H2bdc=1,4-benzenedicarboxylic acid) have been synthesized under hydrothermal conditions by different silver(I) salt. Complex 1 is a 2D Borromean entanglement involving 3-fold (6,3) honeycomb networks. Nevertheless, complex 2 display a 1D ladder-like chain structure. Both complexes are ultimately extended into 3D supramolecular frameworks via Ag···O interactions and π···π interactions. The fluorescence and catalytic activities of two complexes for the degradation of methyl orange by sodium persulfate were addressed.

Design and syntheses of hybrid metal–organic materials based on K3[M(C2O4)3]·3H2O [M(III)=Fe, Al, Cr] metallotectons

By using K3[M(C2O4)3]·3H2O [M(III)=Fe, Al, Cr] (C2O42−=oxalate) metallotectons as the starting material, we have synthesized eight novel complexes with formulas [{Fe(C2O4)2(H2O)2}2]·(H–L1)2·H2O 1, [Fe(C2O4)Cl2]·(H2–L2)0.5·(L2)0.5·H2O 2, [{Fe(C2O4)1.5Cl2}2]·(H–L3)43, [Fe2(C2O4)Cl8]·(H2–L4)2·2H2O 4, K[Al(C2O4)3]·(H2–L5)·2H2O 5, K[Al(C2O4)3]·(H–L6)2·2H2O 6, K[Cr(C2O4)3]·2H2O 7, Na[Fe(C2O4)3]·(H–L6)2·2H2O 8 (with L1=4-dimethylaminopyridine, L2=2,3,5,6-tetramethylpyrazine, L3=2-aminobenzimidazole, L4=1,4-bis-(1H-imidazol-1-yl)benzene, L5=1,4-bis((2-methylimidazol-1-yl)methyl)benzene, L6=2-methylbenzimidazole). Their structures have been determined by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra and thermogravimetric analyses. Compound 3 is a 2D H-bonded supramolecular architecture. Others are 3D supramolecular structures. Compound 1 shows a [Fe(C2O4)2(H2O)2]− unit and 3D antionic H-bonded framework. Compound 2 features a [Fe(C2O4)Cl2]- anion and 1D iron-oxalate-iron chain. Compound 3 features a [Fe2(C2O4)3Cl4]4− unit. Compound 4 features distinct [Fe2(C2O4)Cl8]4− units, which are mutual linked by water molecules to generated a 2D H-bonded network. Compound 5 features infinite ladder-like chains constructed by [Al(C2O4)3]3− units and K+ cations. The 1D chains are further extended into 3D antionic H-bonded framework through O–H···O H-bonds. Compounds 6–8 show 2D [KAl(C2O4)3]2− layer, [KCr(C2O4)3]2− layer and [NaFe(C2O4)3]2− layer, respectively.

Homobimetallic zinc(II) dithiocarbamates: synthesis, characterization and in vivo antihyperglycemic activity

This article presents structural characteristic and in vivo antihyperglycemic activities of three new homobimetallic Zn(II) dithiocarbamates (1–3) with general formula [ZnL2]2, where L is 4-(3-methoxyphenyl)piperazine-1-carbodithioate (1), 4-(4-methoxyphenyl)piperazine-1-carbodithioate (2) and 4-benzhydrylpiperazine-1-carbodithiaoate (3). These complexes have been characterized by elemental analysis, FT-IR, multinuclear NMR (1H and 13C), and X-ray single crystal analysis. The latter technique has confirmed the homobimetallic nature of 1 and 2 in which Zn ions are linked via sulfurs to form a four-membered ring Zn2S2. Non-covalent intermolecular interactions give a supramolecular ladder-like zigzag chain (1) and layered structure (2). The antihyperglycemic activities revealed that the blood glucose lowering ability follows the trend: glibenclamide (83.0 mg dL−1) > 3 (97.6 mg dL−1) > 2 (100.4 mg dL−1) > 1 (141.4 mg dL−1).

