Two isostructural coordination polymers built by a new bridging chelating ligand: hydrothermal synthesis,crystal structure and photoluminescence

Two new isostructural coordination polymers [Cd(Hadab)(H₂O)] (1) and [Mn(Hadab)(H₂O)] (2) (H₃adab =?3-aminodiacetic benzoic acid) have been synthesized under hydrothermal conditions and characterized by X-ray single crystal analyses, IR spectra and TGA. Compounds 1 and 2 crystallize in the monoclinic space group C2/c and are a 2D network. The 3D pillar-layered networks are constructed by hydrogen bonding interactions between benzoic acid groups. Compound 1 displays intense room temperature photoluminescence in the solid state.     

A new three-connected metal-organic coordination polymer with helical motifs: synthesis,crystal structure and photoluminescence

An interesting metal-organic network with helical motifs, {[Zn₂(mpdc)₂(bpy)(H₂O)₂]?·?2H₂O} (1, mpdc?=?2,6-dimethyl pyrdine-3,5-dicarboxylate), was synthesized under hydrothermal conditions, and characterized. Single-crystal X-ray structural analysis indicates that the title compound crystallizes in a monoclinic lattice, P2(1)/c with a?=?7.811(2), b?=?12.324(3), c?=?15.794(4)A, β?=?98.206(4)°, Z?=?2, V?=?1504.8(7)?ų, D _c?=?1.704?Mg?m^?3, F(000)?=?816, R ₁?=?0.0379, wR ₂?=?0.0807. In the structure of 1 the helical strands composed of [Zn(mpdc)(H₂O)] array in an interlacing fashion, and trap solvated water molecules to assemble a novel supramolecular network. Compound 1 exhibits strong photoluminescence in the solid state at room temperature.     

Synthesis, crystal structure and luminescent properties of a new 3D coordination polymer constructed by Cd(II) with 4,4′-oxybis(benzoate) and 4,4′-bipyridine

A new Cd(II) coordination polymer, [Cd(bpy)(oba)] _n (1) (H₂oba = 4,4′-oxybis(benzoic acid); bpy = 4,4′-bipyridine) has been synthesized under the hydrothermal conditions and structurally characterized by elemental analysis, IR spectrum and single crystal X-ray diffraction. X-ray diffraction analysis reveals that 1 features an interesting 3D framework with wavelike [Cd₂(oba)₂] _n ribbons linked by 4,4′-bpy bridges. The oba ligand adopts chelating and chelating/bridging coordination modes. 1 displays strong fluorescent emission in the solid state at room temperature. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,crystal structure and fluorescence of a two-dimensional coordination polymer with 1-(pyrazin-2-yl)pyridine-2(1H)-one and thiocyanate as mixed bridge ligands

A two-dimensional sheet coordination polymer, [Cd(μ-C₉H₇N₃O)(μ-NCS)₂] _n , (C₉H₇N₃O=1-(pyrazin-2-yl)pyridin-2(1H)-one), has been synthesized with 1-(pyrazin-2-yl)pyridin-2(1H)-one and thiocyanate anion as bridging ligands, and its crystal structure determined by X-ray crystallography. The crystal belongs to monoclinic system with space group P2₁ /c, and its relevant crystal parameters are: a?=?7.5392(16) Å, b?=?18.343(4) Å, c?=?10.155(2) Å, β?=?106.362(3)°, Z?=?4, V?=?1347.4(5) ų, C₁₁H₇CdN₅OS₂, D _Calcd?=?1.980, R?=?0.0516. The crystal structure reveals that both 1-(pyrazin-2-yl)pyridin-2(1H)-one and thiocyanate anion connect adjacent Cd(II) ions resulting in a two-dimensional sheet structure in the bc plane. There are weak π–π stacking interactions between adjacent pyridine rings. The coordination polymer has weaker fluorescent emission in the solid state than 1-(pyrazin-2-yl)pyridin-2(1H)-one compound, attributed to the π–π stacking interaction and the coordination effect.     

