Synthesis and optical properties of σ–π conjugated organic–inorganic hybrid gels

Naga, Naofumi; Nagino, Hitomi; Iwashita, Midori; Miyanaga, Tomoharu; Furukawa, Hidemitsu

doi:10.1002/pola.27571

Cited by 3 publications

(2 citation statements)

References 21 publications

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“…We have been developed joint‐liker type gels, which are formed by addition reactions of multifunctional symmetrical molecules as joint and bifunctional molecules as linker in some solvents. The joint‐liker type gels formed homogeneous network structure, and their mesh size could be controlled by the length of the linker molecules . The mesh of the network structure was usable for isolate incorporation of small molecules .…”

Section: Introductionmentioning

confidence: 99%

Synthesis and properties of multifunctional thiol crosslinked gels containing disulfide bond in the network structure

Naga

Moriyama

Furukawa

2017

J. Polym. Sci. Part A: Polym. Chem.

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Joint crosslinked gels containing disulfide linkage have been synthesized by oxidation reaction of multi‐functional thiol monomers, trimethylolpropane tris(3‐mercaptopropionate), tris‐[3‐mercaptopropionyloxy‐ethyl]‐isocyanurate, pentaerythritol tetrakis (3‐mercaptopropionate), and dipenta‐erythritol hexakis (3‐mercaptopropionate) in dimethyl sulfoxide (DMSO). Both the oxidation reactions with DMSO at 85 °C and Albright‐Goldman oxidation in the presence of acetic anhydride at 50 °C yielded the corresponding gels. The oxidation reaction with DMSO showed higher reaction conversion than that with Albright‐Goldman oxidation. Network structure of the gels was quantitatively characterized by means of a scanning microscopic light scattering. The reactions formed homogeneous network structure with about 0.5 nm of mesh in the gels. Mechanical properties of the obtained gels were investigated by compression test. Increasing of the crosslinking density with increasing of the monomer concentration, number of thiol group of the monomer or reaction conversion, raised Young's modulus, and breaking stress of the gels. Cogelation of the tri‐, tetra‐, of hexa‐thiol monomer and dithiol monomers yielded soft and flexible gels. Reduction of the disulfide bonds in the gels by dithiothreitol turned the gel into solution. Heating of the resulting solution induced the regelation by reforming of the disulfide bonds. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3749–3756

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Section: Introductionmentioning

confidence: 99%

Synthesis and properties of multifunctional thiol crosslinked gels containing disulfide bond in the network structure

Naga

Moriyama

Furukawa

2017

J. Polym. Sci. Part A: Polym. Chem.

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“…Neckers et al reported synthesis of Si containing unsaturated star polymers by hydrosilylation reaction of 1,3,5-triethynylbenzene (TEB) and (p-(dimethylsilyl)phenyl)acetylene (Wang, Kaafarani, & Neckers, 2003). Some organic-inorganic hybrid gels containing σ-π conjugated Si-vinylene units in the network were developed in our laboratory by the hydrosilylation reaction of TEB and 1,1,3,3-tetramethyldisiloxane or 1,4-bisdimetylsilylbenzene in toluene (Naga, Iwashita, Nagino, Miyanaga, & Furukawa, 2015). Although, the hydrosilylation reaction is one of the effective methods to synthesize the network structures containing Si-vinylene units, the multifunctional ethynylene compounds, such as TEB, should be necessary.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Network Polymers Containing Si-Vinylene Units by Mizoroki-Heck Reaction

Naga¹,

Sugano²,

Senda³

2017

IJC

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Network polymers containing Si-vinylene units have been synthesized by Mizoroki-Heck reaction of cyclic siloxane or cubic silsesquioxane compounds with vinyl groups, as joint molecules, and dibromo aryl compounds, as linker molecules, using a Pd catalyst. The reaction of 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane (TVMCTS) or octavinyloctasilsesquioxane (PVOSS) with o, m, p-dibromobenzene (DBB) or 4,4'-dibromobiphenyl (DBBP) yielded the corresponding network polymers, except TVMCTS-oDBB system. Optical properties of the network polymers were studied by UV-vis and photoluminescence spectroscopy, and absorption and emission derived from s-p conjugation of the Si-vinylene units were detected. Copolymerization of TVMCTS-DBB/bromobenzene yielded CHCl3 soluble fraction due to formation of the network fragments. The network polymers of TVMCTS or PVOSS with 2,7-dibromofluorene (BFl) or 9,9-dihexyl-2,7-dibromofluorene were synthesized by the same procedures. Scanning electron microscope image of TVMCTS-BFl network polymer indicated formation of porous structure. The network polymers have been also synthesized by the reactions of multifunctional aryl bromide, as the joint molecules, with divinyl or dially silane compounds, as the linker molecules. The molecular structure of the multifunctional aryl bromide affected the emission wavelengths of the network polymers. In the case of the 2,2’,7,7’-tetrabromo-9,9’-spirobifluorene-based network polymers, the emission spectra widely ranged from 450 to 500 nm, which were sensitive to molecular structure of the divinyl or dially silane compounds.

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Quaternary Ammonium Salts: Catalysts for Hydrosilylation of Alkynes with Hydrosilanes

et al. 2023

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Mixing i‐PrI and DABCO in solvent EtCN gave two quaternary ammonium salts (QASs) quantitatively, one of which is monocationic (QAS‐1) and the other is dicationic (QAS‐2). These QASs were found to catalyze hydrosilylation of alkynes with hydrosilanes (HAH) without the aid of metal and metalloid catalysts. This organocatalysis can be applied to a variety of alkynes: terminal/internal aryl and alkyl alkynes with/without a functional group. With dihydrosilanes (H2Si), the HAH occurred with high E‐selectivity through syn addition, which was exclusively observed when using terminal alkyl alkynes, irrespective of a hydrosilane used. A scalable HAH is also feasible. The H−Si unit remaining in alkenylsilanes derived from H2Si is available for dehydrogenative alkynylation and N‐heteroarylation under zinc–pyridine catalysis. This synthetic application delivers unique silicon compounds that have, for instance, alkyl, aryl, alkenyl, and alkynyl groups in a single molecule. Mechanistic studies suggested that alkynes activated by QASs irreversibly react with hydrosilanes that become more nucleophilic by the coordination of EtCN. A radical pathway is unlikely. The QAS catalysts can be recovered and reused at least 5 times.

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Synthesis and optical properties of σ–π conjugated organic–inorganic hybrid gels

Cited by 3 publications

References 21 publications

Synthesis and properties of multifunctional thiol crosslinked gels containing disulfide bond in the network structure

Synthesis and properties of multifunctional thiol crosslinked gels containing disulfide bond in the network structure

Synthesis of Network Polymers Containing Si-Vinylene Units by Mizoroki-Heck Reaction

Quaternary Ammonium Salts: Catalysts for Hydrosilylation of Alkynes with Hydrosilanes

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