Preparation and properties of a POSS-containing organic-inorganic hybrid crosslinked polymer

A novel POSS-containing organic-inorganic hybrid crosslinked polymer was prepared by hydrosilylation reaction of octahydridosilsesquioxane （TsHs） with 4,4＇-bis（4-altyloxybenzoyloxy）phenyl （diene A）. Its structure and property was characterized by FFIR, 29Si NMR, TGA and ellipsometer, respectively. The results show that the hybrid polymer possesses high thermal stability and low dielectric constant of 1.97 at optical frequencies.

PREPARATION OF SOLUBLE SUBSTITUTED POLYACETYLENE OPTICAL LIMITING MATERIAL

Two novel polyacetylenes bearing nonlinear optical chromophoric group poly（3-（4-[4-（n-butyloxy） phenylazophenyl]carbonyl）oxy-1-propyne） （poly（1a）） and poly（3-（4-[4-（n-heptyloxy）phenylazophenyl]carbonyl）-oxy-l- propyne） （poly（lb）） were synthesized with [Rh（nbd）Cl]2-EtaN as catalysts. These polyacetylenes are soluble by using an alkyl spacer and an alkyloxyl group as a substituent. They were characterized by FTIR, NMR, GPC and UV-Vis and their optical limiting and nonlinear optical properties were investigated using 8 ns pulse at 532 nm wavenumber. The results show that these soluble functional polyacetylenes possess optical limiting properties and large nonlinear optical properties and poly（1b） possesses better optical limiting and nonlinear optical properties than poly（ 1 a）.

Sequence structure controllable polymerization-induced self-assembly

Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating biosynthesis.However,the reported PISA formulations primarily focus on developing nano-objects with new chemical compositions and rarely on structural regulation of polymers with specific components.Herein,sequence structure controllable polymerization-induced self-assembly(SCPISA)is reported by using 7-(2-methacryloyloxyethoxy)-4-methylcoumarin(CMA)as a monomer.During the copolymerization of 2-hydroxyethyl methacrylate(HEMA)and CMA,controlled incorporation of CMA units into the polymer chains can be realized by programmable light/heat changes.SCPISA-based P(HEMA-co-CMA)copolymers with the same composition but different sequence structures generate a range of assemblies.Moreover,the morphologies of the resultant nano-objects can also be controlled by regulating the feed molar ratio of CMA and HEMA,which is similar to the conventional PISA,but the synthesis procedure is obviously simplified in SCPISA.The versatility of the methodology is further demonstrated by the fabrication of different functional nano-objects with sequence structure-dependent morphologies in SCPISA systems with different functional monomers.

Synthesis and characterization of luminescent organic-inorganic hybrid nanocomposite from polyhedral oligomeric silsesquioxane

A novel polyhedral oligomeric silsesquioxane(POSS)-based organic-inorganic hybrid nanocomposite(EF-POSS) was prepared by Pt-catalyzed hydrosilylation reaction of octahydridosilsesquioxane(T_8H_8,POSS) with a luminescent substituted acetylene(2- ethynyl-7-(4-(4-methylstyryl)styryl)-9,9-dioctyl-9H-fluorene(EF)) in high yield.The hybrid nanocomposite was soluble in common solvents such as CH_2Cl_2,CHCl_3,THF and 1,4-dioxane.Its structure and property were characterized by FTIR, NMR,TGA,UV and PL,respectively.The results show that the hybrid nanocomposite with high thermal stability emits stable blue light as a result of photo excitation and possesses high photoluminescence quantum efficiency(φ_(FL)).

Synthesis and Crystal Structure of Novel Mixed-metal Alkoxide Clusters of Ytterbium and Sodium: Yb_4O_4(O^iPr)_(16)Na_(12)

The mixed-metal cluster Yb4O4（OiPr）16Na12 has been synthesized and structurally determined by IR, elemental analysis, and single-crystal X-ray diffraction. The crystal belongs to the cubic system, space group P23 with a = b = c = 13.9788（3）A, V = 2731.55（10）A3, Z = 1, Dc = 1.202 g/cm3, Mr = 1977.42,/J = 3.480 mm-1, F（000） = 972, the final R = 0.0288 and wR = 0.1511 for 1677 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that Yb4O4（Oipr）16Na12 is centrosym- metric and the structure contains four ytterbium metals and twelve sodium metals, and each ytterbium atom is coordinated by six oxygen atoms. In addition, an ancillary computational analysis of the optimized molecular unit was provided. The large energy gap （3,31 eV） between HOMO and LUMO indicates that the structure framework is particularly stable.

Heterogeneousα-Diimine Nickel Catalysts with Improved Catalytic Performance in Ethylene Polymerization

Heterogenization can improve the thermal tolerance of olefin polymerization catalysts and result in good product morphology con-trol,which are two important parameters for industrial polyethylene production.In this work,α-diimine nickel catalysts bearing-OH or-ONa anchoring groups were designed and prepared.The anchoring groups can enable facile heterogenization of the cata-lysts on silica.The heterogeneous catalysts demonstrated enhanced thermal stabilities,along with high catalytic activity at 120℃(up to 5.5×10^(6)g·PE·mol·Ni^(-1)·h^(-1)).Furthermore,the heterogenization process results in the improvements of many other parame-ters,including polymer morphology control,catalytic activity(up to 1.9×10^(7)g·PE·mol·Ni^(-1)·h^(-1))and polyethylene molecular weight(Mn up to 2.3×10^(6)g·mol^(-1)).More importantly,the structure and properties of the polymer products can be controlled by catalyst structures,polymerization conditions and heterogenization to achieve good mechanical properties and elasticity.

A“Catalyst+Support”Strategy for Salicylaldimine Nickel Catalyzed Ethylene Polymerization and Copolymerization with Polar Monomers

Polyolefins,as one of the most productive synthetic polymer materials,have been widely used in industry and daily life[1-2].However,due to their"non-polar"nature,polyolefins have poor compatibility and adhesion to polar materials,limiting their application in many fields[3-5].

Cooperative Dual Organocatalytic Asymmetric Decarboxylative[4+3]Annulations with Benzoxazinanones

The cooperative catalysis of an achiral Lewis base and a chiral N-heterocyclic carbene(NHC)enables a highly enantioselective[4+3]annulation of benzoxazinanones with isatin-derived enals.DMAP serves as a nucleophilic Lewis base to promote decarboxylation of benzoxazinanones,which leads to azaortho-xylylene intermediates that undergo[4+3]annulations with NHC-bound homoenolates.This method breaks the substrate scope limitation of transition-metal-catalyzed variants,thus a broader range of benzoxazinanones are tolerated,and provides a straightforward entry to enantioenriched spirooxindoles in high structural diversity.

Mineralization of HA crystals regulated by terephthaloyl chloride-modified silk fibroin films

Terephthaloyl 氯化物(DB ) 修改了丝绸丝心蛋白(SF ) 电影被沉浸进乘模仿的身体液体(1.5 SBF ) 的 1.5 调整 hydroxyapatite 的矿化作用(哈) 在大约 36.5 点的晶体 ? 吗？？