Cd(II) and Cu(II) coordination polymers based on a multidentate N-donor ligand: syntheses,crystal structures,optical band gaps,and photoluminescence

Four Cd(II)- and Cu(II)-containing coordination polymers (CPs) based on a multidentate N-donor ligand and varied dicarboxylate anions, [Cd(3,3′-tmbpt)(p-bdc)]·2.5H₂O (1), [Cd(3,3′-tmbpt)(m-bdc)]·2H₂O (2), [Cu(3,3′-tmbpt)(m-bdc)]·H₂O (3), and [Cu(3,3′-tmbpt)(p-bdc)]·2H₂O (4), where 3,3′-tmbpt = 1 ? ((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(3-pyridyl)-1,2,4-triazole, p-H₂bdc = 1,4-benzenedicarboxylic acid, and m-H₂bdc = 1,3-benzenedicarboxylic acid, have been prepared hydrothermally. The structures of the compounds were determined by single-crystal X-ray diffraction analyses and further characterized by infrared spectra and elemental analyses. Compound 1 exhibits a 3-D twofold interpenetrating framework with a 6⁵·8 CdSO₄ topology. Compound 2 is a 2-D layer containing meso-helical chains with a 4⁴·6² sql topology. Compound 3 shows a 1-D → 3-D interdigitated architecture while 4 displays a 2-D → 3-D interdigitated architecture. The structural differences of the compounds indicate that the dicarboxylate anions and the central metal ions play important roles in the resulting structures of CPs. Optical band gaps and solid-state photoluminescent properties have also been studied.     

A twofold interpenetrated 3-D Cu(II) coordination polymer based on 5-(pyridin-4-yl)isophthalic acid: synthesis,crystal structure,and magnetic properties

A new copper(II) coordination polymer, [Cu(PIA)·2H₂O]_n (1) [H₂PIA = 5-(pyridin-4-yl)isophthalic acid], has been synthesized and characterized by elemental analysis, IR spectroscopy, TGA, powder, and single-crystal X-ray diffraction. Structural analysis shows that each PIA^2? in 1 bridges three Cu(II) ions, and likewise each Cu(II) ion connects to three PIA^2? ligands, giving a 3-D framework with utp topology and left-/right-handed helical channels. Interestingly, two such identical frameworks interlock with each other to generate a twofold interpenetrated structure that is stabilized by hydrogen bonding and π–π interactions. In addition, the thermal stability and the magnetic properties of 1 have been investigated.     

Thermal,spectroscopic, X-ray powder diffraction,and structural studies on a new Cd(II) mixed-ligand coordination polymer

A new coordination polymer derived from Cd(II) with both rigid and flexible spacer ligands trans-1,2-bis(4-pyridyl)ethane (bpa) and 4,4′-bipyridine (4, 4′-bipy), {[Cd(μ-bpa)(4, 4′-bipy)₂(H₂O)₂] · (ClO₄)₂} _n has been synthesized and characterized by elemental analysis, IR-, ¹H NMR spectroscopy and studied by thermal analyses as well as X-ray crystallography. The single crystal X-ray analysis shows that the complex is a 1-D polymer as a result of bridging 1,3-di(4-pyridyl)propane (bpa). The 1-D chains are further self-assembled into a 3-D network via hydrogen bonding and π–π stacking. In this structure the perchlorates fill the voids. Thermal studies of this polymer show step to step separating of ligands and counter ion at different temperatures.     

Synthesis,crystal structure,and blue photoluminescence of a 3D coordination polymer based on a Ag10 cluster with the versatile 2-mercapto-5-benzimidazolesulfonic acid ligand

The solvothermal reaction of 2-mercapto-5-benzimidazolesulfonic acid (H₃MBZD), which has imidazole, –SH, and –SO₃H groups, with Ag₂SO₄ led to the 3D coordination polymer {Ag₅[(HMBZD)₂(H₂MBZD)(H₂O)]} _n (1). X-ray single-crystal analysis showed that five independent Ag atoms are connected by the bridging mercapto group to generate asymmetric pentanuclear clusters, which are joined together to form a large Ag₁₀ ringed subunit. The Ag₁₀ subunits are linked together by the –SO₃H groups to give the complex 3D framework. Strong blue photoluminescence of 1 can be assigned to the intraligand fluorescent emission.     

