Solvent-induced two heterometallic coordination polymers based on a flexible ferrocenyl ligand

The bidentate ferrocenyl sandwich molecule N,N′-bis-3-pyridylmethyl-1,1′-ferrocenedicarboxamide (3-BPMFA) has been employed as an organometallic coordination ligand in reaction with CdBr₂ to construct heterobimetallic architectures. By assembling the flexible arm-like molecule with CdBr₂, two novel bimetallic 1D chain structures are constructed in different solvent systems: the solvated [Cd(μ-3-BPMFA)₂Br₂]_n·nMeOH (1) from methanol and the unsolvated [Cd(3-BPMFA)(μ-Br)₂]_n (2) from DMF–Et₂O. Different roles of bromine ions have been observed in these two complexes. In 1, bromine ions only act as terminal coordinated ligand, while they play bridging roles in 2. Electrochemistry properties of the ligand and complexes were discussed preliminarily.     

Temperature-controlled structural diversity of two Cd(II) coordination polymers based on a flexible tripodal multicarboxylate ligand

Two new 3-D Cd(II) coordination polymers (CPs) with 3,5-bi(4-carboxyphenoxy)-benzoic acid (H₃L), namely [Cd₃(L)₂(H₂O)₄]·4H₂O (1) and [Cd₃(L)₂(H₂O)₃]·2H₂O (2), were successfully synthesized under hydrothermal condition at 140 °C and 180 °C, respectively. Complex 1 is constructed from 1-D (–Cd–O–)_∞ rod-shaped SBUs (secondary building units) and ‘Y’-shaped L ligands. In complex 2, the 3-D network is mediated by 2-D [Cd(COO)₂]_n layered motifs and ‘T’ and ‘Y’-shaped L ligands. The results show that the reaction temperature plays a key role on the final structures of the complexes. The luminescent properties of the complexes have also been investigated.     

Tuning structural topologies of two coordination polymers via alter N-donor auxiliary ligand

Based on the N-donor auxiliary ligand effect, two new Ni(II) coordination polymers [Ni₂(HL)₂(bpe)₂] (1) and [Ni(HL)(bipy)(H₂O)₂] (2) [H₃L = 2-(4′-carboxyphenyl)terephthalic acid; bpe = 1,2-bis(4-pyridyl)ethane; bipy = 4,4′-bipyridine] have been successfully synthesized and characterized by single-crystal X-ray diffraction study, elemental analysis, IR spectra, TGA and powder X-ray diffraction (PXRD). This work presents a comparative study on the tuning of structural topologies by using two N-donor ligands with different lengths as auxiliary ligands. The structural determination reveals that complex 1, incorporating bpe ligands, features a three-dimensional (3D) 4-connected 4-fold dia interpenetrating architecture with the point symbol of 6⁶, while 2, containing bipy ligands, exhibits a two-dimensional (2D) sql layer structure with a 4-connected (4⁴·6²) topology. Moreover, the magnetic properties for 1 and 2 were also measured and compared on account of their different structures.     

Fluorescent selectivity for small molecules of two coordination polymers based on a tetracarboxylate ligand

Two coordination polymers [Cd(tptc)_0.5(4,4′–bibp)]_n (1) and {[Zn₃(Htptc)₂(phen)₂]·1.5H₂O}_n (2) (H₄tptc = terphenyl-3,3″,5,5″-tetracarboxylic acid, 4,4′-bibp = 4,4′-bis(imidazolyl)biphenyl, and phen = 1,10-phenanthroline) were synthesized under solvothermal conditions. Complex 1 displays a 3D structure with a Schläfli symbol of {4⁴.6²}{4⁸.6²⁰}. Complex 2 possesses a 2D layer network, incorporating [Zn₃(COO)₆] second building units (SBUs), which is packed into a 3D supramolecular architecture by π ⋯ π interactions. Both of them exhibit strong luminescence characteristics. It is worth to note that complexes 1 and 2 show potential application to detect small organic molecules.     

Construction of two novel coordination polymers from a V-shaped bisimidazole ligand: Synthesis,characterization and properties

Two novel coordination polymers, [Cd₂(cdc)₂(bmis)₂] (1) and [Zn₆(cdc)₄(OH)₄(bmis)₄]·2H₂O·4DMF (2) (bmis = bis(4-(2′-methylimidazol-ylphenyl)sulfone, H₂cdc = 1,4-cyclohexanedicarboxylic acid), have been synthesized and structurally characterized. Compound 1 features an interesting usf net presenting the alternate arrangement of the single- and triple-stranded helices. Compound 2 exhibits an unusual two-fold interpenetrating polyrotaxane motif composed of two interlocked sets of identical pcu nets. In addition, their photoluminescent properties have also been evaluated.     

