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One of frequent uses of palladium as catalyst is in the Suzuki-Miyaura cross-coupling reaction, which is one of key reactions in the synthesis of pharmaceuticals, fine chemicals, and electronic device materials. In this work, we explored a unique circulation reactor system for Suzuki-Miyaura CC coupling reaction, in which a robust microflower self-assembled from bistheophyllines heptane (PdBTC7) and PdCl2 were packed in column. Injection of the reactants of bromobenzene and phenylboronic acid 51 times in definite interval in the eluent of water/NaCl/ethanol could give continuously biphenyl product, showing the performance of catalyst in 4498 of TON and 8996 h−1 of TOF.

Novel N-doped carbon nanonet flakes (NCNFs), consisting of three-dimensional interconnected carbon nanotube and penetrable mesopore channels were synthesized in the assistance of a hybrid catalytic template of silica-coated-linear polyethyleneimine (PEI). Resorcinol-formaldehyde resin and melamine were used as precursors for carbon and nitrogen, respectively, which were spontaneously formed on the silica-coated-PEI template and then annealed at 700 °C in a N2 atmosphere to be transformed into the hierarchical 3D N-doped carbon nanonetworks. The obtained NCNFs possess high surface area (946 m2 g−1), uniform pore size (2−5 nm), and excellent electron and ion conductivity, which were quite beneficial for electrochemical double-layered supercapacitors (EDLSs). The supercapacitor synthesized from NCNFs electrodes exhibited both extremely high capacitance (up to 613 F g−1 at 1 A g−1) and excellent long-term capacitance retention performance (96% capacitive retention after 20,000 cycles), which established the current processing among the most competitive strategies for the synthesis of high performance supercapacitors.

This paper describes a facile approach to a biomimetic rapid fabrication of ultrathin silica nanotubes with a highly uniform diameter of 10 nm and inner hollow of around 3 nm. The synthesis is carried out through a spontaneous polycondensation of alkoxysilane on polyamine crystalline fibrils that were conveniently produced from the neutralization of a solution of protonated linear polyethyleneimine (LPEI–H+) by alkali compounds. A simple mixing the fibrils with alkoxysilane in aqueous solution allowed for the rapid formation of silica to produce LPEI@silica hybrid nanotubes. These 10-nm nanotubes were hierarchically organized in a mat-like morphology with a typical size of 1–2 micrometers. The subsequent removal of organic LPEI via calcination resulted in silica nanotubes that keep this morphology. The morphology, the structure, the pore properties and the formation mechanism of the silica nanotubes were carefully investigated with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller measurements (BET), and X-ray diffraction (XRD). Detailed studies demonstrated that the formation of the nanotubes depends on the molar ratio of [OH]/[CH2CH2NH] during the neutralization as well as on the basicity of the alkali compound and on the concentration of the silica source. The synthesis of silica nanotubes established here could be easily applied to a fabrication on the kilogram scale. Silica nanotubes that were obtained from the calcination of hybrid nanotubes of LPEI@silica in an N2 atmosphere showed a distinct photoluminescence centered at 540 nm with a maximum excitation wavelength of 320 nm. Furthermore, LPEI@silica hybrid nanotubes were applied to create silica–carbon composite nanotubes by alternative adsorption of ionic polymers and subsequent carbonization.