Two 3d-4f double helical chains including [Dy2M2]n (M = Ni(II) and Co(II)) cores exhibiting slow magnetic relaxation.

Two new 3d-4f heterometallic 1D chains of formulae {[Dy2M2L4(NO3)(H2O)3][Dy2M2L4(NO3)(CH3COO)(H2O)2]·NO3·12H2O·2C2H5OH}n [M = Ni (); Co ()] have been prepared using the multidentate ligand 2-{[(2-hydroxy-3-methoxyphenyl)methylidene]amino}benzoic acid (H2L), which has NO and OO' chelating pockets that are able to selectively encapsulate Ln(III) and transition metal ions, respectively. Crystal structure analyses reveal that the two complexes are isostructural and display one-dimensional ladder-like double helical chain structures, in which the two single helical chains {[Dy2M2L4(NO3)(H2O)3](+)} and {Dy2M2L4(NO3)(CH3COO)(H2O)2} (M = Ni(), Co()) both run along the c-axis and have opposite chirality. Complexes and represent the first example of 3d-4f double-chain frameworks in which the compositions of the two individual chains are different. Variable temperature dc magnetic susceptibility studies reveal different strengths of ferromagnetic interactions between the magnetic centers in and , which is mainly attributed to the different metal centers and finally results in the distinctive magnetic dynamic behaviors.

Anion- and temperature-dependent assembly, crystal structures and luminescence properties of six new Cd(ii) coordination polymers based on 2,3,5,6-tetrakis(2-pyridyl)pyrazine

Solvothermal reactions of 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) and sodium azide with different cadmium salts including CdCl2·2.5H2O, Cd(NO3)2 and Cd(CH3COO)2·2H2O at 80 °C produce three new coordination polymers, namely, {[Cd2(N3)2(tppz)Cl2]·2H2O}n (1), [Cd2(N3)2(tppz)(NO3)2]n (2) and {[Cd2(N3)2(tppz)(CH3COO)2]·2H2O}n (3), respectively. Single-crystal X-ray diffraction analysis reveals that the anions of the Cd(II) salts all participate in coordination in compounds 1–3. Compound 1 features an infinite one-dimensional (1D) chain with loops-and-rods topology, compound 2 exhibits a 1D ladder-like chain, while compound 3 possesses a 2D honeycomb-like network structure with (6,3) topology. The low-dimensional structures of compounds 1–3 are further stabilized by diverse supramolecular interactions such as hydrogen bonds and π⋯π stacking. Interestingly, when the temperature is increased to 100 °C, similar reactions of tppz and sodium azide ligands with CdCl2·2.5H2O, Cd(NO3)2 and Cd(CH3COO)2·2H2O lead to three other novel 3D Cd(II) coordination polymers formulated as [Cd3(N3)6(tppz)]n (4), {[Cd2(N3)2(tppz)(NO3)2]·MeOH}n (5) and [Cd4(N3)6(tppz)(CH3COO)2]n (6), respectively. The anions of the Cd(II) salts again take part in coordination in compounds 5 and 6 but disappear in the final structure of 4. Compound 4 displays a rare sxd-type 3D framework with the Schlafli symbol of (33·46·55·6) if each V-shaped trinuclear [Cd3(μ1,1-N3)4] secondary building unit (SBU) is regarded as a 6-connected node. In compound 5, both the Cd1 and Cd2 atoms serve as 3-connected nodes to construct an uncommon binodal (3,3)-connected 3D framework with (6·102)(62·10) topology. Compound 6 contains another type of V-shaped trinuclear [Cd3(μ1,1-N3)2(μ3-CH3COO)] SBU, which acts as a 7-connected node to fabricate a unique uninodal 7-connected 3D framework with a completely new topology of (36·42·510·63). The present results reveal that both anions and temperature play essential roles in the structural and topological diversity of such six new Cd(II) coordination polymers. Moreover, the IR spectra, thermogravimetric analysis curves, and solid-state luminescence properties of all the compounds have been also investigated. Compared with the free tppz ligand, compounds 1–6 exhibit superior luminescence properties with largely enhanced emission, indicating that they may be good candidates for optical materials.

