Polymeric Zigzag Research Articles

Polymerization of Nitrogen in Nitrogen-Fluorine Compounds under Pressure.

A wide range of polynitrogen species have attracted much attention because of their potential applications as high-energy-density materials. Until now, predicted polynitrogen was found to be negatively charged, with charge transfer from introduced atoms to nitrogen in nitrogen-bearing compounds. Using an evolutionary algorithm combined with first-principles calculations, stoichiometries and structures in nitrogen-fluorine compounds at pressures ranging from 0 to 200 GPa are investigated. In addition to two fluorine-rich compounds NF3 and NF5, two other compounds, NF and N6F, emerge with increasing pressure. N6F, as a nitrogen-rich compound, will become stable at pressures greater than 180 GPa with a positively charged nitrogen network. Above 120 GPa, the NF compound with polymeric zigzag nitrogen chains is discovered, and it is quenchable to the ambient conditions, acquiring the highest energy density of 5.38 kJ/g among reported binary covalent nitrogen compounds. These newly predicted N-F compounds are useful in understanding the chemistry of polynitrogen.

Manipulating the Conformation of 3,2′:6′,3″-Terpyridine in [Cu2(μ-OAc)4(3,2′:6′,3″-tpy)]n 1D-Polymers

We report the preparation and characterization of 4′-([1,1′-biphenyl]-4-yl)-3,2′:6′,3″-terpyridine (1), 4′-(4′-fluoro-[1,1′-biphenyl]-4-yl)-3,2′:6′,3″-terpyridine (2), 4′-(4′-chloro-[1,1′-biphenyl]-4-yl)-3,2′:6′,3″-terpyridine (3), 4′-(4′-bromo-[1,1′-biphenyl]-4-yl)-3,2′:6′,3″-terpyridine (4), and 4′-(4′-methyl-[1,1′-biphenyl]-4-yl)-3,2′:6′,3″-terpyridine (5), and their reactions with copper(II) acetate. Single-crystal structures of the [Cu2(μ-OAc)4L]n 1D-coordination polymers with L = 1–5 have been determined, and powder X-ray diffraction confirms that the single crystal structures are representative of the bulk samples. [Cu2(μ-OAc)4(1)]n and [Cu2(μ-OAc)4(2)]n are isostructural, and zigzag polymer chains are present which engage in π-stacking interactions between [1,1′-biphenyl]pyridine units. 1D-chains nest into one another to give 2D-sheets; replacing the peripheral H in 1 by an F substituent in 2 has no effect on the solid-state structure, indicating that bifurcated contacts (H...H for 1 or H...F for 2) are only secondary packing interactions. Upon going from [Cu2(μ-OAc)4(1)]n and [Cu2(μ-OAc)4(2)]n to [Cu2(μ-OAc)4(3)]n, [Cu2(μ-OAc)4(4)]n, and [Cu2(μ-OAc)4(5)]n·nMeOH, the increased steric demands of the Cl, Br, or Me substituent induces a switch in the conformation of the 3,2′:6′,3″-tpy metal-binding domain, and a concomitant change in dominant packing interactions to py–py and py–biphenyl face-to-face π-stacking. The study underlines how the 3,2′:6′,3″-tpy domain can adapt to different steric demands of substituents through its conformational flexibility.

Luminescent gold-thallium derivatives with a pyridine-containing 12-membered aza-thioether macrocycle.