A 3D porous zinc MOF constructed from a flexible tripodal ligand: Synthesis, structure, and photoluminescence property

A new metal-organic framework, [Zn₅(trencba)₂(OH)₂Cl₂·4H₂O] (1) [H₃trencba=N,N,N′,N′,N′′,N′′-tris[(4-carboxylate-2-yl)methyl]-tris(2-aminoethyl)amine], constructed from a flexible tripodal ligand based on C₃ symmetric tris(2-aminoethyl)amine, has been synthesized hydrothermally and characterized by elemental analysis, IR, TG, XRD and single-crystal X-ray diffraction analysis. Compound 1 contains an unprecedented linear penta-nuclear zinc cluster fragment. Each ligand links four penta-nuclear fragments, and every fragment links eight ligands to generate a three-dimensional non-interpenetrated porous framework. The uncoordinated water molecules were observed trapped in the void pores. Compound 1 represents the first example of (6,8)-connected 3D bi-nodal framework based on a single kind of organic ligand. The photoluminescence measurements showed that complex 1 exhibits relatively stronger blue emissions at room temperature than that of the ligand.     

A novel three‐dimensional copper(I) cyanide coordination polymer constructed from various bridging ligands: synthesis,crystal structure and characterization

The cyanide ligand can act as a strong σ‐donor and an effective π‐electron acceptor that exhibits versatile bridging abilities, such as terminal, μ₂‐C:N, μ₃‐C:C:N and μ₄‐C:C:N:N modes. These ligands play a key role in the formation of various copper(I) cyanide systems, including one‐dimensional (1D) chains, two‐dimensional (2D) layers and three‐dimensional (3D) frameworks. According to the literature, numerous coordination polymers based on terminal, μ₂‐C:N and μ₃‐C,C,N bridging modes have been documented so far. However, systems based on the μ₄‐C:C:N:N bridging mode are relatively rare. In this work, a novel cyanide‐bridged 3D Cu^I coordination framework, namely poly[(μ₂‐2,2′‐biimidazole‐κ²N³:N^3′)(μ₄‐cyanido‐κ⁴C:C:N:N)(μ₂‐cyanido‐κ²C:N)dicopper(I)], [Cu₂(CN)₂(C₆H₆N₄)]_n, (I), was synthesized hydrothermally by reaction of environmentally friendly K₃[Fe(CN)₆], CuCl₂·2H₂O and 2,2′‐biimidazole (H₂biim). It should be noted that cyanide ligands may act as reducing agents to reduce Cu^II to Cu^I under hydrothermal conditions. Compound (I) contains diverse types of bridging ligands, such as μ₄‐C:C:N:N‐cyanide, μ₂‐C:N‐cyanide and μ₂‐biimidazole. Interestingly, the [Cu₂] dimers are bridged by rare μ₄‐C:C:N:N‐mode cyanide ligands giving rise to the first example of a 1D dimeric {[Cu₂(μ₄‐C:C:N:N)]ⁿ⁺}_n infinite chain. Furthermore, adjacent dimer‐based chains are linked by μ₂‐C:N bridging cyanide ligands, generating a neutral 2D wave‐like (4,4) layer structure. Finally, the 2D layers are joined together via bidentate bridging H₂biim to create a 3D cuprous cyanide network. This arrangement leads to a systematic variation in dimensionality from 1D chain→2D sheet→3D framework by different types of bridging ligands. Compound (I) was further characterized by thermal analysis, solid‐state UV–Vis diffuse‐reflectance and photoluminescence studies. The solid‐state UV–Vis diffuse‐reflectance spectra show that compound (I) is a wide‐gap semiconductor with band gaps of 3.18 eV. The photoluminescence study shows a strong blue–green photoluminescence at room temperature, which may be associated with metal‐to‐ligand charge transfer.     

A six-coordinate picrate cadmium(II) complex with a new V-shaped ligand 1,3-bis(1-ethylbenzimidazol-2-yl)-2-thiapropane: synthesis,crystal structure,and DNA-binding properties

A V-shaped ligand 1,3-bis(1-ethylbenzimidazol-2-yl)-2-thiapropane (L) and its picrate cadmium(II) complex have been synthesized and characterized systematically. In [Cd(L)₂](pic)_2, the Cd(II) is six-coordinate with N₄S₂ donors of two ligands, forming a slightly distorted octahedron. DNA binding properties were investigated by electronic absorption spectroscopy, fluorescence spectroscopy, and viscosity measurements. The compounds bind to DNA via intercalation and the order of binding affinity is ligand>complex.     

A new 2-D cobalt coordination polymer with the flexible 2-(1H-imidazole-1-yl)acetate: synthesis,structure, and characterization

A new cobalt coordination polymer with linking unit 2-(1H-imidazole-1-yl)acetate (ima), [Co(ima)₂] _n (1), has been synthesized and structurally characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. The X-ray analysis indicates that a neutral 2-D coordination polymer with (3,6) topology was obtained, which shows a 3-D supramolecular network through C–H···O weak interactions. Complex 1 displays mild antimicrobial activity against Achromobacter xylosoxidans ATCC 2706, Bacillus subtilis ATCC 6633, and Candida albicans ATCC 90028, respectively. The magnetic and thermal gravimetric properties for 1 have been investigated and discussed.     