Three ion–pair complexes containing bis(maleonitriledithiolate)copper(II) anion and substituted 2-aminopyridinium cations: Syntheses, crystal structures, and magnetic properties

Three new ion–pair complexes, [2-ClBz-2′-NH2Py]2[Cu(mnt)2](1), [2-Cl-4-ClBz-2-NH2Py]2[Cu(mnt)2](2) and [2-Cl-4-BrBz-2′-NH2Py]2[Cu(mnt)2]·C2H5OH(3) ([2-Cl-4-RBz-2′-NH2Py]+ = 1-(2′-chloro-4′-Rbenzyl)-2-aminopyridinium, R = H, Cl, Br; mnt2− = maleonitriledithiolate), were synthesized and characterized by elemental analyses, IR, UV–visible, single crystal X−ray diffraction and magnetic measurements. Both 1 and 2 crystallize in the monoclinic space group P2(1)/c, and the [Cu(mnt)2]2− anions and the cations form a 1D network structure through the N–H⋅⋅⋅N hydrogen bonds. While the anions in 3 form a ladder-like chain through the C–H⋅⋅⋅N interactions between the [Cu(mnt)2]2− anions and CH3CH2OH molecules. Some weak interactions such as π⋅⋅⋅π, Cu⋅⋅⋅N, Cl⋅⋅⋅C, and C–H⋅⋅⋅Cl, O–H⋅⋅⋅Cl, C–H⋅⋅⋅S, N–H⋅⋅⋅O, N–H⋅⋅⋅N and C–H⋅⋅⋅N hydrogen bonds in three molecular solids generate further a 3D network structure. The magnetic measurement reveals that 1 shows a very weak ferromagnetic interaction, and 2 exhibits a transition from ferromagnetic to antiferromagnetic coupling about 15 K, while 3 shows an antiferromagnetic coupling feature with θ = −12.51 K when the temperature is lowered.

Characterization and cytotoxic property of a ladder-like polymeric silver(I) complex derived from 3-aminopyrazine-2-carboxylic acid

A novel ladder-like polymeric silver(I) complex, [Ag2L2] n •2nH2O, where L is 3-aminopyrazine- 2-carboxylate, was obtained by the reaction of 3-aminopyrazine-2-carboxylic acid and silver oxide in aqueous ammonia. The complex was characterized by elemental analysis, IR spectra and single crystal X-ray determination. The smallest repeat unit contains a [Ag2L2] moiety and two water molecules. The Ag•••Ag distance is 3.176(1) A. Each Ag atom is in a Y-shaped coordination, with one carboxylate O and two pyrazine N atoms from two ligands. In the crystal structure of the complex, the dinuclear silver moieties are linked through 3-aminopyrazine-2-carboxylate ligands, to form 1D ladder-like chain along the b axis. The water molecules are linked to the silver chain through hydrogen bonds. There are π•••π interactions between the chains. The complex showed effective cytotoxic property on human lung cancer cell line A549.

Metal–organic hybrid materials built with tetrachlorophthalate acid and different N-donor coligands: Structure diversity and photoluminescence

