Blue-light-emitting multifunctional triphenylamine-centered starburst quinolines: synthesis, electrochemical and photophysical properties

A series of triphenylamine-centered starburst quinolines (1a-1g) have been synthesized by Friedl?nder condensation of the 4,4',4'-triacetyltriphenylamine (2) and 2-aminophenyl ketones (3a-3g) in the presence of catalytic sulfuric acid and characterized well. They are thermally robust with high glass transition temperatures (above 176.4 °C) and decomposition temperatures (above 406 °C). These compounds emit blue fluorescence with λ(max)(Em) ranging from 433 to 446 nm in dilute toluene solution and 461 to 502 nm in the solid-state and have a relatively high efficiency (Φ(u) = 0.98-0.57). 1a-1g have estimated ionization potentials (IP) of 4.54 to 6.45 eV which are significantly near or higher than those of well-known electron transport materials (ETMs), including tris(8-hydroxyquinoline)aluminium (Alq(3)) (IP = 5.7-5.9 eV), and previously reported oligoquinolines (IP = 5.53-5.81 eV). Quantum chemical calculations using DFT B3LYP/6-31G* showed the highest occupied molecular orbital (HOMO) of -5.05 to -4.81 eV, which is close to the work function of indium tin oxide (ITO). These results demonstrate the potential of 1a-1g as hole-transporting/light-emitting/electron-transport materials and the host-materials of a dopant for hole-injecting for applications in organic light-emitting devices.     

Photochemically inactivated hepatitis B virus promotes upregulation of Th1-type cytokines

Photochemical virus inactivation technology is widely used to improve the safety of blood products. However, the process by which this inactivation occurs and the resulting immunogenicity of treated viruses remain to be elucidated. This study aimed to explore the effects of two photochemical inactivation methods (methylene and riboflavin, MP and RP) on hepatitis B virus (HBV) immunogenicity. Inactivated HBV were incubated with PBMC from six healthy donors. Culture supernatants were collected at 0, 24 and 72 h for the analysis of HBsAg and HBeAg expression using ELISA. Cytokine expression was analyzed at 72 h using ELISA. Costimulatory and cell adhesion molecule mRNA expression was analyzed at 24 h by RT–PCR. No significant changes in HBsAg and HBeAg were detected following MP. However, the secretion of TNF‐α and IFN‐γ was upregulated. Expression of CD80, CD86, ICAM2 and LFA3 mRNA was also upregulated. In contrast, although RP did not significantly alter HBsAg expression, a reduction in HBeAg expression was observed. Furthermore, no upregulation of cytokines and intracellular molecule expression was observed following RP. These data indicate that the immunogenicity of HBV is retained following MP, and the inactivation of HBV could upregulate the Th1‐type cellular immune responses, which may play significant roles in the antiviral process.     

Intrinsic energy landscapes of amino acid side-chains

Amino acid side-chain conformational properties influence the overall structural and dynamic properties of proteins and, therefore, their biological functions. In this study, quantum mechanical (QM) potential energy surfaces for the rotation of side-chain χ(1) and χ(2) torsions in dipeptides in the alphaR, beta, and alphaL backbone conformations were calculated. The QM energy surfaces provide a broad view of the intrinsic conformational properties of each amino acid side-chain. The extent to which intrinsic energetics dictates side-chain orientation was studied through comparisons of the QM energy surfaces with χ(1) and χ(2) free energy surfaces from probability distributions obtained from a survey of high resolution crystal structures. In general, the survey probability maxima are centered in minima of the QM surfaces as expected for sp(3) (or sp(2) for χ(2) of Asn, Phe, Trp, and Tyr) atom centers with strong variations between amino acids occurring in the energies of the minima indicating intrinsic differences in rotamer preferences. High correlations between the QM and survey data were found for hydrophobic side-chains except Met, suggesting minimal influence of the protein and solution environments on their conformational distributions. Conversely, low correlations for polar or charged side-chains indicate a dominant role of the environment in stabilizing conformations that are not intrinsically favored. Data also link the presence of off-rotamers in His and Trp to favorable interactions with the backbone. Results also suggest that the intrinsic energetics of the side-chains of Phe and Tyr may play important roles in protein folding and stability. Analyses on whether intrinsic side-chain energetics can influence backbone preference identified a strong correlation for residues in the alphaL backbone conformation. It is suggested that this correlation reflects the intrinsic instability of the alphaL backbone such that assumption of this backbone conformation is facilitated by intrinsically favorable side-chain conformations. Together our results offer a broad overview of the conformational properties of amino acid side-chains and the QM data may be used as target data for force field optimization.     

