Controllable Si-C Bond Activation Enables Stereocontrol in the Palladium-Catalyzed [4+2] Annulation of Cyclopropenes with Benzosilacyclobutanes.

A novel and unusual palladium-catalyzed [4+2] annulation of cyclopropenes with benzosilacyclobutanes is reported. This reaction occurred through chemoselective Si-C(sp2 ) bond activation in synergy with ring expansion/insertion of cyclopropenes to form new C(sp2 )-C(sp3 ) and Si-C(sp3 ) bonds. An array of previously elusive bicyclic skeleton with high strain, silabicyclo[4.1.0]heptanes, were formed in good yields with excellent diastereoselectivity under mild conditions. An asymmetric version of the reaction with a chiral phosphoramidite ligand furnished a variety of chiral bicyclic silaheterocycle derivatives with good enantioselectivity (up to 95.5:4.5 er). Owing to the mild reaction conditions, the good stereoselectivity profile, and the ready availability of the functionalized precursors, this process constitutes a useful and straightforward strategy for the synthesis of densely functionalized silacycles.

[The Effect of Ambient Temperature on Human Head's Surface Skin Temperature].

It is important to understand heat loss from human head because human head produces much heat for its high metabolism, it also functions as a heat radiator to keep body heat balance. Heat loss from human head is closely related to its skin temperature. Therefore, skin surface temperature of human head changes with ambient temperature is studied. In this research, several positions were sampled and the advanced infrared detectors (the infrared thermal imager and the infrared thermometer) were used as tools for measurement. For the sake of comparison, the young volunteers were grouped into the boys team and the girls team. Results showed that, firstly, between the groups, there was only a little difference in that girls' head temperature was a little higher; secondly, head temperature of either girls or boys rises with air temperature till about 30 ℃; and thirdly, exercise has only a little effect on the head temperature variation. This research is practical for further investigation on head heat flow and referential for health diagnosing by comparing the data recorded in this experiment.

Chiral pinwheel clusters lacking local point chirality.

The supramolecular pinwheel cluster is a unique chiral structure with evident handedness. Previous studies reveal that the chiral pinwheels are composed of chiral or achiral molecules with polar groups, which result in strong intermolecular interactions such as hydrogen-bonding or dipole interactions. Herein, it is shown that the simple linear aromatic molecule, pentacene, can be self-assembled into large chiral pinwheel clusters on the semimetal Bi(111) surface, due to enhanced intermolecular interactions. The pentacene pinwheels reveal two levels of organizational chirality: the chiral hexamers resulting from asymmetric shifting along the long molecular axis, and chiral arrangement of six hexamers with a rotor motif. Furthermore, a new relation between the local point chirality and organizational chirality is identified from the pinwheels: the former is not essential for the latter in 2D pinwheel clusters of the pentacene molecule.

Common mechanism of Citrus Grandis Exocarpium in treatment of chronic obstructive pulmonary disease and lung cancer.

Objective: "Same treatment for different diseases" is a unique treatment strategy in traditional Chinese medicine. Two kinds of malignant respiratory diseases endanger human health-chronic obstructive pulmonary disease (COPD) and lung cancer. Citrus Grandis Exocarpium (Huajuhong in Chinese, HJH), a famous herbal, is always applied by Chinese medicine practitioners to dispersion the lung to resolve phlegm based on "syndrome differentiation and treatment" theory. However, the common mechanism for HJH's treatment of COPD and lung cancer is not clear. Methods: In this study, based on network pharmacology and molecular docking technology, the common mechanism of HJH in the treatment of COPD and lung cancer was studied. The active ingredients and related targets of HJH were integrated from TCMSP, BATMAN-TAM, STP, and Pubchem databases. The standard names of these targets were united by UniProt database. Targets of COPD and lung cancer were enriched through GeneCards, NCBI (Gene), Therapeutic Target Database, and DisGeNET (v7.0) databases. Then the intersection targets of HJH and diseases were obtained. The STRING network and the Cytoscape 3.7.2 were used to construct PPI network, the DAVID database was used to perform GO and KEGG analysis. Then Cytoscape 3.6.1 was used to build "ingredient-target-signal pathway" network. Finally, AutoDock 1.5.6 software was used to perform molecular docking of key proteins and molecules. Results: Eleven active ingredients in HJH were obtained by searching the database, corresponding to 184 HJH-COPD-lung cancer targets intersection. The results of biological network analysis showed that naringenin, the active component in HJH, could mainly act on target proteins such as AKT1, EGFR. Then through positive regulation of vasoconstriction and other biological processes, naringenin could regulate estrogen signaling pathway, VEGF signaling pathway, HIF-1 signaling pathway, ErbB signaling pathway, PI3K-Akt signaling pathway to play an important role in the treatment of both COPD and lung cancer. Conclusion: Network pharmacology was employed to systematically investigate the active ingredients and targets of HJH in treatment of COPD and lung cancer. And then, the common pharmacodynamic network of HJH for the two malignant respiratory diseases was firstly described. Furthermore, naringenin was proved to strongly bind with AKT1 and EGFR. It may provide the scientific basis for understanding the "Same treatment for different diseases" strategy in traditional Chinese medicine and inspirit subsequent drug discovery for COPD, lung cancer and other malignant lung diseases.