Eight new metal–organic hybrid materials, namely {Cd(Tcph)(4,4′-bipy)1/2} (1), {[Cd2(Tcph)2(1,4-bimb)1/2(H2O)4]·H2O} (2), {Cd2(Tcph)2(1,4-bmimb)1/2(H2O)4} (3), {Cd(Tcph)(1,2-bmimb)} (4), {Cu(Tcph)(1,4-bimb)(H2O)} (5), {[Co(Tcph)(1,4-bimb)1/2(H2O)3]·(H2O)} (6), {Zn(Tcph)(1,2-bimb)} (7), {Cu2(Tcph)2(1,2-bimb)(H2O)4} (8), where Tcph=tetrachlorophthalate acid, 4,4′-bipy=4,4′-bipyridine, 1,4-bimb=1,4-bis(imidazol-1-ylmethyl)benzene, 1,4-bmimb=1,4-bis(2-methylimidazol-1-ylmethyl)benzene, 1,2-bimb=1,2-bis(imidazol-1-ylmethyl)-benzene, 1,2-bmimb=1,2-bis(2-methylimidazol-1-ylmethyl)benzene, have been synthesized and characterized. Their structures are determined by single crystal X-ray diffraction and further characterized by infrared spectra (IR) and thermogravimetric (TG) analyses. Complex 1, 4 and 7 display 2D layer structures. 1 possesses two-dimensional sheet containing an unusual [Cd(Tcph)] chains linked by 4,4′-bipy co-ligand, while 4 and 7 hold the similar 4-connected 44-sql nets. Complex 2 and 3 feature a similar three dimensional (3D) internal compensation structure with a topology of {42·63·8}2{63}. 5 is a novel 2-fold self-penetrating 3D network with 4-coordinated 65·8–CdSO4 subnets. The ladder-like chains of 6 are further connected through O–H···O interactions to yield a 3D supramolecular structure. 8 is a discrete tetranuclear complex. The thermal stabilities of 1–8 and the luminescent properties of 1–4 and 7 in the solid state are also discussed.

Diverse topologies of three cobalt(II) coordination polymers constructed from flexible bis(benzimidazole) and dicarboxylate ligands

Three cobalt(II) coordination polymers {[Co(L1)(nda)(H2O)2]·2H2O} n (1), [Co(L2)(tbi)(H2O)] n (2) and [Co(L2)(bpdc)(H2O)] n (3) (L1 = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)-2-propanol, L2 = 1,3-bis(benzimidazol-1-yl)-2-propanol, H2nda = 2,6-naphthalenedicarboxylic acid, H2tbi = 5-tert-butyl isophthalic acid and H2bpdc = 4,4′-biphenyldicarboxylic acid) were synthesized and characterized by physicochemical and spectroscopic methods. Complex 1 exhibits a 1D loop-like structure, which is further extended into a 3D 3,3,4T31 network through two O–H···O hydrogen bonding interactions. Complex 2 displays a 1D ladder-like chain, arranged into a 2D supramolecular network with 3,3,4L34 topology via classical O–H···O hydrogen bonding interactions, whereas complex 3 features a 2D 3,4L13 layer structure and further assembles into a 3D framework with a twofold interpenetrating sqc65 topology through O–H···O hydrogen bonding interactions. The fluorescence and catalytic properties of these complexes for the degradation of Congo red in a Fenton-like process have been investigated.

Sm3S3BO3: The First Sulfide Borate without S-O and B-S Bonds.

An unprecedented quaternary sulfide borate, Sm3S3BO3 (1), was obtained via a high-temperature solid-state synthesis method. It crystallizes in the triclinic space group P1̅, and its 3D structure features a 2D (Sm2S2)∞ wrinkled layer and a 1D (SmS)∞ ladderlike chain bridged by trigonal-planar (BO3)(3-) through Sm-O bonds, demonstrating the first sulfide borate without S-O and B-S bonds. Its optical energy gap is measured to be around 2.5 eV and verified by electronic structure calculation.

In situ construction of four copper(I) cyanide coordination polymers: crystal structures, fluorescence and catalytic properties

Four Cu(I) cyanide coordination polymers, namely [Cu(L1)(CN)] n (1), [Cu2(L2)(CN)2] n (2), [Cu2(L3)(CN)2] n (3) and [Cu2(L4)(CN)2] n (4) (L1 = 4,4′-bis(1,2,4-triazolyl-1-yl)-biphenyl, L2 = 1,4-bis(5,6-dimethylbenzimidazole)butane, L3 = 1,3-bis(2-methylbenzimidazole)propane, L4 = 1,5-bis(5,6-dimethylbenzimidazole)pentane), were synthesized and structurally characterized by X-ray single-crystal diffraction. The cyanide anions in these complexes were generated in situ by cleavage of the C–C bond of acetonitrile under hydrothermal conditions. Complex 1 possesses a 1D infinite ladder-like chain structure, while complexes 2, 3 and 4 exhibit similar 2D (6,3) networks. Both 3 and 4 are further extended into 3D supramolecular frameworks by C–H···π stacking interactions. The fluorescence properties of the complexes and their catalytic activities for the degradation of Congo red azo dye in a Fenton-like process were investigated.