In situ synthesis of nickel tiara-like clusters with two different thiolate bridges

Four nickel clusters, cyclo-[{Ni(μ-S(i)Pr)(μ-SMe)}(6)] (1), cyclo-[{Ni(μ-StBu)(μ-SMe)}(6)] (2), cyclo-[{Ni(μ-S(i)Pr)(μ-SEt)}(6)] (3) and cyclo-[{Ni(μ-StBu)(μ-SEt)}(10)] (4), based on thiolate ligands have been successfully synthesized and characterized by elemental analysis, FT-IR spectra, UV-vis-NIR spectra, powder X-ray diffraction and single-crystal X-ray diffraction. Intriguingly, the SMe and SEt ligands are generated from solvothermal in situ ligand synthesis through the cleavage of the S-S bond respectively. The four nickel thiolate clusters exhibit tiara-like frameworks consisting of two different types of thiolate ligands.     

Chemoselective synthesis of highly substituted 1,2-allenyl ketones, furans, and 2-alkynyl ketones from reaction of lithium selenolates with 1-(1-alkynyl)cyclopropyl ketones and electrophiles

A homo-Michael addition reaction of lithium selenolates with 1-(1-alkynyl)cyclopropyl ketones and the subsequent reaction with electrophiles such as PhSeBr, NFSI and NCS is reported. Based on the nature of electrophiles, this reaction may afford highly substituted 1,2-allenyl ketones or furans (E(+) = PhSe(+)) and 2-alkynyl ketones (E(+) = F(+), Cl(+), active halides) as the final products, respectively.     

Quantitative analysis of structure and bandgap changes in graphene oxide nanoribbons during thermal annealing

Graphene oxide nanoribbons (GONRs) are wide bandgap semiconductors that can be reduced to metallic graphene nanoribbons. The transformation of GONRs from their semiconductive to the metallic state by annealing has attracted significant interest due to its simplicity. However, the detailed process by which GONRs transform from wide-bandgap semiconductors to semimetals with a near zero bandgap is unclear. As a result, precise control of the bandgap between these two states is not currently achievable. Here, we quantitatively examine the removal of oxygen-containing groups and changes in the bandgap during thermal annealing of GONRs. X-ray photoelectron spectroscopy measurements show the progressive removal of oxygen-containing functional groups. Aberration-corrected scanning transmission electron microscopy reveals that initially small graphene regions in GONRs become large stacked graphitic layers during thermal annealing. These structural and chemical changes are correlated with progressive changes in the electrochemical bandgap, monitored by cyclic voltammetry. These results show that small changes in the thermal annealing temperature result in significant changes to the bandgap and chemical composition of GONRs and provide a straightforward method for tuning the bandgap in oxidized graphene structures.     

Cyanex301的纯化及其特性

研究了用Ｃｙａｎｅｘ３０１［ＴＭ］铵盐在苯中重结晶以纯化Ｃｙａｎｅｘ３０１的方法，该法收率６２．４％，产品纯度＞９９％。测定了经纯化后产品的红外光谱，研究了纯化产品在－水正庚烷体系中的分配平衡及其在正庚烷中的缔合，浓度在０．２～１．０ｍｏ１／Ｌ范围，Ｃｙａｎｅｘ３０１主要以二聚形式存在。     

Large-scale synthesis of tube-like ZnS and cable-like ZnS-ZnO arrays: Preparation through the sulfuration conversion from ZnO arrays via a simple chemical solution route

Arrayed structures are desirable for many applications, but the fabrication of many material arrays remains a significant challenge. As a prominent II-VI semiconductor, large-scale arrayed ZnS structure has not been easily fabricated. Here, we introduce a simple structure conversion route for the synthesis of novel arrayed structures, and large-scale tube-like ZnS structure arrays and cable-like ZnS-ZnO composite arrays were successfully prepared through sulfuration conversion from arrayed rod-like ZnO structure based on a hydrothermal method at low temperature. XRD, EDS, SEM, TEM and PL are used to confirm the formation of the novel arrayed structure and trace the conversion process. The results show that the conversion ratio can be conveniently tailored by the reaction time, and the PL properties of the obtained materials can be adjusted through the conversion ratio. Especially, the cable-like structure holds the PL properties of both ZnO and ZnS structures. This simple solution method can be further extended to the preparation of other semiconductor sulfide and selenide, and can amplify the application field of large-scale arrays of semiconductors.     

Synthesis and structural identification of a highly ordered mesoporous organosilica with large cagelike pores

Using 1,2-bis(trimethoxysilyl)ethane as organosiloxane precursor and a triblock copolymer surfactant, Pluronic F127, as template, a highly ordered mesoporous organosilica with large cagelike pores has been successfully synthesized. Its structure was resolved to be 3-D cubic Fmm by high-resolution transmission electron microscopy. The intergrowth of hexagonal close-packed and cubic close-packed phases was observed in this material. The effect of different siliceous precursors on the mesostructure was also investigated.