Organic-inorganic Hybrid Networks Research Articles

Two Cd(II) coordination polymers based on asymmetrical Schiff-base ligand with five- and six-membered N-containing heterocyclic rings: Synthesis, crystal structures and luminescent properties

Two cadmium inorganic–organic hybrid coordination polymers [CdL(SCN)2]n (1) and [CdLI2]n (2), have been synthesized and characterized by IR spectroscopy, elemental analysis, XRPD, thermogravimetric (TG) analyses and X-ray crystallography, where L is 4-(pyridine-4-yl)methyleneamino-1,2,4-triazole. Asymmetrical Schiff-base ligand L acts as a bidentate bridging ligand to bind two Cd(II) centers through two terminal Ntriazolyl and Npyridyl donors in polymers 1 and 2. Polymer 1 displays a new 3D inorganic–organic hybrid network generated through the coordination interactions between Cd-(1,3-μ-SCN−) 2D inorganic sheets and bidentate bridging ligands. The structure of polymer 2 is a 3D chiral supramolecular framework which contains helical chains on 21 axis. Each Cd(II) center is coordinated by two ligands and two I− donors to attain a distorted tetrahedral environment. The luminescent properties of polymers 1 and 2 were investigated in the solid state at room temperature.

Two copper coordination polymers with pyridine imine-based ligand: Synthesis, crystal structure and luminescent properties

Two new copper coordination polymers [CuI2L(SCN)2]n (1) and {[CuIIL2(NO3)2]·2H2O}n (2), have been synthesized and characterized by IR, elemental analysis, XRPD, TG technique and X-ray crystallography, where L is N,N′-bis-(1-pyridin-4-yl-ethylidene)-hydrazine. Polymer 1 displays a new 3D inorganic–organic hybrid network generated through the coordination interactions between 2D inorganic sheets Cu(I)-(1,1,3-μ-SCN−) and bidentate bridging ligands L with two terminal monodentate pyridyl N donors. Each Cu(I) center adopted a distorted tetrahedral environment. The structure of polymer 2 is a 2D layer network containing tetrametallic quadrangular ring units [CuII4L4], in which each copper(II) atom is linked by four terminal monodentate pyridyl N-donors from four twist ligands and two oxygen atoms from two NO3−. The luminescent properties of polymers 1 and 2 were investigated in the solid state at room temperature.

Assembly of four d10-metal inorganic–organic hybrid coordination polymers based on bipyrazine imine-based ligand: Synthesis, crystal structures and luminescent properties

Four new inorganic–organic hybrid coordination polymers {[Ag2L(NO3)2]·H2O}n (1), [Ag2L(SCN)2]n (2), [CdL(SCN)2]n (3), and [CdLI2]n (4) have been synthesized and structurally characterized by IR spectroscopy, thermogravimetric (TG) analyses and complete single crystal structure analyses, where L is 2,5-bis(pyrazinyl)-3,4-diaza-2,4-hexadiene. The structure of polymer 1 is a 3D coordination framework containing Ag-(μ-NO3−) inorganic bridging units, in which each L coordinates four silver atoms through two pyrazinylimine chelate units and two terminal monodentate pyrazinyl N donors. Polymer 2 displays a new 3D inorganic–organic hybrid network through the coordination interactions between Ag-(1,1,3-μ-SCN−) inorganic 2D sheets and bidentate bridging ligands with two terminal monodentate pyrazinyl N donors. Bidentate bridging ligands link 1D inorganic chains Cd-(1,3-μ-SCN−) system for 3 and Cd-(μ-I−) system for 4 to form a similar two-dimensional layer network. The luminescent properties of polymers 1–4 were investigated in the solid state at room temperature.