The coordination modes of the ligand 2,5,8-trithia[9](2,6)pyridinophane (L) to thallium(i), gold(iii) and gold(i) have been studied. Thallium(i) is coordinated by the macrocyclic ligand in [Tl(L)](PF6) (1) through all the sulfur and nitrogen atoms, in a distorted square-pyramidal geometry with the thallium(i) ion in the apical position and with the presence of an inert lone pair. Gold(iii) is bonded by the ligand only through the nitrogen of the pyridine group in [AuCl3(L)] (2), whereas two AuI-C6F5 fragments coordinate the sulfur atoms next to the pyridine moiety of the ligand in [{Au(C6F5)}2(μ-L)] (3), which form a linear polymer through intermolecular aurophilic contacts. The heterometallic TlI/AuI complex {[Au(C6F5)2Tl]2(L)}n (4) features a polymeric structural nature with a metallic pseudo-rhombic Au2Tl2 core, which repeats itself forming a zig-zag polymer. In each Au2Tl2 unit only one thallium atom is bonded by the NS3 donor set of the macrocyclic ligand and also forms two unsupported Au-Tl bonds with two [Au(C6F5)2]- units in an overall pseudo-octahedral geometry. The other thallium atom similarly bridges the same [Au(C6F5)2]- units and links a neighbouring Au2Tl2 moiety, thus exhibiting a distorted trigonal planar geometry being bonded only to three gold atoms with unsupported Au-Tl interactions. This complex displays an interesting thermochromic behaviour showing emissions mainly resulting from MM'CT transitions at room temperature. At 77 K a dual emission appears, probably arising from the two different thallium environments. DFT calculations have been carried out in the attempt to investigate the origin of the emissions of complex 4.

Chemoselective On-surface Homocoupling of Terminal Alkynes Catalyzed by Exogenous Cupric Ions.

The on-surface coupling reactions of terminal alkynes catalyzed by exogenous cupric ions on chemically inert highly oriented pyrolytic graphite (HOPG) surface have been investigated by scanning tunnelling microscopy. In the presence of exogenous cupric ions, diyne-linked nanostructures generated via homocoupling of terminal alkynes are the exclusive products, whereas no coupling reaction occurs for the terminal alkynes on the surface in the absence of the cupric ions, suggesting that exogenous cupric ions are efficient to catalyze the highly chemoselective on-surface reaction of terminal alkynes. The HOPG surface displays a template effect to the growth and alignment of the products on the surface. As a result, 2D arrays of diyne-linked zigzag polymers and 2D diyne-linked porous polymers are fabricated from ditopic monomer 3,6-diethynylcarbazole and tritopic monomer 1,3,5-tris-(4-ethynylphenyl) benzene, respectively. This synthetic strategy combining the high selectivity of cupric ion catalyst as well as the template effect of on-surface synthesis approach could be a general strategy to fabricate diyne-linked nanostructures and nanomaterials on solid surfaces.

Synthesis, structural characterization, and properties of triorganotin complexes of Schiff base derived from 3‐aminobenzoic acid and salicylaldehyde or 2,4‐pentanedione

Six new triorganotin 3‐(salicylideneamino)benzoates (1a–1c) and 3‐(4‐oxo‐2‐penten‐2‐ylamino)benzoates (2a–2c), 3‐(2‐HOC6H4CH=N)C6H4COOSnR3, and 3‐(CH3COCH=C(CH3)NH)C6H4COOSnR3 (R = Ph, a; Cy, b; Bu, c) have been synthesized by one‐pot reaction of 3‐aminobenzoic acid, salicylaldehyde (or 2,4‐pentanedione), and triorganotin hydroxide and characterized by elemental analysis, infrared, and nuclear magnetic resonance (1H, 13C, and 119Sn) spectra. The crystal structures of 1a, 1b, and 2a–2c have been determined by the single crystal X‐ray diffraction. Complexes 1a and 2a exhibit a 44‐membered macrocyclic tetramer and a polymeric zigzag chain, respectively, in which tin atoms show trans‐[C3SnO2] trigonal bipyramidal geometry with the axial positions being occupied by the carboxylate oxygen atom and the phenolic (or ketone) oxygen atom from another ligand. Complex 1b adopts a distorted tetrahedral geometry at tin, and there are two molecules differing in the relative orientation of the carboxylate toward the imino group. Compounds 2a⋅CH3OH, 2b⋅H2O, and 2c⋅H2O are five‐coordinated mononuclear adducts with one coordinated solvent molecule and display different supramolecular organizations in which there are the centrosymmetric R22(16), R42(22), and R64(34) macrocycle motifs formed by the O–H⋅⋅⋅O, N–H⋅⋅⋅O, and C–H⋅⋅⋅O hydrogen bonds. The fluorescence spectrum indicates that the complexes may be explored for potential blue luminescent materials. Compared to cisplatin, these compounds exhibit enhanced cytotoxic efficacy and can be considered as anticancer agents for further study.