Syntheses, structures and properties of five Cu(II) coordination polymers derived from semi-rigid bis-pyridyl-bis-amide and nitro-substituted aromatic carboxylates

Five new coordination polymers (CPs) based on two semi-rigid bis-pyridyl-bis-amide ligands and different nitro-substituted carboxylates, namely [Cu(3,5-dnb)(μ2-OH)] (1), [Cu4(4-bpcc)2(3,5-dnb)6(μ3-OH)2(H2O)2] (2), [Cu(4-bpcc)2(5-Hnip)2] (3), [Cu3(4-bpcc)(5-nip)2(5-Hnip)(μ3-OH)(H2O)]·4H2O (4), and [Cu(3-bpcc)(5-nip)]·2H2O (5) (3,5-Hdnb=3,5-dinitrobenzoic acid, 5-H2nip=5-nitroisophthalic acid, 4-bpcc=N,N′-bis(4-pyridinecarboxamide)-1,2-cyclohexane, and 3-bpcc=N,N′-bis(3-pyridinecarboxamide)-1,2-cyclohexane), were synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, TG analysis and powder X-ray diffraction. Complex 1 shows a 3D framework, which features a (3,5)-connected topology with the Schläfli symbol of {3·72}{32·75·83}. Complex 2 displays a 3D supramolecular structure based on the tetranuclear [Cu4(3,5-dnb)6(μ3-OH)2] clusters, while complex 3 presents a 3D supramolecular architecture with mononuclear Cu(II) subunits. Complex 4 was obtained at a higher pH value than that in 3, which exhibits a uninodal 5-connected 3D bnn framework constructed from 1D ladder-like chains and μ2-bridging 4-bpcc ligands. Complex 5 is a 2D (4,4)-network based on a 1D [Cu(3-bpcc)]n meso-helixe and a 1D [Cu(5-nip)]n zigzag chains. The bis-pyridyl-bis-amide ligands and nitro-substituted carboxylates, as well as pH show great influence on the formation and various structures of the title complexes. The fluorescent and electrochemical properties of the title complexes were investigated.

A long downstream probe-based platform for multiplex target capture

A simple and rapid detection platform was established for multiplex target capture through generating single-strand long downstream probe (ssLDP), which was integrated with the ligase detection reaction (LDR) method for the purpose of multiplicity and high specificity. To increase sensitivity, the ladder-like polymerase chain reaction (PCR) amplicons were generated by using universal primers that complement ligated products. Each of the amplicons contained a stuffer sequence with a defined yet variable length. Thus, the length of the amplicon is an index of the specific suppressor, allowing its identification via electrophoresis. The multiplexed diagnostic platform was optimized using standard plasmids and validated by using potato virus suppressors as a detection model. This technique can detect down to 1.2 × 103 copies for single or two mixed target plasmids. When compared with microarray results, the electrophoresis showed 98.73–100% concordance rates for the seven suppressors in the 79 field samples. This strategy could be applied to detect a large number of targets in field and clinical surveillance.