A novel copper molybdate inorganic–organic hybrid network synthesized by in-situ generation of pyridine-4-carboxylic ion from 1,3-bis(4-pyridyl) propane precursor

Abstract A novel three-dimensional copper molybdate [CuI(PCI)Mo2VO5] (1) (PCI = pyridine-4-carboxylic ion) has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG, XPS and single-crystal X-ray diffraction analysis. In compound 1, the {Mo2VO5N}n dimeric chains alternately connect to copper chains via corner-sharing mode to form the bimetallic{CuIMo2VO5N}n layer. These adjacent layers are linked by PCI ligands to generate a 3D framework. Interestingly, the PCI ligand is generated from the 1,3-bis(4-pyridyl) propane precursor via catalytic oxidation of polyoxomolybdate and copper cation. The electrochemical and electrocatalysis behavior of compound 1 have been studied in detail.

The anomalous behavior of physical-chemical parameters during polymerization of organic-inorganic polymer systems based on reactive oligomers

AbstractDependencies of physical-chemical characteristics on structure development during polymerization of organic-inorganic systems (OISs) have been investigated. The non-monotonic behavior of the physical parameters has been found. This effect was explained by complicated structure of OISs, which consists of two interpenetrating hybrid organic-inorganic networks, which are characterized by different rate of the structure formation.

Novel triazole functional sol–gel derived inorganic–organic hybrid networks as anhydrous proton conducting membranes

In this work, novel inorganic–organic hybrid networks were prepared to obtain anhydrous proton conducting membranes for fuel cells. 3-glycidoxypropyl trimethoxy silane (GPTMS) was functionalized with 1H-1,2,4-triazole (Tri) and 3-aminotriazole (ATri) via ring opening of the epoxide ring and then sol–gel polymerization was performed to produce triazole containing silane networks abbreviated as Si–Tri and Si–ATri. In addition during sol–gel process trifluoromethane sulfonic acid (TA) was introduced into the matrix with several stoichometric ratios. Fourier transform infrared spectroscopy (FT-IR) confirmed the tethering of the Tri and ATri into the silane compound and the sol–gel reaction. Thermogravimetry analysis (TGA) showed that the membranes are thermally stable up to 200 °C. Differential scanning calorimeter (DSC) verified the softening effect of the dopant. The morphology of the membranes was analyzed with SEM images. The proton conductivity of these novel silane networks were studied by dielectric-impedance spectroscopy. Although proton conductivity of these membrane electrolytes depends on the acid ratio, the membrane without dopant produced a proton conductivity of 8.7 × 10−5 S/cm at 150 °C in dry state. The conductivity isotherms show Vogel–Tamman–Fulcher (VTF) behavior which implies the coupling of the charge carriers with the segmental motion of the polymer chains. A maximum proton conductivity of 8.9 × 10−4 S/cm was obtained for the sample Si–TriTA1 in the anhydrous condition.

Correction to “Conformal Organic-Inorganic Hybrid Network Polymer Thin Films by Molecular Layer Deposition using Trimethylaluminum and Glycidol”

Correction to “Conformal Organic-Inorganic Hybrid Network Polymer Thin Films by Molecular Layer Deposition using Trimethylaluminum and Glycidol”

Conformal Organic−Inorganic Hybrid Network Polymer Thin Films by Molecular Layer Deposition using Trimethylaluminum and Glycidol

Growing interest in nanoscale organic-inorganic hybrid network polymer materials is driving exploration of new bulk and thin film synthesis reaction mechanisms. Molecular layer deposition (MLD) is a vapor-phase deposition process, based on atomic layer deposition (ALD) which proceeds by exposing a surface to an alternating sequence of two or more reactant species, where each surface half-reaction goes to completion before the next reactant exposure. This work describes film growth using trimethyl aluminum and heterobifunctional glycidol at moderate temperatures (90-150 °C), producing a relatively stable organic-inorganic network polymer of the form (-Al-O-(C(4)H(8))-O-)(n). Film growth rate and in situ reaction analysis indicate that film growth does not initially follow a steady-state rate, but increases rapidly during early film growth. The mechanism is consistent with subsurface species transport and trapping, previously documented during MLD and ALD on polymers. A water exposure step after the TMA produces a more linear growth rate, likely by blocking TMA subsurface diffusion. Uniform and conformal films are formed on complex nonplanar substrates. Upon postdeposition annealing, films transform into microporous metal oxides with ∼5 Å pore size and surface area as high as ∼327 m(2)/g, and the resulting structures duplicate the shape of the original substrate. These hybrid films and porous materials could find uses in several research fields including gas separations and diffusion barriers, biomedical scaffolds, high surface area coatings, and others.