Ditopic carboxylate containing zigzag chain polymers with tetrahedral Co(II) and Zn(II) nodes

Two 1D coordination polymers based on tetrahedral cobalt(II) and zinc(II) complex monomers involving terephthalate (1,4-benzenedicarboxylate) dianions as ligand bridges viz., [Co(ta)(DMP)2]n1 and [Zn(ta)(DMP)2.H2O]n2 (ta = terephthalate, DMP = 3,5-dimethylpyrazole) have been synthesized and characterized by elemental analysis, spectroscopic methods as well as by single crystal X-ray diffraction method. Compounds 1 and 2 are chain polymers wherein the polymeric zigzag chains remain linked through intermolecular hydrogen bonds to give rise to robust 3D network structures. Topological analysis of the structure of 2 reveals an underlying net that can be described as 2C1. While the solid state UV–vis–NIR spectrum 2 reflects the tetrahedral coordination geometry around Co(II), thermogravimetric studies indicate that this species retains its 3D network up to about 170 °C. The temperature dependence of the magnetic susceptibility of 1 indicates weak antiferromagnetic interaction among the unpaired spins.

A Molybdenum Trioxide Hybrid Decorated by 3-(1,2,4-Triazol-4-yl)adamantane-1-carboxylic Acid: A Promising Reaction-Induced Self-Separating (RISS) Catalyst.

3-(1,2,4-Triazol-4-yl)adamantane-1-carboxylic acid (tradcH), a heterobifunctional organic ligand in which carboxylic acid and 1,2,4-triazole groups are united through a rigid 1,3-adamantanediyl spacer, was employed for the synthesis of a MoVI oxide organic hybrid. The ligand crystallized from water as tradcH·H2O (1), possessing a two-dimensional hydrogen-bonding network, and from ethanol as a cyclic molecular solvate with the composition (tradcH)3·2EtOH (2). Treatment of tradcH with MoO3 under hydrothermal conditions afforded a new Mo trioxide hybrid, [MoO3(tradcH)]·H2O (3), which was structurally characterized. In 3, the molybdenum atoms form a polymeric zigzag chain of {μ2-O-MoO2}n which is supported by double triazole bridges, while the carboxylic acid termini are left uncoordinated. The coordination environment of the Mo centers appears as distorted cis-{MoN2O4} octahedra. The hybrid exhibits high thermal stability (up to 270 °C) and was employed for a relatively broad scope of catalytic oxidation reactions in the liquid phase. Its catalytic behavior may be compared to a reversible mutation, featuring the best sides of homogeneous and heterogeneous catalysis. The original solid material converts into soluble active species, and the latter revert to the original material upon completion of the catalytic reaction, precipitating and allowing straightforward catalyst separation/reuse (like a heterogeneous catalyst). This catalyst was explored for a chemical reaction scope covering sulfoxidation, oxidative alcohol dehydrogenation, aldehyde oxidation, and olefin epoxidation, using hydrogen peroxide as an eco-friendly oxidant that gives water as a coproduct.

Principles of the Construction of Polymer Structures, Heteronuclear (13C, 15N) CP-MAS NMR, and Thermal Behavior of Heteroleptic Bismuth(III) Complexes of the General Composition [Bi(S2CNR2)2X] (X = NO3, Cl)

The crystalline heteroleptic bismuth(III) complexes, [Bi{S2CN(iso-C4H9)2}2(NO3)] (I) and [Bi{S2CN(C3H7)2}2Cl] (II), are isolated in preparative yields. Both compounds form 1D polymer structures and are characterized by X-ray diffraction analysis (CIF files CCDC nos. 1877115 (I) and 1876364 (II)) and (13C, 15N) CP-MAS NMR spectroscopy. The coordination mode of each of the dialkyldithiocarbamate ligands is S,S′-anisobidentately terminal. The inorganic anions performing the μ2-bridging function participate in the binding of the adjacent metallic atoms to form zigzag polymer chains. A new mode of bismuth(III) binding involving all oxygen atoms (O,O'-anisobidentate coordination to each adjacent bismuth atom) is found for the bridging nitrate groups in compound I. The bismuth atoms in the studied compounds are characterized by the eightfold [BiS4O4] (I) or sixfold [BiS4Cl2] (II) environment. The thermal behavior of the synthesized complexes is characterized by the data of simultaneous thermal analysis, using parallel recording of thermogravimetry and differential scanning calorimetry curves. In both cases, Bi2S3 is the only final product of the thermal transformations of compounds I and II.

