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Inorganic Network (inorganic + network)
Selected AbstractsHybrid Magnetic Materials Based on Nitroxide Free Radicals and Extended Oxalato-Bridged Bimetallic NetworksEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2005Antonio Alberola Abstract A series of hybrid organic-inorganic magnets of formula p -rad[MIICr(ox)3] [M = Mn (1), Co (2), Ni (3), Zn (4)] and m -rad[MIICr(ox)3] [M = Mn (5), Co (6)], in which N -methylpyridinium cations bearing a nitronyl nitroxide moiety in positions 3 (m -rad) or 4 (p -rad) of the pyridine ring coexist with the 2D honeycomb-like oxalato-bridged bimetallic lattice, has been prepared and studied by AC and DC magnetic susceptibility measurements and EPR spectroscopy. In general, the physical properties of these magnets are not altered significantly by the insertion of the nitronyl nitroxide radicals although these paramagnetic molecules seem to interact weakly with the inorganic network as demonstrated by EPR spectroscopy. Some differences can also be observed between the p -rad and m -rad series, i.e. m -rad derivatives have smaller values for the critical temperatures and coercive fields. We also report on the X-ray crystal structures and magnetic properties of p -rad[Mn(H2O)Cr(ox)3]·2H2O (7) and m -rad[Mn(H2O)2Cr(ox)3]·2H2O (8), two extended oxalato-bridged compounds with new topologies. Compound 7 is antiferromagnetic and its structure is a 3D achiral lattice in which zigzag ferromagnetic MnCr chains (J/k = +0.8 K) are interconnected to form hellicoidal hexagonal channels with the cationic free radicals residing in the free space. Compound 8, however, exhibits a ladder-like structural pattern with competing magnetic interactions and paramagnetic behaviour down to low temperatures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Synthetic Strategies for Hybrid Materials to Improve Properties for Optoelectronic Applications,ADVANCED FUNCTIONAL MATERIALS, Issue 14 2008Olga García Abstract We report, for the first time to the best of our knowledge, a systematic study to relate the laser action from BODIPY dyes, doped into monolithic hybrid matrices, with the synthetic protocols of the final materials prepared via sol-gel. To this aim, the influence of both the hydrolysis time, increased in a controlled way, and the nature of the neutralization agent (pyridine, 3-amino-propyltriethoxy-silane (APS), N -[3-(trimethoxysilyl)propyl]-ethylene diamine (TSPDA), and N1 -[3-(trimethoxysilyl)propyl]- diethylene triamine (TSPTA) on the laser action of PM567, incorporated into hybrid matrices based on copolymers of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), with methyltriethoxysilane (TRIEOS) as inorganic precursor, was analyzed. The presence of the amine-modified silane TSPDA as neutralization agent, which is able at the same time to be anchored to the inorganic network enhancing the inorganic-organic compatibility through the matrix interphase, and utilization of hydrolysis times lower than 10 minutes, increased significantly the lasing efficiency and photostability of dye. The extension of this study to the laser behavior of BODIPY dyes embedded in other different hybrid materials based on hydrolyzed-condensed copolymers of MMA with 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) in a 1/1 volumetric proportion, validates the generalization of the above conclusions, which provide guides for the optimization of the synthesis of organic-inorganic hybrid materials with optoelectronic innovative applications independently of their composition. [source] Organic,Inorganic Interactions in Poly(trimethylene carbonate),Titania HybridsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 21 2009Elisa Cortecchia Abstract Polycarbonate,titania hybrids have been synthesized by a sol,gel reaction, starting from poly(trimethylene carbonate) (PTMC) and titanium isoproproxide in different ratios. PTMC with a given chain length was obtained by ring opening polymerization. FT-IR spectra reveal the presence of TiOC covalent bonds between organic and inorganic phases, and their number increases with increasing inorganic phase content. Solvent extractions show that hybrid soluble fraction contains