Syntheses and physical properties of three-dimensional coordination polymers with the flexible tripodal ligand 1,3,5-tris(1,2,4-triazol-1-ylmethyl)benzene

Two 3D organic–inorganic hybrid coordination polymers, [M₂(ttmb)₂(SO₄)₂(H₂O)₂] · 7H₂O (M = Cd, 1; M = Mn, 2; ttmb = 1,3,5-tris(1,2,4-triazol-1-ylmethyl)benzene), have been synthesized and structurally characterized. They are isostructural and possess a 3D architecture fused from 2D (4,4) M(ttmb) networks and MSO₄ chains by sharing “hinge” metal atoms. The thermal properties of 1 and 2, luminescent property of 1 as well as magnetic property of 2 have been investigated.     

Synthesis,luminescence, and structural characterization of Zn and Cd coordination polymers of flexible bis(imidazolyl) derivatives

Coordination polymers [Zn(imc)(L¹)] · H₂O, (1, imc = iminodiacetate, L¹ = bis(N-imidazolyl)methane) [Zn(hba)₂(L²)]₂ · EtOH · 3H₂O, (2, hba = p-hydroxybenzoate, L² = bis(N-benzimidazolyl)methane), [Cd(mal)(H₂O)(L³)](3, L³ = 1,4-bis(N-imidazolyl)butane, mal = maleate) have been prepared and structurally characterized. Complex 1 consists of hexa-coordinated central Zn ions and exhibits 2D network structure. The Zn atoms in 2 have tetrahedral coordination geometry, and are linked by bis(imidazolyl) ligands into 1D chain structure. The cadmium ions in 3 are hepta-coordinated with pentagonal bipyramidal geometry. Complex 3 displays 2D grid structure. The TGA showed that the coordination polymers are stable up to 200 °C. All the three complexes are emissive at room temperature in their solid state.     

Assembly of two Cu-based coordination polymers from 2-(pyridine-3-yl)-1H-4,5-imidazoledicarboxylate ligand

Two novel Cu-based coordination polymers [Cu₅(HPyImDC)₄]·(NH₄)₃ (1) and [Cu₃(H₂O)₂(HPyImDC)₂(C₃N₂H₁₀)] (2) containing the 2-(pyridine-3-yl)-1H-4,5-imidazoledicarboxylate (H₃PyImDC) ligand have been solvothermally synthesized. Single crystal X-ray diffraction analysis reveals that compound 1 exhibits a three dimensional framework with 1D rhombic channels, which can be simplified into a novel (3, 4)-connected network with Schläfli symbol of (6².14⁴)(6².8)₄. Compound 2 is one dimensional chain which packed with each other via π–π and hydrogen-bonding interactions to construct a three dimensional supramolecular structure. As the first example related to Cu (I) and Cu (I, II) coordination polymers based on H₃PyImDC ligands, compounds 1 and 2 are further studied by elemental analyses, IR spectroscopy and thermogravimetric analyses.     

Syntheses,structures and photoluminescence properties of two 2D Cd(II) coordination polymers based on a semirigid tridentate N-donor ligand

The assembly of a semirigid tridentate N-donor ligand with Cd(II) ions afforded two novel coordination polymers, [Cd(tipa)(H₂O)₂·2NO₃·2DMF·H₂O]_n (1), [Cd₂(tipa)₂Cl₄·2DMF·6H₂O]_n (2), where tipa = tris(4-(1H-imidazol-1-yl)phenyl) amine. Structural analyses indicate that the two compounds feature 2D layered networks. A 3-connected uninodal net with point symbol of (8²·10) is constructed in compound 1 by the connection of tipa and metal ions, in which the terminally coordinated water molecules prevent further extension of the layer. Compound 2 features [Cd₂Cl₄] motifs, which are bridged by tridentate tipa ligands into a 2D (3,6)-connected layer. The results show that tipa with different dihedral angles between benzene ring and terminal imidazole groups can act as versatile building blocks for the generation of various networks. Moreover, the photoluminescence properties of 1 and 2 in the solid state at room temperature have been investigated.     