The synthesis and crystal structure of bis-[3,3-diethyl-1-(phenyl-imino-κN)thio-urea-κS]silver hexa-fluorido-phosphate.

The structure of the title complex, [Ag(C11H15N3S)2]PF6, has monoclinic (P21/c) symmetry, and the silver atom has a distorted square-planar geometry. The coordination complex crystallized from mixing silver hexa-fluorido-phosphate with a concentrated tetra-hydro-furan solution of N,N-di-ethyl-phenyl-azo-thio-formamide [ATF; systematic name: 3,3-diethyl-1-(phenyl-imino)-thio-urea] under ambient conditions. The resultant coordination complex exhibits a 2:1 ligand-to-metal ratio, with the silver(I) atom having a fourfold AgN2S2 coordination sphere, with a single PF6 counter-ion. In the crystal, however, one sulfur atom from an ATF ligand of a neighboring complex coordinates to the silver atom, with a bond distance of 2.9884 (14) Å. This creates a polymeric zigzag chain propagating along the c-axis direction. The chains are linked by C-H⋯F hydrogen bonds, forming slabs parallel to the ac plane.

Investigating the Impact of Ultrasonic Irradiation Power, Concentrations of Reactant, and Reaction Period on Morphology of Novel Nano Hg(II) Metal–Organic Coordination Polymer

In the present work, using sonochemical method, novel mercury (II) metal–organic supramolecule with nano-rods shape, [Hg(1,10-phen)Cl2]n (1) (1,10-then = 1,10-phenanthroline) was prepared. The impact of the synthesis elements including duration, irradiation power, and concentrations was investigated and enhanced. Nano rods and nano flowers morphologies were obtained by applying diverse sonication time, power and concentration. The samples were categorized via IR spectroscopy, scanning electron microscopy, single crystal X-ray analysis, elemental analysis, X-ray photoelectron spectroscopy and X-ray powder diffraction. Based on the X-ray structure analysis, it was observed that two nitrogen atoms of the “1,10-phen” ligand and four chloride bridging atoms with symmetrical octahedral geometry and a HgN2Cl4 donor set coordinate the Hg(II) atom. A one-dimensional zig-zag polymer is created by the crystal forms. The nearby chains attached to π–π of nearby aromatic circles of “1,10-phen” and other weak interactions. Hence, as a result of the weak interactions, it is possible for the 1D zig-zag arrangement to create a three dimensional metal–organic coordination polymer. Through thermolyzing the compound 1 with oleic acid as a surfactant at the temperature of 180 °C, HgO nanoparticles were obtained. Using SEM, the as-synthesized HgO nanoparticles were further tested in terms of the morphology and size.

The Importance of CH···X (X = O, π) Interaction of a New Mixed Ligand Cu(II) Coordination Polymer: Structure, Hirshfeld Surface and Theoretical Studies

In this study, a new equimolar (1:1:1) mixed ligand Cu(II) polymer, [Cu(IDA)(ImP)]n (1) with iminodiacetato (IDA) and imidazo[1,2-a]-pyridine (ImP) was synthesized and characterized by single crystal X-ray diffraction analysis. X-ray crystallography reveals that compound (1) consists of polymeric zigzag chain along [010] the carboxylate carbonyl oxygen atom by two-fold symmetry screw axis. The solid-state structure is stabilized through C–H···O hydrogen bonds and C–H···π interactions that lead the molecules to generate two-dimensional supramolecular assemblies. The intricate combinations of hydrogen bonds and C–H···π interactions are fully described along with computational studies. A thorough analysis of Hirshfeld surface and fingerprint plots elegantly quantify the interactions involved within the structure. The binding energies associated with the noncovalent interactions observed in the crystal structure and the interplay between them were calculated using theoretical DFT calculations. Weak noncovalent interactions were analyzed and characterized using Bader’s theory of ‘‘atoms-in-molecules’’ (AIM). Finally, the solid-state supramolecular assembly was characterized by the “Noncovalent Interaction” (NCI) plot index.

