Assembly of Luminescent Chiral Gold(I)-Sulfido Clusters via Chiral Self-Sorting

Due to the ubiquity of chirality in nature, chiral self-assembly involving self-sorting behaviors has remained as one of the most important research topics of interests. Herein, starting from a racemic mixture of SEG-based (SEG=SEGPHOS) chlorogold(I) precursors, a unique chiral butterfly-shape hexadecanuclear gold(I) cluster (Au₁₆) with different ratios of R^SEG and S^SEG ligands is obtained via homoleptic and heterochiral self-sorting. More interestingly, by employing different chlorogold(I) precursors of opposite chirality (such as R ^SEG -Au₂ and S ^BIN -Au₂ (BIN=BINAP)), an unprecedented heteroleptic and heterochiral self-sorting strategy has been developed to give a series of heteroleptic chiral decanuclear gold(I) clusters (Au₁₀) with propellor-shape structures. Heterochiral and heteroleptic self-sorting have also been observed between enantiomers of homoleptic chiral Au₁₀ clusters to result in the heteroleptic chiral Au₁₀ clusters via cluster-to-cluster transformation. Incorporation of heteroleptic ligands is found to decrease the symmetry from S₄ of homoleptic meso Au₁₀ to C₂ of heteroleptic chiral Au₁₀ clusters. The chirality has been transferred from the axial chiral ligands and stored in the heteroleptic gold(I) clusters.     

Hepatoprotective Effect of Millettia dielsiana: In Vitro and In Silico Study

In silico docking studies of 50 selected compounds from Millettia dielsiana Harms ex Diels (family Leguminosae) were docked into the binding pocket of the PI3K/mTOR protein. In there, compounds trans−3−O-p-hydroxycinnamoyl ursolic acid (1) and 5,7,4′−trihydroxyisoflavone 7−O−β−D−apiofuranosyl−(1→6)−β−D−glucopyranoside (2) are predicted to be very promising inhibitors against PI3K/mTOR. They direct their cytotoxic activity against Hepatocellular carcinoma with binding affinity (BA) values, the pulling work spent to the co-crystallized ligand from the binding site of PI3K/mTOR (W and F_max), and the non-equilibrium binding free energy (∆G_neq^Jar) as BA values = −9.237 and −9.083 kcal/mol, W = 83.5 ± 10.6 kcal/mol with F_max = 336.2 ± 45.3 pN and 126.6 ± 21.7 kcal/mol with F_max = 430.3 ± 84.0 pN, and ∆G_neq^Jar = −69.86074 and −101.2317 kcal/mol, respectively. In molecular dynamic simulation, the RMSD value of the PI3K/mTOR complex with compounds (1 and 2) was in the range of 0.3 nm to the end of the simulation. Therefore, the compounds (1 and 2) are predicted to be very promising inhibitors against PI3K/mTOR. The crude extract, ethyl acetate fraction and compounds (1 and 2) from Millettia dielsiana exhibited moderate to potent in vitro cytotoxicity on Hepatocellular carcinoma cell line with IC₅₀ values of 81.2 µg/mL, 60.4 µg/mL, 23.1 μM, and 16.3 μM, respectively, and showed relatively potent to potent in vitro antioxidant activity on mouse hepatocytes with ED₅₀ values of 24.4 µg/mL, 19.3 µg/mL, 30.7 μM, and 20.5 μM, respectively. In conclusion, Millettia dielsiana and compounds (1 and 2) are predicted to have very promising cytotoxic activity against Hepatocellular carcinoma and have a hepatoprotective effect.     

核磁共振技术(NMR)在组合化学中的应用

对科学产生最大影响的分析方法是核磁共振技术(NMR),它被广泛用于许多领域.本文结合作者的研究结果评述了NMR在组合化学中的应用,着重于NMR在固相合成的应用、液态NMR和NMR在高通量筛选中的应用.     

2,2-Difluoro-3-hydroxyesters by reformatskii reaction

Ethyl bromodifluoroacetate undergoes facile Reformatskii addition to aldehydes and ketones to form 2,2-difluoro-3-hydroxyesters.     

Liquid crystal properties of a mesogenic polyacetylene, poly(11-[(4'-heptoxy-4-biphenylyl)carbonyloxy]-1-undecyne)

The liquid crystalline properties of a mesogenic poly(1-alkyne) and the corresponding monomer were studied using transmission electron microscopy, X-ray diffraction, polarizing optical microscopy and differential scanning calorimetry. The monomer exhibits a monotropic smectic A phase and a metastable crystalline phase. The rigid polymer backbones do not prevent the mesogenic moieties from packing into smectic A and B phases in the temperature ranges 127.6-74.1°C and 74.1°C-room temperature, respectively, on cooling from the isotropic melt.     

Anisotropy inc-axis oriented YBa2Cu3O7−δ

Muon spin relaxation (μSR) data taken at LAMPF on ac-axis oriented fine powder sample of YBa₂Cu₃O_7−δ (YBCO) embedded in epoxy are analyzed for relaxation rate anisotropy. Clear differences beyond simple magnetic field penetration depth anisotropy are observed forB‖c andB c. The low-temperature anisotropy ratio is consistent with oriented ceramic data. Small crystallite size and anisotropic flux pinning characteristics are suggested as the fundamental cause of the additional effects.     

Intramolecular 2+2 addition of a difluorovinyl ether aldehyde yields [3.2.0] And no [3.1.1] products

Irradiation of the difluorovinyl ether aldehyde 6 yields the tricyclic products 7 and 8 and the bicyclic dioxepene 9. There was no evidence for the formation of the isomeric [3.1.1] structure 1 containing the ring system of thromboxane A₂.     

Implications of a 17 keV neutrino for baryogenesis

There is some experimental evidence for a 17 keV component of the electron neutrino, in the form of the recent observations of kinks in the beta-decay spectra of tritium, ¹⁴C, ³⁵S and ⁶³Ni. In this paper I show that most particle-physics models consistent with the 17 keV neutrino require a baryogenesis scale below 10⁶ GeV. Furthermore, models with a 17 keV neutrino typically contain new sources of CP violation, and the cosmological baryon asymmetry could be generated by anomalous electroweak interactions during a first-order weak phase transition.