Hydrothermal syntheses and crystal structures of PbII coordination polymers based on a N,O-donor ligand

In this article, four new lead(II) coordination polymers based on a N,O-donor ligand 2′-(1 H-1,3,7,8-tetraaza-cyclopenta[l]phenanthren-2-yl)biphenyl-2-carboxylic acid (HL) have been hydrothermally synthesized, namely, [PbL₂]·2H₂O (1), [PbL₂]·2H₂O·CH₃CH₂OH (2), [Pb₅L₂(m-BDC)₄]·3H₂O (3) and [Pb₂L₂(p-BDC)] (4), where m-BDC = 1,3-benzenedicarboxylate and p-BDC = 1,4-benzenedicarboxylate. Compound 1 shows a 2D bilayer structure, which is further extended into a 3D supramolecular structure through π–π stacking interactions. Compound 2 shows a 3D supramolecular structure based on a zero-dimensional molecule by π–π stacking interactions of neighboring molecules. Compound 3 shows a 2D layer structure. Compound 4 displays a 1D chain-like structure, which is then stacked by π–π interactions to result in a 2D supramolecular structure. Solid-state luminescent spectra of four lead(II) complexes indicate intense fluorescent emissions.     

Syntheses,crystal structures,and magnetic studies of two cobalt(II) coordination polymers based on concurrent ligand extension

An ether bridged tetracarboxylic acid ligand, 5-(3′,4′-Dicarboxylphenoxy)-isophthalic acid (H₄L) was used to construct two Co(II) coordination polymers in presence of different nitrogen donor ligands such as 4,4′-bipyridine (4,4′-bpy) and 4,4′-bis(pyrid-4-yl)biphenyl (bpbp). The products formed under hydrothermal conditions are formulated as [Co₂L(4,4′-bpy)₂(H₂O)₃]_n (1) and {[Co(bpbp)₂(H₂L)]·H₂O}_n (2). The compounds were characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, and powder X-ray diffraction (PXRD) measurement. Compound 1 shows an intriguing (3,4,5)-connected 3D framework with a point symbol of (4² · 6² · 8²)(4² · 6⁵ · 8³)(6² · 8). Compound 2 is an unusual 3D supramolecular framework generated by the one-dimensional [Co(bpbp)(H₂L)]_n polymer chain. The magnetic properties of compounds 1 and 2 were examined, indicating antiferromagnetic interactions between the cobalt(II) ions in the temperature range of 2–300 K.     

Blends of a thermotropic liquid crystalline polymer and some flexible chain polymers and the determination of the polymer-polymer interaction parameter of the two polymers

Summary Blends of a thermotropic liquid crystalline polymer (LCP) with poly(ether imide) (PEI), poly(ether ether ketone) (PEEK), polysulfone (PSF) and polyarylsulfone (PAS) prepared by screw extrusion have been investigated by differential scanning calorimeter and dynamic mechanical thermal analysis. From the measured glass transition temperature (T_g) and specific heat increment (ΔC_p) at the T_g, it appears that the LCP dissolves more in the PEI- and PEEK-rich phases than does the PEI and PEEK in the LCP-rich phase. From the DSC study of PSF-LCP and PAS-LCP blends, the T_g(PSF) and T_g(PAS) of each blends are almost constant with blend composition. Therefore, it is concluded that PSF and PAS are immiscible with LCP. The polymer-polymer interaction parameter (χ₁₂) and the degree of disorder (y/x₁) of LCP have been investigated using the Flory lattice theory in which the anisotropy of LCP is considered. The χ₁₂ values have been calculated from the T_g data and found to be 0.181 ± 0.004 at 593 K for the PEI-LCP blends and 0.069 ± 0.006 at 623 K for the PEEK-LCP blends. Using the previously presented method, the χ₁₂ and y/x₁ in partially miscible systems have been determined. Received: 6 April 1998/Revised version: 8 June 1998/Accepted: 17 June 1998     

Influence of hydrothermal synthesis temperature on the structures of two 3D coordination polymers

Two 3D coordination polymers [Zn(μ₄-dmbdc)]_n, 1 and [Zn₅(μ₃-OH)₄(μ₅-dmbdc)₂(μ₄-dmbdc)]_n, 2 (H₂dmbdc = 2,5-dimethylbenzenedicarboxylic acid) have been prepared by hydrothermal syntheses with temperature as the only variable. The structure feature is the presence of monoatomic coordination bridges, i.e. μ₃-OH and μ₂-O (from μ₃-COO⁻ of μ₅-dmbdc) in 2 synthesized at higher temperature. The coordination number of zinc ion and the bridging number of the carboxyl group increase with the increasing synthesis temperature, resulting in the formation of the more stable and condensed phase.     