Synthesis, spectroscopic study, and crystal structure of a new organotin(IV) selenate derivative

Abstract The polymeric organotin(IV) selenate complex [(Me3Sn)3(SeO4)(OH)]n (1) has been isolated as single crystals from the reaction of [(Me2NH2)2SeO4] and Me3SnCl in methanol. In the solid state, compound 1 was characterized by X-ray diffraction analysis, Fourier transform-infrared spectroscopy, and elemental analysis. 1 crystallizes in the orthorhombic system space group Pbca with a=11.0231(2) Å, b=16.3461(3) Å, c=20.9945(4) Å, α=β=γ=90°, V=3782.89(12) Å3, and Z=8. Its structure can be described as a polymeric zigzag chain based on Me3Sn moieties linked by tridentate selenate anions. Pendant (Me3Sn)2OH groups are also connected to the chain, according to a syndiotactic organization, and via Sn-O-Se bonds. Intermolecular OH···O hydrogen bonds and long Se-O···Sn distance interactions promote the association of chains together and lead to the propagation of a three-dimensional network. In addition, the behavior of 1 in solution (methanol) was also studied by multinuclear nuclear magnetic resonance spectroscopy and mass spectrometry.

Crystal polymorphs of 6-[(phenylcarbamoyl)oxy]hexa-2,4-diyn-1-yl isonicotinate.

The title compound, C19H14N2O4, was found to have two crystal polymorphs, in which the molecular structures of the diacetylenic compound are broadly similar. The main structural difference between the polymorphs concerns the intermolecular hydrogen-bonding motifs adopted, namely a one-dimensional zigzag polymer linked by N-H...N(py) (py is pyridine) interactions in polymorph I and a centrosymmetric dimeric motif formed by N-H...O=C interactions in polymorph II. The diacetylene cores of the molecules stack along the a and b axes in polymorphs I and II, respectively. It was found that only the molecular arrangement in polymorph II satisfies Baughman's criterion to afford polydiacetylenes (PDAs) by thermal annealing or irradiation with light. This predicted polymerization activity was confirmed by experiment.

Synthesis, crystal structure and desulfurization properties of zig-zag 1D coordination polymer of copper(II) containing 4-methoxybenzoic acid ligand

ABSTRACTCombustion of fuels containing organosulfur compounds has resulted in the emission of sulfur oxides (SOx) into the atmosphere, therefore, causing serious environmental and health hazards. Herein, slightly distorted octahedral zig-zag 1D coordination polymer of copper(II) [Cu(4-mba)2(H2O)3] was synthesized by reacting copper sulfate pentahydrate with a carboxylate-containing ligand (H-4mba = 4-methoxybenzoic acid) and employed for sulfur compound uptake. The ligand coordinates to the copper(II) atom via two pairs of deprotonated ligating atoms (carboxylate oxygens) and two water molecules. Structural characterization also reveals that interplay of O–H···O, N–H···O, C-H···O and C–H···π interactions between lattice and coordinated water and ligands significantly contribute to the crystal packing leading to the formation and strengthening of three-dimensional supramolecular assembly. The complex, [Cu(4-mba)2(H2O)3], show potential for desulfurization of fuel with an observed adsorption capacity of 9.6 mg/g at 32°C for 6 h. DFT calculations further revealed a transfer of electron sulfur-containing compounds and the complex, [Cu(4-mba)2(H2O)3], thus leading to a stronger pi–pi interaction.