We report the rational control of the nanostructure and surface morphology of a polyamine@silica nanoribbon-based hybrid nanograss film, which was generated by performing a biomimetic silica mineralization reaction on a nanostructured linear polyethyleneimine (LPEI) layer preorganized on the inner wall of a glass tube. We found that the film thickness, size and density of the nanoribbons and the aggregation/orientation of the nanoribbons in the film were facile to tune by simple adjustment of the biomimetic silicification conditions and LPEI self-assembly on the substrate. Our LPEI-mediated nanograss process allows the facile and programmable generation of a wide range of nanostructures and surface morphologies without the need for complex molecular design or tedious techniques. This ribbon-based nanograss has characteristics of a LPEI@silica hybrid structure, suggesting that LPEI, as a polymeric secondary amine, is available for subsequent chemical reaction. This feature was exploited to functionalize the nanograss film with three representative species, namely porphyrin, Au nanoparticles and titania. Of particular note, the novel silica@titania composite nanograss surface demonstrated the ability to convert its wetting behavior between the extreme states (superhydrophobic–superhydrophilic) by surface hydrophobic treatment and UV irradiation. The anatase titania component in the nanograss film acts as a highly efficient photocatalyst for the decomposition of the low-surface-energy organic components attached to the nanosurface. The ease with which the nanostructure can be controlled and facilely functionalized makes our nanograss potentially important for device-based application in microfluidic, microreactor and biomedical fields.

Systems that show circularly polarized luminescence (CPL) are usually constructed in one of two possible ways: either covalently binding the chiral moieties (usually organic compounds) to luminophores (inorganic or organic compounds) or associating the luminophores as guests with chiral hosts (usually organic compounds). Herein, we propose inorganicbased CPL-active systems constructed by the “chiral hostluminescent guest” strategy, in which silica acts as a chiral host to endow various luminescent guests with CPL. The chiral silica was modified by silane coupling with amino or phenyl groups to allow interaction with luminescent guests, and then used in combination with acidic achiral dyes, lead-halide type perovskites, and aggregation-induced emission luminogens (AIEgens). Interestingly, when these achiral guests were noncovalently confined in surface-modified chiral silica, the guests showed chiroptical behavior in the circular dichroism (CD) spectra, and thus became CPL active, even though they are not inherently chiral. The surface functional groups on the silica play very important roles in transferring the chiral information from the silica to the guests. This work provides a new concept for constructing CPL-active systems using inorganic materials as a chiral source. [ABSTRACT FROM AUTHOR]

Two types of double-hydrophilic comb-coil block copolymers, (PVBC-g-PMOZ)-b-PNIPAM and (PVBC-g-PEI)-b-PNIPAM, possessing combs of poly(methyloxazoline) (PMOZ)/crystalline poly(ethyleneimine) (PEI) and coils of thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) were synthesized by a combination of RAFT block copolymerization of 4-chloromethyl styrene and N-isopropylacrylamide (NIPAM), ring-opening polymerization of 2-methyloxazoline, and the selective hydrolysis of PMOZ. These polymers showed remarkable thermo-responsiveness to give thermo-induced aggregates with different morphologies. [ABSTRACT FROM AUTHOR]

Poly(N-cyanoethylethyleneimine) (PCEI) obtained by Michael addition of linear poly(ethyleneimine) (LPEI) with acrylonitrile provided novel nanocrystalline entities which could serve as catalytic templates affording nanosheet-based structured silica under mild conditions. [ABSTRACT FROM AUTHOR]

Efficacious white OLED devices have been developed for lighting applications. The high efficacy was achieved by incorporating two key technologies: a 3-unit tandem hybrid device architecture and a random scattering light extraction enhancement structure. The light extraction enhancement structure was used for both external (EES) and internal (IES) applications. Laboratory results showed an EES device with 73.6 lm/W efficacy and an IES device with 111.7 lm/W efficacy. The 3-unit tandem structure and EES were also applied to production line devices and achieved over 80 lm/W efficacy at 1000 cd/m2 and over 60 lm/W at 3000 cd/m2. [ABSTRACT FROM AUTHOR]