Synthesis and crystal structure of a novel Zn(II) 2-D coordination polymer containing 1,3-bis(4-pyridyl)propane ligand and Croconate Violet dianion

From the reaction between Zn(NO₃)₂ · 6H₂O and tetrabutylammonium croconate violet ((NBu₄)₂CV) in the presence of the flexible ligand 1,3-bis(4-pyridyl)propane (BPP) a novel neutral 2-D coordination polymer {[Zn(μ-BPP)(BPP)(CV)(H₂O)] · H₂O}_n (1) was obtained. Compound 1 was characterized by means of elemental analysis, thermogravimetric analysis and vibrational spectroscopy. The crystal structure of 1 reveals that each Zn(II) is coordinated by three nitrogen atoms from two different BPP ligands, two oxygen atoms from one Croconate Violet dianion and one aqua ligand, within a distorted octahedral geometry in a facial arrangement (ZnN₃O₃). One of the BPP ligands adopts a TG (trans–gauche) conformation bridging two zinc centers giving rise to a 1-D polymeric chain along the crystallographic a axis, and the other is coordinated to metal site in a monodentate fashion adopting a TT (trans–trans) conformation. Adjacent 1-D chains are extended into a 2-D coordination network of (4, 4) topology through cooperative hydrogen bonding involving N31, OW2 and OW1 atoms, in direction of the c axis. Two complementary 2-D sheets fit each other exhibiting an interdigitation phenomenon, giving rise to a bilayer supramolecular structure.     

3D zinc(II) coordination polymers built up by triazole and benzene-polycarboxylate anions: Synthesis,crystal structure,thermal and photoluminescence characterization

Two coordination polymers of the formula [Zn₅(tmaH)₄(trz)₂(H₂O)₄] (1) and [Zn₃(bta)(trz)₂(H₂O)₄]·2H₂O (2) [tmaH₃ = benzene-1,3,5-tricarboxylic acid/trimesic acid, trzH = 1,2,4-triazole, btaH₄ = benzene-1,2,4,5-tetracarboxylic acid] have been synthesized and structurally characterized by X-ray single crystal diffraction analysis. Both complexes are 3D coordination polymers containing [Zn₄(trz)₂] units connected by benzene-carboxylate anions. In particular, an undulated layer containing 6- and 18-membered rings is outlined in the network of 1. Hydrogen bonds, involving the coordinated and lattice water molecules with carboxylate oxygen atoms, contribute to the stabilization of the networks. Their thermal stability was investigated by thermogravimetric analysis. The fluorescence spectrum of 1 features two peaks at 419 and 323 nm, originating from a π–π∗ intraligand transition and LMCT, respectively. For 2 a broad band at 410 nm is assigned solely as a π–π∗ intraligand transition.     

Nanoparticles of a new mercury(II) coordination polymer: synthesis,characterization, thermal and structural studies

Nanoparticles of a new Hg(II) one-dimensional coordination polymer, {[Hg(4-bpdb)I₂] _n , 4-bpdb?=?1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene} were synthesized by reaction of HgI₂ and 4-bpdb by a sonochemical method. The new nanoparticles were characterized by scanning electron microscopy, X-ray powder diffraction (XRD) and FT-IR spectroscopy; [Hg(4-bpdb)I₂] _n was structurally characterized by single crystal X-ray diffraction. This compound consists of one-dimensional polymeric units of [Hg(4-bpdb)I₂]. The thermal stability of [Hg(4-bpdb)I₂] _n was studied by thermal gravimetric (TG) and differential thermal analyses (DTA).     

