Synthesis,Structure, Photoluminescence,and Electroluminescence of Siloles that Contain Planar Fluorescent Chromophores

Herein, a new series of siloles that were 2,5‐substituted with planar fluorescent chromophores (PFCs), including fluorene, fluoranthene, naphthalene, pyrene, and anthracene, were synthesized and characterized. These compounds showed weak emission in the solution state, owing to active intramolecular rotation (IMR), but the synergistic effect from electronic coupling between the PFC and the silole ring compensated for the emission quenching by the IMR process to some extent, thereby affording higher emission efficiencies than those of 2,3,4,5‐tetraphenylsiloles in solution. These new siloles showed enhanced emission efficiencies in the aggregated state. The electroluminescence (EL) color and efficiency of new siloles were sensitive towards the PFC. Siloles containing naphthalene moieties showed green EL emission, whilst those containing anthracene moieties showed orange EL emission. The siloles containing pyrene moieties exhibited yellow EL emission at 546 nm, with a peak luminance of 49000 cd cm^?2 and a high current efficiency of 9.1 cd A^?1.     

Colloidal aspects relating to direct incorporation of TiO2 nanoparticles into mesoporous spheres by an aerosol-assisted process

Titania nanoparticles have been incorporated into spherical mesoporous silica powders by an aerosol-assisted synthesis process from both aqueous and ethanol-based precursor dispersions. Transmission electron microscopy (TEM) showed that the titania nanoparticles exist as single particles or small aggregates within the mesoporous carrier particles and analysis of the nitrogen adsorption isotherms proved that the pore blocking of the particles is small. Particle size and zeta potential measurements showed that the addition of tetraethoxysiloxane (TEOS), and also hexadecyl trimethyl ammonium bromide (C16TAB) induced flocculation of the TiO2 nanoparticles. The higher yield and narrower size distribution of the composite powder produced from ethanol-based dispersions compared to the aqueous dispersions could be related to a smaller degree of aggregation, indicated by rheological measurements.     

Synthesis and characterization of 11-vertex platinaborane compounds having nido-PtB10H12 and nido-Pt2B9H10 skeletons

The reaction of closo-[B₁₀H₁₀]²⁻ with [PtCl₂(PPh₃)₂] in MeOH at reflux affords the B-methoxy substituted 11-vertex nido-platinaborane compound [(PPh₃)₂PtB₁₀H₁₀-8-H_0.5(OCH₃)_0.5-10-(OCH₃)] (1) and the known species [(PPh₃)₂PtB₁₀H₁₁-8-(OCH₃)] (2) and 1,6-(PPh₃)₂B₁₀H₈ (3). The same reaction under solvothermal condition gives the partially degraded diplatinaborane [(PPh₃)₂(μ-PPh₂)Pt₂B₉H₇-3,9,11-(OMe)₃] (4) with a novel nido-Pt₂B₉H₁₀ skeleton. The new metallaborane compounds have been characterized by spectroscopic methods and single-crystal X-ray analyses. In particular, computational/theoretical chemistry supports the ultimate structural confirmation of 4. The structures of these metallaboranes exhibit interesting intra- and/or intermolecular C-H?O hydrogen bonding interactions.     

From A Fluorescent Chromophore in Solution to An Efficient Emitter in the Solid State

Polycyclic aromatic hydrocarbons (PAHs) normally exhibit efficient fluorescence in dilute solutions, whereas their emission is significantly quenched in the aggregated state due to the formation of π‐aggregates/excimers. The rigid and planar structure of PAHs plays a positive role in terms of fluorescence in solution but a negative one in the aggregated state. To bestow PAHs a luminescent ability in the solid state, we constructed a non‐coplanar PAH‐substituted ethene. By using the planar PAH fluoranthene as a building block, a highly efficient solid‐state emitter with a fluorescence quantum efficiency of unity in the aggregated state was obtained. OLEDs with contain the molecule as an emitter reach a luminance up to 20 520 cd m^?2 and an efficiency of 10 cd A^?1.     

Synthesis, crystal structure, and optical properties of a three-dimensional quaternary Hg-In-S-Cl chalcohalide: Hg7InS6Cl5

A crystalline three-dimensional (3D) quaternary chalcohalide, Hg(7)InS(6)Cl(5) (1), has been synthesized through a solid-state reaction under medium temperature. It is the first example in the family of the Hg-IIIA-Q-X (Q = S, Se, Te; X = F, Cl, Br, I) systems. Compound 1 features a 3D network and has an optical band gap of 2.54 eV.     

Thermo-Kinetic Study of Piperazine Immobilized Silica Surface

In the present study, the degradation process of piperazine (PP) immobilized silica gel (SiPP) is investigated under dynamic conditions. The degradation of SiPP is studied with thermogravimetric analyzer (TGA). The kinetics of degradation process is analyzed by Kissinger method, Flynn–Wall–Ozawa's (FWO) method, and Deconvolution method. It is found that degradation of SiPP can be described by parallel independent two-portion process model, which includes two processing state of the system (marked by processes 1 and 2), where process 1 and 2 can be attributed to decomposition processes of organic moiety attached on silica surface. The apparent activation energy (E_a) is calculated by Flynn–Wall–Ozawa's (FWO) method and deconvolution method.