Crystalline linear polyethyleneimine (LPEI) is a fascinating polymer that can be used as a catalyst, template and scaffold in order to direct the formation of silica with controllable compositions and spatial structures under mild conditions. Considering the crystallization and assembly of LPEI is temperature-dependent, we adopted different accelerated cooling processes of a hot aqueous solution of LPEI in order to modulate the LPEI crystalline aggregates. We then used them in the hydrolytic condensation of alkoxysilane. A series of silica with nanofibrils, nanotubes and nanowire-based structures were achieved simply by the LPEI aggregates which were pre-formed in defined cooling processes. These specific one-dimensional nanoscale structures assembled into microscale fibers-, sheet- and platelet-like coalescences. Furthermore, the deposition kinetics was also researched by the combination of other characterizations (e.g., pH measurement, 29Si MAS NMR). As a preliminary application, the hybrids of LPEI@SiO2 were used not only as an agent for reducing PtCl4 2- into Pt but also as host for loading Pt nanoparticles. The Pt-loaded silica showed good catalytic properties in the reduction of Rhodamine B by dimethylaminoborane (DMAB) [ABSTRACT FROM AUTHOR]

We report our new achievement on the direct generation of linear polyethylenimine@silica hybrid and silica thin films on various substrates, which is composed of 10 nm nanowire silica structure with tunable micro/nano hierarchical surface morphology. We found that a process for the rapid and controlled self-assembly of crystalline template layer of linear polyethylenimine on substrate surface is critical for the formation of ultrathin silica nanowire structure and micro/nano hierarchical morphology, since the template linear polyethylenimine layer directly promotes the hydrolytic condensation of alkoxysilanes. Templated silica mineralization on the self-assembled linear polyethylenimine layer was confirmed by the studies of X-ray photoelectron spectroscopy (XPS) and thin film X-ray diffraction (XRD). The surface of silica nanostructure and hierarchy could be well controlled by simply adjusting the conditions for LPEI assembly, such as the polymer concentrations and substrate surface property. After a simple fluorocarbon modification, the hierarchical silica nanowire thin film demonstrated robust and reliable super-repelling property toward a series of aqueous liquids (such as commercial inkjet (IJ) ink, soy source, milk). Comparative studies clearly confirmed the critical importance of surface hierarchy for enhancing super-repelling property. Moreover, we found that the forcibly formed dirty sports (both wet and dry) from the complexly composed liquids on the super-antiwetting surface could be easily and completely cleaned by simple water drop flow. We expect these tailored nanosurfaces would have the potentials for practical technological applications, such as liquid transferring, self-cleaning, microfluid, and biomedical-related devices. [ABSTRACT FROM AUTHOR]

The formation of silica films on the glass plate whose surface was precoated by crystalline linear poly(ethylenimine) (LPEI) in advance was systematically investigated via controlling the surface-specific crystallization of the LPEI on the glass plate. Immersing glass substrates into a hot aqueous solution of LPEI containing additives such as transition metal ions and acidic compounds and retaining them on 30 °C for desired periods resulted in the formation of crystalline LPEI layers on the substrates. Subsequently dipping this LPEI-coated glass into silica source solutions afforded successfully hierarchically structured silica film which coated continuously the surface of the substrates. In this two-step process, we found that the formation of hierarchically structured silica films strongly depended on the LPEI layer formed from the LPEI aqueous solutions containing different additives. The LPEI layer formed by changing the kinds of additives and their concentrations provides the differently structured silica films composed of turbine-like structures flatly lying-on and/or vertically standing-on as well as ribbon network structures on the surface of the substrates. Moreover, we functionalized these silica films by the introduction of hydrophobic alkyl chains or emissive Eu(III) complexes and investigated their wettability and emission properties. [ABSTRACT FROM AUTHOR]

The formation of hierarchical aggregates from linear polyethyleneimine (LPEI) was performed in aqueous media containing a series of divalent metal ions (MnII, FeII, CoII, NiII, CuII, ZnII) and their organization processes are investigated by transcribing the structure into hard silica frames which can be appropriately characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) measurements. Coexisting metal salts interact with LPEI viacoordination bonds between metal ions and amine groups in ethyleneimine (EI) units to form water-soluble complexes. Without suitable complexation, LPEI crystallizes without restriction and forms non-well controlled hierarchical microstructures even in the presence of metal ions. The molar ratios of EI units and metal ions strongly affect the morphologies of crystalline precipitates. Low values of the ratios lead to intricate flower-like structures composed of leaf-like fibers assembled in a random fashion. On the other hand, an increase of the ratios makes the structures well-shaped and flattened for constructing 2-D turbine-like morphology. These structures consist of numerous sheet structures grown in a radial fashion. XRD and XRF measurements reveal that these resulting solids are mainly composed of hydrated LPEI and imply that coordinating metal ions are located in the peripherals of LPEI microstructures. Finally, temporal morphological evolution experiments indicate that a metal ion which can coordinate with EI units serves as a regulator in the crystallization of LPEI and abundant crystal growth can proceed. [ABSTRACT FROM AUTHOR]