Stereo- and regio-selective synthesis of silicon-containing diborylalkenes via platinum-catalyzed mono-lateral diboration of dialkynylsilanes.

A highly chemoselective platinum-catalyzed mono-lateral diboration of dialkynylsilanes for the construction of silicon-tethered alkynyl diborylalkenes is described, in which tris(4-methoxyphenyl)phosphine was found to be an effective ligand for the cis-addition of diboron agents to the silicon-tethered alkynes, and the chiral ligand (AFSi-Phos)-mediated diboration of dialkynylsilanes resulted in the desymmetric construction of silicon-stereogenic centers with promising enantioselectivity.

Stereospecific Si-C coupling and remote control of axial chirality by enantioselective palladium-catalyzed hydrosilylation of maleimides.

Hydrosilylation of unsaturated carbon-carbon bonds with hydrosilanes is a very important process to access organosilicon compounds and ranks as one of the most fundamental reactions in organic chemistry. However, catalytic asymmetric hydrosilylation of activated alkenes and internal alkenes has proven elusive, due to competing reduction of carbon-carbon double bond or isomerization processes. Herein, we report a highly enantioselective Si-C coupling by hydrosilylation of carbonyl-activated alkenes using a palladium catalyst with a chiral TADDOL-derived phosphoramidite ligand, which inhibits O-hydrosilylation/olefin reduction. The stereospecific Si-C coupling/hydrosilylation of maleimides affords a series of silyl succinimides with up to 99% yield, >99:1 diastereoselectivity and >99:1 enantioselectivity. The high degree of stereoselectivity exerts remote control of axial chirality, leading to functionalized, axially chiral succinimides which are versatile building blocks. The product utility is highlighted by the enantioselective construction of N-heterocycles bearing up to three stereocenters.

Catalytic Asymmetric trans-Selective Hydrosilylation of Bisalkynes to Access AIE and CPL-Active Silicon-Stereogenic Benzosiloles.

Chirality widely exists in a diverse array of biologically active molecules and life forms, and the catalytic constructions of chiral molecules have triggered a heightened interest in the fields of chemistry and materials and pharmaceutical sciences. However, the synthesis of silicon-stereogenic organosilicon compounds is generally recognized as a much more difficult task than that of carbon-stereogenic centers because of no abundant organosilicon-based chiral sources in nature. Herein, we reported a highly enantioselective rhodium-catalyzed trans-selective hydrosilylation of silicon-tethered bisalkynes to access chiral benzosiloles bearing a silicon-stereogenic center. This protocol featured with chiral Ar-BINMOL-Phos bearing hydrogen-bond donors as a privileged P-ligand for catalytic asymmetric hydrosilylation that is operationally simple and has 100% atom-economy with good functional group tolerability as well as high enantioselectivity (up to >99:1 er). Benefiting from the trans-selective hydrosilylation with the aid of Rh/Ar-BINMOL-Phos-based asymmetric catalysis, the Si-stereogenic benzosiloles exhibited pronounced aggregation-induced emission (AIE) and circularly polarized luminescence (CPL) activity.

Shape-controlled ceria-reduced graphene oxide nanocomposites toward high-sensitive in situ detection of nitric oxide.

Nitric oxide (NO) is an important signal molecule released by most cancer cells under drug stimulation or/and disease development but it is extremely challenging to in situ while real-time sensitively detect NO due to its large diffusivity, low concentration and fast decay. Herein, shape-controlled reduced graphene oxide nanocomposing with ceria (rGO-CeO2) was synthesized via hydrothermal reaction to construct a highly sensitive real-time sensing platform for NO detection. The crystal shape of CeO2 nanoparticles in rGO-CeO2 composites significantly affects the sensing performance of rGO-CeO2, of which the regular hexagonal nanocrystal CeO2 achieves the highest sensitivity (1676.06 mA cm(-2) M(-1)), a wide dynamic range (18.0 nM to 5.6 µM) and a low detection limit (9.6 nM). This attributes to a synergical effect from high catalytic activity of the specifically shaped CeO2 nanocrystal and good conductivity/high surface area of rGO. This work demonstrates a way by rationally compose individual merit components while well control the nanostructure for a superior synergistic effect to build a smart sensing platform, while offering a great application potential to sensitively real-time detect NO released from living cells for diagnosis or/and studies of complicated biological processes.