A nanostructured skeleton catalyst: Suzuki-coupling with a reusable and sustainable nanoporous metallic glass Pd-catalyst

Nanoporous metallic glass Pd, which was fabricated by dealloying of a glassy metallic alloy Pd(30)Ni(50)P(20), exhibited a remarkable catalytic activity for the Suzuki-coupling reaction between iodoarenes and arylboronic acids under mild conditions. Moreover, the catalyst can be reused several times without a significant loss of catalytic activity.     

Photodissociation of pyrene dimer radical cation during the pulse radiolysis–laser flash photolysis combined method

Photodissociation of pyrene (Py) dimer radical cation (Py ₂ ^?+ ) giving pyrene radical cation (Py^?+) and Py and subsequent regeneration of Py ₂ ^?+ by association of Py^?+ and Py were directly observed during the pulse radiolysis–laser flash photolysis combined method at room temperature. When Py ₂ ^?+ was excited at the local excitation band with the 532-nm laser flash, the rapid growth and decay of monomeric Py^?+ were observed at 460 nm. The dissociation of Py ₂ ^?+ proceeded via a one-photon process to give the ground-state Py^?+(D₀) and Py in the quantum yield (Φ_diss) of (2.9 ± 0.9) × 10^?3. It was shown that Py^?+ decayed with a time constant of several tens of nanoseconds, indicating that the association of Py^?+ with Py regenerating Py ₂ ^?+ proceeds at a diffusion-controlled rate. The photodissociation proceeded from the lowest excited state of Py ₂ ^?+ , even when Py ₂ ^?+ was excited to the higher excited state. The difference between the Φ_diss value of Py ₂ ^?+ and that previously reported for naphthalene dimer radical cation (Np ₂ ^?+ ) is discussed.     

一种新型氧氮杂大环化合物的光合成

以乙腈为溶剂,二苯甲酮为光敏化剂,6,6’-二甲基-4,4’-(三亚甲二氧基)-二-2-吡喃酮与N,N’-亚甲基双丙烯酰胺经光二重[2+2]环加成反应,位置选择性地合成了一种新型氧氮杂大环化合物,其结构经1H NMR,12C NMR,FT-IR和HR-MS表征。最佳光反应条件为:1 3.2 mmol,n(1)∶n(二苯甲酮)=1.0∶1.5,于300 W光照18 h,收率37%。     

Neuroprotective effects of edaravone-administration on 6-OHDA-treated dopaminergic neurons

Background

A recent human clinical trial of an Alzheimer's disease (AD) vaccine using amyloid beta (Aβ) 1–42 plus QS-21 adjuvant produced some positive results, but was halted due to meningoencephalitis in some participants. The development of a vaccine with mutant Aβ peptides that avoids the use of an adjuvant may result in an effective and safer human vaccine.

Results

All peptides tested showed high antibody responses, were long-lasting, and demonstrated good memory response. Epitope mapping indicated that peptide mutation did not lead to epitope switching. Mutant peptides induced different inflammation responses as evidenced by cytokine profiles. Ig isotyping indicated that adjuvant-free vaccination with peptides drove an adequate Th2 response. All anti-sera from vaccinated mice cross-reacted with human Aβ in APP/PS1 transgenic mouse brain tissue.

Conclusion

Our study demonstrated that an adjuvant-free vaccine with different Aβ peptides can be an effective and safe vaccination approach against AD. This study represents the first report of adjuvant-free vaccines utilizing Aβ peptides carrying diverse mutations in the T-cell epitope. These largely positive results provide encouragement for the future of the development of human vaccinations for AD.     

The simplest structure of a stable radical showing high fluorescence efficiency in solution: benzene donors with triarylmethyl radicals

Donor–radical acceptor systems have recently attracted much attention as efficient doublet emitters that offer significant advantages for applications such as OLEDs. We employed an alkylbenzene (mesityl group) as the simplest donor to date and added it to a diphenylpyridylmethyl radical acceptor. The (3,5-difluoro-4-pyridyl)bis[2,6-dichloro-4-(2,4,6-trimethylphenyl)phenyl]methyl radical (Mes₂F₂PyBTM) was prepared in only three steps from commercially available reagents. A stable radical composed of only one pyridine ring, four benzene rings, methyl groups, halogens, and hydrogens showed fluorescence of over 60% photoluminescence quantum yield (PLQY) in chloroform, dichloromethane, and PMMA. The key to high fluorescence efficiency was benzene rings perpendicular to the diphenylpyridylmethyl radical in the doublet ground (D₀) state. The relatively low energy of the β-HOMO and the electron-accepting character of the radical enabled the use of benzenes as electron donors. Furthermore, the structural relaxation of the doublet lowest excited (D₁) state was minimized by steric hindrance of the methyl groups. The reasons for this high efficiency include the relatively fast fluorescence transition and the slow internal conversion, both of which were explained by the overlap density between the D₁ and D₀ states.

By adding mesityl donors to a diphenylpyridyl radical acceptor, a highly luminescent stable radical was prepared in three steps from commercially available reagents. The photoluminescence quantum yield was as much as 69% in chloroform.