The effect of weak interactions on the shape of cadmium(II) coordination polymers with pyridine-based hydrazines

Coordination polymers are infinite systems build up from metal ions and organic ligands (linkers) as the main units assembled via coordination bonds and weak interactions (hydrogen bonds, π–π interactions, metal-metal interactions, metal-aromatic interactions). Coordination polymers can extend in one, two or three dimensions. The 1D motif can be represented by linear, zigzag, double, ladder-like chains or helices. 2D and 3D coordination polymers are often called metal-organic frameworks (MOF). These materials have been used in crystal engineering due to their structural diversity and their applications as porous materials, in catalysis, ion exchange and gas storage. Coordination polymers can also have other interesting properties e. g. nonlinear optics, luminescence and magnetism. We have prepared a series of cadmium(II) coordination polymers with isoniazid and niazid and various counterions (chloride, bromide, iodide, thiocyanate). Isonicotinylhydrazine (isoniazid) and nicotinylhydrazine (niazid) are suitable linkers for construction of coordination polymers as they are multidentate ligands - N, O-bidentate and N-bridging. They are capable of satisfying cadmium(II) coordination number (usually 5-7) by acting as N, O-bidentate ligands and they bridge the metal ions at the same time (via pyridine N atom). The aim of our study was to determine the effect of the counterions size, shape and their involvement in weak interactions on dimensionality of cadmium(II) polymers with isoniazid and niazid. In case of chloride and bromide use, we obtained 1D polymers with double chains, linked via chloride/bromide bridging atoms, while in case of iodide use, a 1D polymer with zigzag chain was formed, containing terminal iodide ions only. A 2D polymer was obtained by using thiocyanate ion, as it is an ambidentate ligand with N and S donor atoms, enabling the formation of a network. The polymers were also studied by IR spectroscopy, PXRD and thermal methods (TG/DTA, DSC) and various crystallization techniques were employed to get suitable single crystals for X-ray structure analysis.

Synthesis, solid state structures and urease inhibitory activities of two silver(I) complexes with 1,4-benzodioxane-6-carboxylate

Two new silver(I) complexes, namely [Ag2(BZDO)2(H2O)] (1) and {[Ag(bipy)(BZDO)]·[Ag(bipy)(H2O)](BZDO)·4(H2O)} n (2) (BZDOH = 1,4-benzodioxane-6-carboxylic acid, bipy = 4,4′-bipyridine), were synthesized and structurally characterized. Single-crystal X-ray analysis reveals that complex 1 has a discrete dinuclear silver(I) unit, [Ag2(BZDO)2(H2O)], in which just one water molecule is located in the axial region and two silver atoms are further clamped by a pair of BZDO ligands in a µ 2–η 1:η 1 bridging coordination mode (Ag···Ag = 2.8106(10) A). Complex 2 consists of an [Ag(bipy)(BZDO)] n chain, an [Ag(bipy)(H2O)] + cationic chain, a one-dimensional ladder-like anionic chain formed by uncoordinated BZDO ligands and free water molecules. Both 1 and 2 show potent urease inhibitory activities with the respective IC50 values of 1.60 ± 0.06 and 1.42 ± 0.09 μM.

Structural, spectral and magnetic studies of two Co(II)-N-heterocyclic diphosphonates based on multinuclear units

Two examples of Co(II)-N-heterocyclic coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), namely 0.5(H3NCH2CH2NH3)·[Co6(Cl2)(H3L)2(H2L)(HL)(2,2′-bipy)6] 1 and 2(NH4)·[Co3(HL)2(H2O)2(phen)2]·2(H2O) 2, have been solvothermally obtained by introducing the second ligands 2,2′-bipyridine/1,10-phenanthroline (2,2′-bipy/phen) and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that compound 1 possesses a 0-D structure with hexa-nuclear cluster [Co6(O–P–O)8] built through single/double O–P–O bridges and compound 2 displays a 1-D ladder-like chain structure with magnetic topology building blocks [Co4(O–P–O)4]n. Then H-bonding and π–π stacking interactions further expand the two low-dimensional structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that both the maximum emission peaks of 1–2 are centered at 423nm, mainly deriving from intraligand π*–π transition state of N-heterocyclic ligand 2,2′-bipy/phen, respectively. Magnetism data indicate that 1 exhibits antiferromagnetic behavior within hexa-nuclear Co(II) clusters, while 2 shows weak ferromagnetic interactions in 1-D topology Co(II)-chain, showing promising potential as magnetic materials.