Fabrication and responsive behaviour of Quantum Dot/PNIPAM micropatterns obtained by template copolymerization in water

A facile method for the fabrication of Quantum Dot/poly(N-isopropylacrylamide) (QD/PNIPAM) micropatterns on glass is presented. Water-soluble QDs functionalized with polymerizable methacrylic groups effectively copolymerize with N-isopropylacrylamide monomer resulting in stable hybrid organic–inorganic networks. The patterns display temperature and pH responsive luminescence behaviour.

Preparation and Properties of UV Curable Silica Coatings from MPTMS and TEOS

UV curable 3-(trimethoxysilyl) propyl methacrylate MPTMS modified silica hybrid coating was prepared through sol-gel process from TEOS and MPTMS in acid medium for different ratios between TEOS and MPTMS. The structure of the hybrid coating and the formation of inorganic-organic hybrid networks were studied by FT-IR. It was found that the organic networks were formed by the polymerization of C=C bonds at 1638 cm-1. The influences of the photoinitiator content and the curing time on the curing degree of the mixture system were investigated. The results showed that the optimal photoinitiator content was 3%, and curing time was 180 s. The thermal stability of the UV cured coating was investigated by TG-DTA. The results showed that the contents of low-molecular compounds such as H2O, CH3OH, etc. were decreased in cured coatings with the increasing of the MPTMS concentration, thus significantly decreasing of the thermal weight-loss at temperature lower than 400°C.

Nanocrystalline TiO2 Thin Films Fabricated Via a Polyelectrolyte Multilayer‐Assisted Sol–Gel Reaction

Nanostructured anatase titanium dioxide (TiO2) thin films were fabricated with an in situ, sol–gel process in a self‐assembled, polyelectrolyte multilayer (PEM) template. Because the PEM template is formed by the sequential adsorption of appositively charged, weak polyelectrolytes, polyacrylic acid, and polyallylamine, it contains nonionized carboxylic groups that are able to react with the inorganic precursor, resulting in the formation of an inorganic–organic hybrid network. After annealing, nanocrystalline TiO2 films with a controlled surface morphology, crystallite size, and a thickness on the nanometer scale were obtained. The average TiO2 crystallite size was approximately 10 nm. The surface morphology and the roughness of the nanocrystalline films were evaluated by field‐emission scanning electron microscopy and atomic force microscopy. UV‐vis spectroscopy was used to establish the optical parameters of the nanocrystalline TiO2 films. The as‐fabricated, nanostructured TiO2 films showed high absorption in the UV region and the controlled transmission of visible light.

Effect of DMPA-Clay-POSS Content on Thermal and Mechanical Properties of Nanostructured Ionomeric Polyurethanes

Two series of ionomeric waterborne polyurethane (WBPU)/POSS-clay hybrid nanocomposites were synthesized using various amounts of a diol-functionalized polyhedral oligomeric silsesquioxane (POSS)/clay (Cloisite 15A) component with two different 2,2-dimethylol propionic acid (DMPA) contents (13.58 mole% and 23.89 mole%). The Tg of WBPU/POSS-clay hybrid nanocomposite was shifted towards higher temperatures in comparison to virgin WBPU and WBPU/clay nanocomposites. The thermal stability of the investigated WBPU/POSS-clay hybrid nanocomposites also dramatically improved compared to pristine WBPU and WBPU/clay nanocomposites. The higher Young's modulus of the WBPU/POSS-clay hybrid nanocomposites as a function of optimal POSS content suggests that the organic-inorganic hybrid networks are significantly reinforced by the inclusion of POSS.