Catena-Poly[[[2,4-dichloro-6-{[(2-hydroxyethyl)imino]methyl}phenolato-κ3N,O,O']-copper(II)]-μ-chlorido]monohydrate]: Synthesis, structural, spectroscopic and luminescent properties

ABSTRACTA new chloride bridged polymeric Cu(II) complex, [Cu(HL)(μ-Cl).H2O]n, 1, (H2L = 2,4-dichloro-6-{[(2-hydroxyethyl)imino]methyl}phenol) has been synthesized and characterized by elemental-spectral analysis, crystal structure analysis and photoluminescence measurements. The Copper(II) atom is five-coordinate in a slightly distorted square-pyramidal geometry (τ = 0.085), with one N and two O atoms of the Schiff base ligand and one Cl atom defining the basal plane and a symmetry-related Cl atom occupying the apical position. The bridging Cl atom lies in apical position for one Cu(II) ion and basal for the other, and it makes this structural arrangement unusual. The linked moieties form polymeric zigzag chains running along the c axis. This zigzag chains connect each other with intramolecular and intermolecular O–H···O hydrogen bonds, which form 3D structure through π−π interactions. Furthermore, the photoluminescence properties of H2L and 1 were investigated, they exhibit unique bright green visible emissions in the solid state, under the excitation of 349 nm UV light. The strong luminescence emission of them makes 1 a potentially useful photoactive material in photo-physical chemistry.

Ultrasonic-assisted synthesis and the structural characterization of novel the zig-zag Cd(II) metal-organic polymer and their nanostructures

A sonochemical method was used to synthesize nano-rods of a novel cadmium(II) metal-organic coordination polymer, [Cd(p-2yeinh)(NO2)]n (1) (p-2yeinh = pyridin-2-yl ethylidene-isonicotinohydrazide). The effect of the synthesis parameters such as time, concentrations and irradiation power has been studied and optimized. It was shown that the thickness of rods has changed from 27 nm to 45 nm. The compounds were characterized by scanning electron microscopy (SEM), elemental analysis, IR spectroscopy, X-ray powder diffraction (XPRD), and single crystal X-ray analysis. The X-ray structure analysis revealed that the Cd(II) atom is coordinated by one oxygen and three nitrogen atoms from two p-2yeinh ligands and two oxygen atoms of single nitrite anion with a CuN3O3 donor set with distorted octahedral geometry. The crystal taking the form of a one-dimensional zig-zag polymer. The adjacent chains connected by π–π of adjacent aromatic rings of p-2yeinh and other weak interactions. Consequently, the weak interactions also allow the 1D zig-zag structure to form a 3D metal-organic coordination polymer. CdO nanoparticles were prepared by thermolysis of compound 1 at 180 °C with oleic acid as a surfactant. The average diameter of the nanoparticles was estimated by XPRD to be 23 nm. The morphology and size of the prepared CdO nanoparticles were further studied using SEM.

A Suite of Sterically-Demanding Hybrid Alkyl/Cyclopentadienyl Ligands

The hybrid alkyl/cyclopentadienyl “constrained-geometry” proligands (Me3Si)2CH{SiMe2(C5H5)}, (Me3Si)2CH{SiMe2(C5Me4H)} and (Me3Si)2CH{SiMe2(C5H4-3-SiMe3)} were synthesized by the reaction of the bromosilane (Me3Si)2CH(SiMe2Br) with the corresponding lithium cyclopentadienides. Metalation of these proligands with an excess of MeK gives access to the corresponding dipotassium salts [(Me3Si)2C{SiMe2(C5H4)}]K2(OEt2)0.5, [(Me3Si)2C{SiMe2(C5Me4)}]K2(OEt2), and [[(Me3Si)2C{SiMe2(C5H3-3-SiMe3)}]K2(C6H6)]2·2C6H6 after recrystallization. Similarly, the reaction between the phosphine–borane-substituted chlorosilane (Me3Si)CH{PMe2(BH3)}(SiMe2Cl) and [C5Me4H]Li gives the proligand (Me3Si)CH{PMe2(BH3)}{SiMe2(C5Me4H)}, which reacts with 2 equiv of PhCH2K to give the dipotassium salt [(Me3Si)C{PMe2(BH3)}{SiMe2(C5Me4)}]K2(THF). X-ray crystallography revealed that the dipotassium salts of these hybrid ligands crystallize as zigzag polymers or three-dimensional networks. The suitability of the dipotassium salts as ligand tr...