Silica deposition by mediation of aggregated linear poly(ethyleneimine) (LPEI) from a basic aqueous solution of sodium silicate can produce ordered silica with fibrous bundle structure hybridized with LPEI via zero-emission of organic by-products. By changing the polymer concentration and pH value of the aqueous solution of sodium silicate, we were able to control the architecture of the resulting silica. This process is environmentally benign and inexpensive and thus would be feasible for industrial scale-up for the fabrication of silica nanomaterials. In addition, a typical fibrous silica bundle was characterized by fluorescence X-ray analysis, solid state 29Si (CP/MAS) NMR, TG/DTA, thermo-calcination, N2/He adsorption–desorption experiments, and high resolution TEM. Interestingly, the fibrous silica bundle, which contains about 25% LPEI, served as an effective nanoreactor to reduce metal ions into nearly cluster-size metallic nanoparticles inside the silica. [ABSTRACT FROM AUTHOR]

Fabrication of monodisperse silica spheres with bright emission features is still valuable in challenging since the spheres are widely applicable in the fields of catalysis, imaging material, bio-encapsulation, drug delivery, coatings, cosmetic, energy storage, and so on. In this paper, we demonstrated a new one-pot approach to uniformed silica spheres via mediation of linear poly(ethyleneimine)s (PEIs) and acidic dyes. PEIs with different architectures possessing only secondary amine in backbone were used as mediators for silica deposition from hydrolytic condensation of tetramethoxysilane (TMOS). Under the optimized medium composition of methanol/water with 70/30 in volume, the PEts facilely promoted the hydrolytic condensation of TMOS to give rapidly and exclusively uniformed silica spheres. In this process, acidic dyes such as tetrakis(4-sulfonylphenyl)porphyrin (TSPP), tetrakis(4-carboxylphenyl)porphyrin (TCPP) can be incorporated with basic PEIs and play important role to produce relatively larger uniformed silica spheres entrapping the dyes inside. The diameters of the uniformed silica spheres ranged from 50 to 700nm depending upon polymer architectures. From time-course investigation, it is confirmed that the formation of the silica spheres has three stages: 1) early formation of widely distributed smaller spheres; 2) growth to uniformed intermediate silica spheres and 3) further growth into larger spheres with narrow distribution. [ABSTRACT FROM AUTHOR]

A unique hierarchically structured silica directed by simple hydrolytic condensation of tetramethoxysilane (TMOS) on aggregates of linear poly(ethylenemine) (LPEI) incorporated with acidic and basic additives was described. Interestingly, the shapes of the resulting silicas showed nanofiber-based plate, bundle, sphere, flower and stick upon the additives, such as HCl, ammonia, Tetra(4-sulfophenyl)porphyrin (TSPP), bifunctional organic acids. All the additives are relations in the proton transfer with LPEI in aqueous media thus induce the corresponding aggregates of the LPEI. Silicification just occurs on the aggregates to give the structured silica. [ABSTRACT FROM AUTHOR]

Ionic iron complex [(Me3tacn)2Fe2Cl3]+[(Me3tacn)FeCl3]−(1), which is readily soluble in methanol, acted as a powerful catalyst in controlled radical polymerization of styrene and MMA, and showed promising features of removal from the resulting polymers and was reusable after recovery from the crude products. [ABSTRACT FROM AUTHOR]