Synthesis, structure and characterization of two new metal-organic coordination polymers based on the ligand 5-iodobenzene-1,3-dicarboxylate.

Two new coordination polymers (CPs) formed from 5-iodobenzene-1,3-dicarboxylic acid (H2iip) in the presence of the flexible 1,4-bis(1H-imidazol-1-yl)butane (bimb) auxiliary ligand, namely poly[[μ2-1,4-bis(1H-imidazol-1-yl)butane-κ(2)N(3):N(3')](μ3-5-iodobenzene-1,3-dicarboxylato-κ(4)O(1),O(1'):O(3):O(3'))cobalt(II)], [Co(C8H3IO4)(C10H14N4)]n or [Co(iip)(bimb)]n, (1), and poly[[[μ2-1,4-bis(1H-imidazol-1-yl)butane-κ(2)N(3):N(3')](μ2-5-iodobenzene-1,3-dicarboxylato-κ(2)O(1):O(3))zinc(II)] trihydrate], {[Zn(C8H3IO4)(C10H14N4)]·3H2O}n or {[Zn(iip)(bimb)]·3H2O}n, (2), were synthesized and characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), solid-state UV-Vis spectroscopy, single-crystal X-ray diffraction analysis and powder X-ray diffraction analysis (PXRD). The iip(2-) ligand in (1) adopts the (κ(1),κ(1)-μ2)(κ(1), κ(1)-μ1)-μ3 coordination mode, linking adjacent secondary building units into a ladder-like chain. These chains are further connected by the flexible bimb ligand in a trans-trans-trans conformation. As a result, a twofold three-dimensional interpenetrating α-Po network is formed. Complex (2) exhibits a two-dimensional (4,4) topological network architecture in which the iip(2-) ligand shows the (κ(1))(κ(1))-μ2 coordination mode. The solid-state UV-Vis spectra of (1) and (2) were investigated, together with the fluorescence properties of (2) in the solid state.

Mono-nuclear and Hexa-nuclear Iron(III) Compounds Based on Phenol-Pyrazole Ligand: Synthesis, Crystal Structure and Magnetic Properties

Reactions of 3-(2-hydroxy-5-methylphenyl)pyrazole (H2Meppz) with different iron salts and bases in solutions lead to compounds [Fe(HMeppz)2Cl] (1) and [Na3Fe6O(OH)7(Meppz)6] (2). These two compounds are then structurally characterized. In mono-nuclear complex 1, iron(III) ion has a square-pyramidal geometry. The mono-nuclear units are further inter-connected by the hydrogen bonds between the N–H of pyrazole ring and the halogen of neighboring molecule to form ladder-like 1D chain. In contrast, substituting the chloride salt with acetate salt, a hexa-nuclear iron(III) cluster 2 is obtained. In 2, the octa-hedral iron ions are interacted with eachother by the hydroxyl bridges, and stabilized by the fully deprotonated Meppz2– ligands. In addition, the magnetic properties of compound 2 had been investigated. Magnetic analysis indicates the presence of antiferromagnetic interactions within the Fe6 cluster.

Crystal structure of a new homochiral one-dimensional zincophosphate containing l-me-thio-nine.

catena-Poly[[(l-me-thio-nine-κO)zinc]-μ3-(hydrogen phosphato)-κ(3) O:O':O''], [Zn{PO3(OH)}(C5H11NO2S)] n , a new one-dimensional homochiral zincophos-phate, was hydro-thermally synthesized using l-me-thio-nine as a structure-directing agent. The compound consists of a network of ZnO4 and (HO)PO3 tetra-hedra that form ladder-like chains of edge-fused Zn2P2O4 rings propagating parallel to [100]. The chains are decorated on each side by zwitterionic l-me-thio-nine ligands, which inter-act with the inorganic framework via Zn-O coordination bonds. The structure displays inter-chain N-H⋯O and O-H⋯S hydrogen bonds.