Cd(II) coordination polymers based on expanded N,N′-heteroaromatic donor ligands

The isomeric N donor linkers bis(pyridin-4-ylmethylene)naphthalene-1,5-diamine (L1) and bis(pyridin-3-ylmethylene)naphthalene-1,5-diamine (L2) have been used with acetate and iodide as co-ligands to generate four new cadmium(II) coordination polymers. [CdL1(OAc)2]n (1), [CdL1(I)2]n (2), [CdL2(OAc)2]n (3) and [CdL2(I)2]n (4) were characterized by elemental analysis, X-ray powder diffraction, IR spectroscopy, thermal analysis and single crystal X-ray diffraction. In line with the concept of crystal engineering, their structures share common motifs: the heteroaromatic linkers generate chains, subtending Cd⋯Cd distances consistent with their N donor arrangement. The co-ligands control the coordination number of the Cd(II) cations and interchain connectivity: The acetate moieties either adopt bridging and chelating or exclusively bridging modes and crosslink essentially linear chains based on octahedral metal centers; in the former case, the ladder-like one-dimensional ribbon 1 is generated, whereas the latter connectivity results in the two-dimensional layer structure 3. In contrast, iodide acts as terminal ligand towards tetrahedral Cd(II), and hence 2 and 4 are single-stranded 1D zig-zag polymers. In comparison to the uncoordinated heteroaromatic L1 and L2, the Cd coordination polymers show slightly red-shifted luminescence spectra of significantly higher intensity due to the more rigid arrangement of the π systems.

Synthesis and characterization of new Ag(I) coordination networks based on saccharinate and bis(isopropylimidazole) ligands exhibiting very close C–H⋯Ag interactions

Two Ag(I) coordination networks, formulated as [Ag(sac)(μ-bisopib)]n (1) and [Ag(sac)(μ-pbisopix)]·H2O (2), have been synthesized based on the bis(isopropylimidazole) ligands 1,4-bis(2-isopropyl-1H-imidazol-1-yl)butane (bisopib) and 1,4-bis((2-isopropyl-1H-imidazol-1-yl)methyl)benzene (pbisopix), respectively, along with saccharinate (sac) ligands. All the complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction studies. The X-ray crystallographic studies of 1 and 2 revealed that the Ag(I) ions are μ-bridged by the bis(isopropylimidazole) derivative ligands to generate 1D zig-zag polymer and dinuclear structures, respectively. As far as we know, complex 1 shows the closest C–H⋯Ag interaction distance among similar literature examples. In complex 1 adjacent 1D coordination polymers are further joined by C–H⋯O hydrogen bonds and π⋯π interactions, generating a 3D supramolecular network. The C–H⋯O hydrogen bonds and C–H⋯π interactions play a crucial role in the architecture of the 3D network of complex 2. Thermal decompositions and photoluminescent properties of the Ag(I) complexes are also discussed herein.

Three coordination polymers constructed from 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid: Synthesis, crystal structure and properties

Three new coordination polymers, namely, {[Co2(TPA)(μ3-O)3]·0.5DMA}n (1), {[Co(H2TPA)(bibp)(H2O)3]·H2O}n (2) and {[Cd3(TPA)2(phen)4]·4H2O}n (3), (H3TPA = 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid, bibp = 4,4'-bis(imidazolyl)biphenyl, phen = 1,10-phenanthroline and DMA = N,N-dimethylacetamide), have been synthesized under solvothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction analysis. Polymer 1 exhibits a three-dimensional (3D) structure constructed from 5-connected secondary building units (SBUs) [Co3(μ3-O)] and 3-connected H3TPA ligands. Polymer 2 has a 1D zigzag polymer chain connected by H3TPA and bibp ligands. Polymer 3 features an unusual 3D framework with a (3,4,2)-connected {4; 6;8}{4; 62;83} topology. Moreover, the thermal stabilities of 1–3 and photoluminescence properties of 3 have been investigated. Magnetic susceptibility measurements indicate that polymers 1–2 display antiferromagnetic exchange properties.