Construction of two photoluminescent sulfur-containing cadmium(II) coordination polymers with 4-connected topology based on a methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate ligand

Two new Sulfur-containing Cadmium(II) coordination polymers {[Cd(HL)₂](2H₂O)}_n (1) and {[Cd(L)(bmie)(H₂O)](H₂O)}_n (2) (H₂L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate, and bmie = 1,2-bis(imidazol-1′-yl)ethane) have been successfully constructed and structurally characterized by the single-crystal X-ray diffraction and other characterization techniques, such as elemental analysis, IR spectroscopy and thermogravimetric analysis. Structural analyses reveal that complex 1 exhibits a hydrogen bonded-extended 3D supramolecular structure based upon 4-connected sql layers assembled from single Cd(II) centers as nodes. Complex 2 features a 3D network which can be rationalized as a rare 4-connected cdl topology. It is shown that the H₂L ligand is a suitable building block in constructing coordination polymers with structural diversities. Moreover, solid photoluminescent properties have been investigated.     

Hydrothermal synthesis and crystal structure of a novel Keggin polyoxoanion-templated multichain coordination polymer with a flexible bis(imidazole) ligand

By introducing the flexible 1,1′-(1,4-butanediyl)bis(imidazole) (bbi) ligand into the Keggin system, a novel multi-chain compound, (bbi)_1.5[Cu(bbi)]_4.5[PW₁₂O₄₀]_1.5 (1) was synthesized under the hydrothermal conditions. It was characterized by elemental and TG analysis, IR and XPS spectra, cyclic voltammetry, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Compound 1 features in two sorts of polyoxometalates (POMs) chains, the poly-chain of [Cu(bbi)]_4.5[PW₁₂O₄₀] and the single-chain of (bbi)[PW₁₂O₄₀]_0.5, induced by the POM clusters.     

Anion-directed self-assembly of metallosupramolecular coordination polymers of the radialene ligand hexa(2-pyridyl)[3]radialene

Hexa(2-pyridyl)[3]radialene was prepared by reaction of di-2-pyridylmethane with tetrachlorocyclopropene. Reaction of this ligand with silver nitrate and silver hexafluorophosphate gave two different one-dimensional coordination polymers each with a 2:1 metal–ligand composition. X-ray crystal structures revealed that the structure and topology of the coordination polymer is strongly influenced by the anion. In the reaction with silver nitrate the ligand self-assembled to give a helical one-dimensional coordination polymer, but when silver hexafluorophosphate was used, a coordination polymer, composed of Ag₃L₂ prismate cages linked by linear-bridging silver atoms, was obtained.     

The effects of molecular configuration on the photochromism and decolorization of two bipyridinium-based coordination polymers

Two layer-like coordination polymers, {[Cd(Bpyen)_0.5(m-BDC)(H₂O)Br]·4H₂O}(1) and {[Cd(Bpyen)_0.5(o-BDC)Br]·H₂O}(2), have been solvothermally synthesized and structurally characterized. The two compounds own common rapid photochromic response but different decolorization behaviors. The photoproduct of compound 2 is more stable in air. The relationship between structure and photoresponsive behavior has been studied in detail.     

Design and construction of two new polymers featuring macrocyclic subunits based on a rigid clamp-like ligand

Reaction of a rigid conjugated clamp-like ligand N,N′-bis(pyridin-3-yl)-2,6-pyridinedicarboxamide (bppdca) with ZnSO₄·7H₂O or CoSO₄·7H₂O resulted in the formation of two new polymers, namely, {[Zn₂(bppdca)(SO₄)₂(DMF)₂]·(DMF)}_n (1) and {[Co(bppdca)(SO₄)(CH₃OH)(DMF)]·H₂O}_n (2). Both 1 and 2 feature one-dimensional double-chain structures with macrocyclic subunits, and the chains further self-assemble into a higher-dimensional framework via the hydrogen-bonding and π–π stacking interactions. Fluorescence studies show that the free ligand displays a strong fluorescence emission in solid state at room temperature, but in 1 and 2, the complexation of the ligand with metal ions and weak intermolecular interactions make the fluorescence emission partial quenching.     

Hydrothermal syntheses of two novel coordination polymers based on tetranuclear metal cluster constructed by 1,3,5-Tris(2H-tetrazol-5-yl)benzene ligand

Two new coordination polymers, namely [Zn₃(BTT)(μ₃-OH)₃] (1), and [Mn₃(BTT)(μ₃-OH)₃] (2), where H₃BTT = 1,3,5-Tris(2H-tetrazol-5-yl)benzene, have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction. The structure of compound 1 can be described as tetranuclear zinc cluster linked with zinc (Zn2^II) atoms to form a 2D layer, and the adjacent parallel layers bridged by the rigid H₃BTT ligand to show 3D network. Taking Mn ions in replace of Zn ions, a new compound 2 is successfully obtained which is isostructural with 1. In addition, photoluminescent property for 1, magnetic properties for 2 and thermogravimetric analyses for 1 and 2 are investigated in detail.