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Aryloxysulfonyl azides can be effectively activated by commercially available cobalt(II) complex of meso-tetraphenylporphyrin ([Co(TPP)]) at room temperature under neutral and nonoxidative conditions for selective radical aziridination of alkenes via metalloradical catalysis. The [Co(TPP)]-catalyzed radical aziridination system is suitable for different combinations of olefin substrates and aryloxysulfonyl azides, producing various N-aryloxysulfonyl aziridine derivatives in good to excellent yields. In addition to generating the environmentally benign N2 as the only byproduct, this Co(II)-based metalloradical aziridination process features mild reaction conditions and operational simplicity.

Co(II)-based metalloradical catalysis has, for the first time, been successfully applied for asymmetric intramolecular C–H alkylation of acceptor/acceptor-substituted diazo reagents. Through the design and synthesis of a new D2-symmetric chiral amidoporphyrin as the supporting ligand, the Co(II)-based metalloradical system, which operates at room temperature, is capable of 1,5-C–H alkylation of α-methoxycarbonyl-α-diazosulfones with a broad range of electronic properties, providing the 5-membered sulfolane derivatives in high yields with excellent diastereoselectivities and enantioselectivities. In addition to complete chemoselectivity toward allylic and allenic C–H bonds, the Co(II)-based metalloradical catalysis for asymmetric C–H alkylation features a remarkable degree of functional group tolerance.

The Co(II) complex of the D2h-symmetric amidoporphyrin 3,5-DitBu-IbuPhyrin, [Co(P1)], has proven to be an effective metalloradical catalyst for intermolecular amination of C(sp2)–H bonds of aldehydes with fluoroaryl azides. The [Co(P1)]-catalyzed process can employ aldehydes as the limiting reagents and operate under neutral and non-oxidative conditions, generating nitrogen gas as the only byproduct. The metalloradical aldehydic C–H amination is suitable for different combinations of aldehydes and fluoroaryl azides, producing the corresponding N-fluoroaryl amides in good to excellent yields. A series of mechanistic studies support a stepwise radical mechanism for the Co(II)-catalyzed intermolecular C–H amination.

This study aimed to assess the combined therapeutic efficacies with gene therapy and stem cell treatment and herb on the differentiation of hBMSCs into vascular endothelial cells under hypoxia condition. The third passage of hBMSCs were randomly divided into four groups, including control group (hBMSCs transfected with empty vectors), VEGF group (VEGF gene transfected to hBMSCs), AST group (cultured with AST), and VEGF + AST group (the intervention of VEGF group plus AST group). Each group was cultured at 37°C and 5% O2 for 2 weeks. Cell morphology was observed by inverted phase and were crowded and arranged irregularly in the control group and AST group, showing a fiber-like growth, while those in the VEGF group and VEGF plus AST group were mostly triangular or polygonal, exhibiting a colony-like growth, contrast microscope. CD31 was negative in the control group and AST group, while CD105 was positive in both groups, tested by flow cytometry assay. The positive rate of CD31 was significantly higher in the VEGF group than it in the VEGP + AST, and the positive rate of CD105 was lower in the VEGF group than it in the VEGF + AST group. The levels of VEGF and endothelial nitric oxide synthase (eNOS) by ELISA and the expression of endothelin and prostacyclin by west blot (WB) and RT-PCR were significantly higher in VEGF group and AST group and VEGF plus AST group, compared with control group. Further, the expression of endothelin and vWF and VEGFR-2 was highest in the VEGP + AST group and the expression of prostacyclin was lowest in VEGF group. AST can promote the secretion of VEGF from the differentiation of hBMSCs induced by VEGF gene transfected to hBMSCs by HIF-1α under hypoxia.

When a phospholipid monolayer containing a zinc-coordinated porphyrin species formed atop a self-assembled monolayer of heptadecafluoro-1-decanethiol (CF3(CF2)7(CH2)2SH) is subjected to photoelectrochemical current generation, a significant modulation effect is observed. Compared with devices that contain similar photoactive lipid monolayers but formed on 1-dodecanethiol SAMs, these fluorinated hybrid bilayers produce a >60% increase in cathodic currents and a similar decrease in anodic currents. Photovoltages recorded from these hybrid bilayers are found to vary in the same fashion. The modulation of photovoltaic responses in these hybrid-bilayer-based devices is explained by the opposite surface dipoles associated with the thiols employed in this study, which in one case (fluorothiol) increase and in another (alkanethiol) decrease the work function of the underlying gold substrates. A similar trend of photovoltage/photocurrent modulation is also observed if fullerene is used as the photoagent in these devices. Our results reveal the intricacy of orientated surface dipole in influencing the photovoltaic processes, and its subtle interplay with other factors related to the photoagents, such as their location and orientation within the organic matrix.

Catalytic aziridination of alkenes with nitrene sources via “C2+N1” addition represents a general approach for the direct synthesis of aziridines, the smallest three-membered N-heterocycles.[1] The enantioselective version of this catalytic process allows for efficient access to chiral nonracemic aziridines, which are versatile synthetic intermediates in asymmetric synthesis.[1-2] Several classes of transition metal-based chiral catalysts, such as Mn, Fe, Cu, Rh and Co complexes, have been found effective in catalyzing asymmetric olefin aziridination with different nitrene sources.[1,3] Besides iminoiodanes and haloamines, organic azides have been actively pursued as alternative nitrene sources for metal-catalyzed aziridination as they enjoy several advantages.[3] While sulfonyl and phosphoryl azides have been effectively employed for metal-catalyzed asymmetric aziridination,[4] catalytic processes based on the use of other types of azides, such as aryl azides, have been less developed. In addition to generating environmentally friendly nitrogen gas as the only byproduct, asymmetric catalytic aziridination with readily available aryl azides provides an attractive approach for the synthesis of valuable N-aryl aziridines through direct introduction of N-aryl groups concurrently with the ring formation.[5,6] This would avoid two additional steps of deprotection and N-arylation when other types of nitrene sources are used for preparing N-aryl aziridines.[7] However, few catalytic systems have been shown to be effective for asymmetric olefin aziridination with aryl azides.[4d,6]

A high temperature solution processing method was adapted to prepare durable, freestanding, submicrometer thickness films for transmission infrared spectroscopy studies of ionomer membrane. The materials retain structural integrity following cleaning and ion-exchange steps in boiling solutions, similar to a commercial fuel cell membrane. Unlike commercial membrane, which typically has thicknesses of25 μm, the structural properties of the submicrometer thickness materials can be probed in mid-infrared spectral measurements with the use of transmission sampling. Relative to the infrared attenuated total reflection (ATR) technique, transmission measurements can sample ionomer membrane materials more uniformly and suffer less distortion from optical effects. Spectra are reported for thermally processed Nafion and related perfluoroalkyl ionomer materials containing phosphonate and phosphinate moieties substituted for the sulfonate end group on the side chain. Band assignments for complex or unexpected features are aided by density functional theory (DFT) calculations.