Microencapsulation of an acrylate monomer in silica particles by sol–gel process

The sol–gel synthesis strategies combined with the templated growth of organic–inorganic hybrid networks provide access to an immense new area of innovative multi-functional advanced materials. One possible way to prepare such new advanced materials is to encapsulate liquid active agents (such as monomers, dyes, catalysts and hardeners) in microcapsules. Silica microcapsules of tetraethylortosilicate (TEOS) and 3-(trimethoxysilyl)propyl methacrylate (MPTS) were prepared in a precursor-monomer/NH4OH water microemulsion system. Trimethylolpropane triacrylate (TMPTA)—a trifunctional monomer useful in manufacturing of coatings, inks and adhesives—and a corresponding photoinitiator (DAROCUR 1173) were entrapped inside the obtained microcapsules. MPTS was used to increase compatibility between TMPTA and the sol–gel precursors. As stability agent we added a “home made” product resulted from functionalization of poly (ethylene glycol) methyl ether (MPEG) with (3-isocyanatopropyl) triethoxysilane (NCOTEOS). Were obtained microcapsules containing incorporated monomer and having average particle size in range of 0.5–50 μm. Thermal analysis, morphology study and the increase of the silica microcapsules average diameter, measured by DLS technique confirm the monomer encapsulation.

Charge interaction of low generation dendrimers during zeolite formation

A Small Angle X-ray Scattering (SAXS) investigation has been performed to study the self-assembly process generated by the addition of a low generation G1.5 polyamidoamine dendrimer during the zeolite LTA formation process. The presence of a condensed cationic Na + charge all around the dendrimers, which is responsible for the intense electrostatic interparticle interaction potential, stimulate the condensed growth of the zeolitic phase onto the dendrimer substrate. The screening produced by the zeolite grown on the dendrimer surface promote also an entanglement process between the primary units with the formation of large clusters as evidenced by Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) microprobe spectroscopy experiments. The current investigation emphasizes the potentials of using hybrid organic–inorganic networks in the synthetic construction of functional materials with high-order structures for application in material science and biotechnology.

ChemInform Abstract: Arylsilsesquioxane Gels and Related Materials. New Hybrids of Organic and Inorganic Networks.

Molecular building blocks for the preparation of amorphous hybrid organic-inorganic network materials have been synthesized. Hydrolysis and condensation of bis(triethoxysilyl)aryl 1-4 and -ethynyl 5 monomers results in formation of aryl- and ethynyl-bridged polysilsequioxanes in the form of xerogels. The gels were glasslike materials composed of uniform aggregate of particles between 50 and 80 nm in diameter. Atomic force microscopy was used to examine the fine grained aggregate characteristics of phenyl-bridged polysilsesquioxane

Materials for capacitive carbon dioxide microsensors capable of operating at ambient temperatures

The responses of alkylamine functionalized organic bridged polysilsesquioxanes on chemicapacitive sensors to carbon dioxide (CO2) are described operating at temperatures ranging from 15 to 50°C. These hybrid organic–inorganic network materials were synthesized by the sol–gel polymerization of a mixture of a matrix monomer and functional monomer at various ratios followed by aging and ink-jet deposition of the sol on each capacitive sensor. During exposure of the sensor to known concentrations of analyte, the material’s capacitance was measured. From these changes in capacitance, detection limits ranging from 40 to 100 ppm were calculated. Furthermore, a correlation was observed with increasing length of the alkyl chain in the amine monomer correlating with an increase in CO2 sensitivity and a decrease in water sensitivity. These materials offer a new method for CO2 detection for building control systems or other low-power applications using low operating temperatures.

A red luminescent organic–inorganic hybrid network with double-stranded zigzag [Cu4I4]n chains

Abstract A novel red luminescent coordination polymer, [Cu2I2(bmt)]n·nDMF (1), was synthesized from the solution reaction of CuI and heterocyclic thione ligand, benz-1,3-imidazole-2-thione (bmt). Single-crystal analysis shows that its unusual organic–inorganic hybrid framework built-up from the distorted double-stranded zigzag [Cu4I4]n chains with organic bmt ligands. Emission properties of 1 in solid state at room temperature and 10 K were investigated.