A Pb2+-based coordination polymer with 5-(1H-tetrazol-5-yl)isophthalic acid ligand: structure and photoluminescence

A coordination polymer, [Pb₂(OH)(tzia)]·2H₂O (1), has been prepared by solvothermal reaction of 5-(1H-tetrazol-5-yl)isophthalic acid (H₃tzia) and Pb(NO₃)₂. The polymer 1 is based on an unprecedented centrosymmetric tetranuclear [Pb₄(OH)₂(COO)₄(ttaz)₂] cluster linked by a multidentate tzia ligand, affording a 2-D 3,6-connected kgd layer. The adjacent layers are further jointed by Pb?O interactions to form a 3-D supramolecular framework with a rare (3,8)-connected tfz-d; UO₃ topology. Photoluminescent properties of H₃tzia, 1, and 1-desolvated have been further investigated, and it was interesting to find that 1-desolvated due to the removal of lattice water molecules reveals stronger photoluminescence than 1.     

A new lanthanum coordination polymer built from a semi‐rigid tripodal carboxylic acid ligand: synthesis,crystal structure and properties

By employing the semi‐rigid multidentate carboxylic acid ligand 4,4′,4′′‐{[(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris(methylene)]tris(oxy)}tribenzoic acid (denoted H₃L), a new lanthanum coordination polymer, namely poly[[bis(dimethylformamide)(μ₆‐4,4′,4′′‐{[(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris(methylene)]tris(oxy)}tribenzoato)lanthanum(III)] dimethylformamide tetrasolvate 0.25‐hydrate], {[La(C₃₃H₂₇O₉)(C₃H₇NO)₂]·4C₃H₇NO·0.25H₂O}_n or {[La(L)(DMF)₂]·4(DMF)·0.25(H₂O)}_n (DMF is dimethylformamide) ( 1 ), was prepared and characterized by single‐crystal X‐ray diffraction, elemental analysis, thermogravimetric analysis, IR spectroscopy and photoluminescence studies. The asymmetric unit contains one La^III cation, one anionic L^3? ligand, two coordinated DMF molecules, four free DMF molecules and one‐quarter of a free water molecule. Compound 1 possesses (3,6)‐connected two‐dimensional kgd topology sheets consisting of secondary building units of La₂ clusters and L^3? ligands, which further stack into three‐dimensional supramolecular networks through π–π interactions. Compound 1 exhibits a photoluminescence emission at room temperature, with a peak at 410 nm, owing to a ligand‐centred excited state.     

Dimeric and polymeric silver(I) saccharinato complexes of two bis(pyridine) ligands: Synthesis,structural, spectroscopic,fluorescent and thermal properties

The reaction of silver(I) with 1,2-bis[1-(pyridin-2-yl)ethylidene]hydrazine (bpeh) and N,N-bis(pyridin-2-ylmethyl)amine (bpma) in the presence of Na(sac) (sac = saccharinate) yielded [Ag₂(sac)₂(bpeh)] (1) and [Ag(sac)(bpma)]_n (2) with conformational chirality. Both complexes have been characterized by elemental analysis, IR, thermal analysis and X-ray single crystal diffraction. Complex 1 displays a binuclear composition, in which each silver(I) ion is bound to one monodentate sac ligand and one of the bidentate pyridylimino groups of the bpeh ligand in a distorted trigonal coordination geometry. Complex 2 is a one-dimensional helical polymer, in which silver(I) centers are bridged by tridentate bpma ligands, and each silver(I) ion is coordinated in a distorted tetrahedral geometry by one monodentate sac ligand, a bidentate pyridylamine group of one bpma ligand, and a py group of another bpma ligand. Weak intermolecular C–H?O hydrogen bonds and C–H?π interactions lead to assembly of 1 and 2 into three-dimensional supramolecular frameworks. Spectral and thermal analysis data for 1 and 2 are in agreement with the crystal structures. In addition, both complexes in the solid state display intraligand π–π∗ fluorescence.     

Synthesis,crystal structure,and third-order non-linear optical properties of a new Cd(II) polymer constructed from pyrazine-2-carboxylic acid

A new cadmium(II) pyrazine-2-carboxylate coordination polymer, {[Cd(L)(H₂O)₂(SO₄)_0.5]₂·H₂O}_n (1) (HL = pyrazine-2-carboxylic acid), has been synthesized by low-temperature solid-state reaction. Single-crystal X-ray analyses reveal that 1 possesses a 3-D framework structure. The polymer 1 was characterized by elemental analyses, thermogravimetric analyses, X-ray powder diffraction analyses, IR spectra, and UV–visible spectra. The third-order non-linear optical properties were also investigated and they exhibit nice non-linear absorption and self-defocusing performance with modulus of the hyperpolarizability (γ) 1.30 × 10^?30 esu for 1 in a 2.01 × 10^?4 M?dm^?3 DMF solution.