low PTMC chains with isopropoxide ends, which suggests that TiOC bond formation is mainly promoted by transesterification reactions of isopropyl alcohol onto the polymer chain, catalyzed by Ti compounds. Hybrid thermal properties reflect the combined effect of the decrease of PTMC molecular weight and of bond formation between PTMC and the inorganic network. The nanometric dimension of the TiO2 domains, confirmed by atomic force microscopy, provides optically transparent hybrids. [source] Organic,inorganic hybrid membranes prepared from the sol,gel process of poly(butyleneadipate- co -terephthalate) and TiO2POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2009Chien-Hong Lin Abstract Organic,inorganic hybrids based on poly(butyleneadipate- co -terephthalate)/titanium dioxide (PBAT/TiO2) hybrid membranes were prepared via a sol,gel process. The PBAT/TiO2 hybrid membranes were prepared for various PBAT/TiO2 ratios. The resulting hybrids were characterized with a morphological structure, hydrophilicity, biodegradability, and thermal properties. The results showed that macrovoids underwent a transition into a sponge-like membrane structure with the addition of TiO2. After sol,gel transition, a strong interaction between the inorganic network and polymeric chains led to an increase in glass transition temperature (Tg), thermal degrading temperature, and hydrophilicity, and hence a higher biodegradability. According to X-ray diffraction measurements of the crystal structure of the hybrid, the presence of TiO2 did not change the crystal structure of PBAT. TiO2 networks are uniformly dispersed into the PBAT matrix and no aggregation of TiO2 networks in the hybrid membranes was observed through the small angle X-ray scattering measurements. Thus, the sol,gel process of PBAT and TiO2 can be used to prepare a hybrid with higher application temperature and faster biodegradation rate. Copyright © 2008 John Wiley & Sons, Ltd. [source] Sodium tris(glycinium) bis(hexafluorosilicate) glycine trisolvateACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2007Moolya B. Narayana The title compound, Na+·3C2H6NO2+·2SiF62,·3C2H5NO2, arose from an unexpected reaction of glycine and HF with the glass container. It is an unusual hybrid organic,inorganic network built up from chains of vertex-sharing NaF4O2 and SiF6 octahedra. A pair of glycinium/glycine molecules bridges the chains into a sheet via a centrosymmetric O...H...O link. The other organic species interact with the network by an extensive N,H...F hydrogen-bond network, including bifurcated and trifurcated bonds. Finally, an extremely short C,H...O interaction (H...O = 2.25,Å) is seen in the crystal structure. The Na atom has site symmetry . [source] Low loss second-order non-linear optical crosslinked polymers based on a phosphorus-containing maleimidePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 10 2004Chih-Ping Chen Abstract A series of crossslinked organic and organic/inorganic polymers based on maleimide chemistry have been investigated for second-order non-linear optical (NLO) materials with excellent thermal stability and low optical loss. Two reactive chromophores (maleimide-containing azobenzene dye and alkoxysilane-containing azobenzene dye) were incorporated into a phosphorus-containing maleimide polymer, respectively. The selection of the phosphorus-containing maleimide polymer as the polymeric matrices provides enhanced solubility and thermal stability, and excellent optical quality. Moreover, a full interpenetrating network (IPN) was formed through simultaneous addition reaction of the phosphorus-containing maleimide, and sol-gel process of alkoxysilane dye (ASD). Atomic force microscopy (AFM) results indicate that the inorganic networks are distributed uniformly throughout the polymer matrices on a nano-scale. The silica particle sizes are well under 100,nm. Using in situ contact poling, the r33 coefficients of 2.2,17.0,pm/V have been obtained for the optically clear phosphorus-containing NLO materials. Excellent temporal stability (100°C) and low optical loss (0.99,1.71,dB/cm; 830,nm) were also obtained for these phosphorus-containing materials. Copyright © 2004 John Wiley & Sons, Ltd. [source] | |||||||||||||