Construction of acetate-bridged dicopper(II) hybrid organic–inorganic networks with calix[4]arene-derived nitrogenous ligands

The reactions of mono-, bis- and tetrapicolyl-p-tert-butylcalix[4]arene derivatives functionalised in the phenolic positions (L 1 –L 4 ) with copper(II) acetate resulted in the formation of discrete complexes or extended coordination polymers. The centrosymmetric dimer [Cu2(μ-O2CCH3)4(L 1 )2] 1, obtained with monodentate L 1 , has square pyramidal coordination around the copper centres and a cone conformer of monopicolyl-calix[4]arene acting as an axial ligand, with a molecule of acetonitrile hosted within its cavity. The potentially bidentate L 2 acts as a monodentate ligand, affording the complex [Cu2(μ-O2CCH3)4(L 2 )2] 2, which based on spectroscopic and combustion analysis data has a similar coordination sphere around Cu(II). Compound L 3 bridges two dicopper units in the coordination polymer [Cu2(μ-O2CCH3)4(μ-L 3 )] n 3, with the calixarene hosting a molecule of tetrahydrofuran. Finally, compound L 4 reacts with 4 equivalents of copper(II) acetate, presumably generating a two-dimensional coordination polymer formulated as [{Cu2(μ-O2CCH3)4}2(L 4 )] 4.

Synthesis, structure and properties of cross-linked R(SiO 1.5)/SiO 2 (R = 3-glycidoxypropyl) porous organic inorganic hybrid networks dried at ambient pressure

Highly porous organic inorganic hybrid networks have been prepared from tetraethoxysilane (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) precursors by drying at ambient pressure. Hydrolysis–condensation reactions of the alkoxy groups on the precursors provide the inorganic network and polymerization of the epoxy group on GPTMS, the organic network. The effects of varying the molar ratios, water/OR, and TEOS/GPTMS (precursor ratio) on the gel structure were investigated. Infrared spectroscopy, thermal analysis, nitrogen adsorption measurements, and tunneling electron microscopy were used to characterize the structure and porosity features of the hybrids. At low precursor ratios, the organic networking is characterized by highly cross-linked polymer chains of low molecular weight and at high precursor ratios it consists of mainly linear chains of high molecular weight. Organic networking reinforces the inorganic network at high precursor ratios and the monoliths effectively withstand the stress produced during drying at ambient pressure. But as the proportion of the organic precursor increases, there is a higher shrinkage of the gel network, increasing the density of the dried gel. Variation in precursor ratio affects the volume of larger pores, while varying water content influences the volume of smaller pores. Monolithic gels with low shrinkage and density could be prepared through ambient pressure drying by this method.

Synthesis, structure and magnetic property of the first 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands

Abstract An unprecedented 2-D organic–inorganic hybrid sandwich-type polyoxotungstate containing O-donor organic ligands [DMAH]4{[Mn(DMF)4]2[Mn4(DMF)2(α-B-HPW9O34)2]} (1) (DMA = dimethylamine, DMF = N,N-dimethylformamide) has been solvothermally synthesized and characterized by IR, UV spectra and X-ray single-crystal diffraction. The 2-D organic–inorganic hybrid network of 1 is built by tetra-MnII substituted sandwich-type polyoxotungstates [Mn4(DMF)2(α-B-HPW9O34)2]8− and [Mn(DMF)4]2+ cation bridges, which displays the common 2-D (4,4) topological net. It should be noted that the major difference between [Mn4(DMF)2(α-B-HPW9O34)2]8− in 1 and the reported [Mn4(H2O)2(α-B-PW9O34)2]10− is that two DMF ligands substitute two H2O ligands on the Mn4O16 unit located in the sandwich belt. Magnetic susceptibility measurement indicates the occurrence of antiferromagnetic coupling interaction within MnII ions.