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An efficient copper-catalyzed approach for the synthesis of C-I oxygenated indolizines at room temperature is described. The method could also be applied to the synthesis of indolizinones through a cyclization/1,2-migration of tertiary propargylic alcohols.

The dispersion and functionalization of oxidized multiwalled carbon nanotubes (MWCNTs) in Ti[O.sub.2] via an in situ sol-gel process is described. Discrete and individual nanotubes are observed with the help of atomic force microscopy (AFM) by casting the dilute dispersion of functionalized MWCNTs onto a hydrophilic Si surface.

The direct reaction of aronyl cyanides with zirconacyclopentenes was achieved under controlled reaction conditions. This method provided an extremely efficient and high-yield route for the synthesis of homoallyl ketones when the reaction was carried out at -50 degree Celsius.

We demonstrate the capabilities of a laser-coupled ion mobility mass spectrometer for analysis of peptide sequence and structure showing ultraviolet photodissodation (UVPD) spectra of mass and mobility selected ions. A Synapt G2-S mass spectrometer has been modified to allow photointeraction of ions post the mobility cell. For this work, we have employed a single wavelength laser, which irradiates at 266 nm. We present the unique capabilities of this instrument and demonstrate several key features. Irradiation of luteinizing hormone releasing hormone (LHRH), growth hormone releasing hexapeptide (GHRP-6), and TrpCage (sequence NLYIQWLKDGGPSSGRPPPS) yields extensive b- and y-type fragmentation as well as a- and c-type ions. In addition, we observe side chain losses, induding the indole group from tryptophan, and immonium ions. For negatively charged ions, we show the advantage of using collision-induced dissodation (CLD) post-UVPD: radical ions are produced following irradiation, and these fragment with higher effidency. Further, we have incorporated ion mobility and subsequent drift time gating into the UVPD method allowing the separate analysis of m/z-coinddent spedes, both conformers and multimers. To demonstrate, we selectively dissociate the singly charged dimer or doubly charged monomer of the peptide gramiddin A and conformers of the [M + 5H]S+ form of the peptide melittin. Each mobility selected form has a different "fingerprint" dissodation spectrum, both predominantly containing b and y fragments. Differences in the intensities of various loss channels between the two species were revealed. The smaller conformer of melittin has fewer cleavage sites along the peptide backbone than the larger conformer suggesting considerable structural differences. For gramiddin, a single laser shot UVPD discriminates between primary photodissociation and subsequent fragmentation of fragments. We also show how this modified instrument facilitates activated electron photodissociation. UVPD-IM-MS analysis serves both as a method for peptide sequencing for peptides of similar (or identical) m/z and a method for optical analysis of mobility separated spedes. [ABSTRACT FROM AUTHOR]

An efficient transition-metal-free fluoroarylation reaction of N-aryl diazoacetamides with NFSI (N-fluorobenzenesulfonimide) is described. This reaction directly provides 3-fluorooxindole derivatives in yields of 67-93% with high selectivity via a carbene-free process under mild reaction conditions. [ABSTRACT FROM AUTHOR]

We demonstrate flow-directed production of nanoparticles of the photoresponsive block copolymer poly(o-nitrobenzyl acrylate)-b-polydimethylacrylamide in a gas-liquid microfluidic reactor. Microfluidic formation produced a variety of morphologies dependent on flow rate, with spheres and short cylinders, then large compound micelles, then unique spooled cylinders appearing as flow rate increased. The higher excess free energy of spooled cylinders relative to the quiescent equilibrium state is evidenced by their faster off-chip relaxation times (~1 day) as compared to other flow-directed structures. Comparison of light-triggered dissociation of flow-directed nanoparticles prepared at two different flow rates shows faster disruption of nanoparticles prepared at the higher flow rate. The application of variable flow to direct both structure and responsivity suggests interesting possibilities for controlled microfluidic manufacturing of "smart" polymeric colloids. [ABSTRACT FROM AUTHOR]

Using a photosensitive hybrid hydrogel loaded with upconversion nanoparticles (UCNPs), we show that continuous-wave near-infrared (NIR) light (980 nm) can be used to induce the gel-sol transition and release large, inactive biomacromolecules (protein and enzyme) entrapped in the hydrogel into aqueous solution "on demand", where their bioactivity is recovered. This study is a new demonstration and development in harnessing the unique multiphoton effect of UCNPs for photosensitive materials of biomedical interest. [ABSTRACT FROM AUTHOR]

We demonstrate a novel strategy enabling the use of a continuous-wave diode near-infrared (NIR) laser to disrupt block copolymer (BCP) micelles and trigger the release of their "payloads". By encapsulating NaYF4:TmYb upconverting nanoparticles (UCNPs) inside micelles of poly(ethylene oxide)-block-poly(4,5-dimethoxy-2-nitrobenzyl methacrylate) and exposing the micellar solution to 980 nm light, photons in the UV region are emitted by the UCNPs, which in turn are absorbed by o-nitrobenzyl groups on the micelle core-forming block, activating the photocleavage reaction and leading to the dissociation of BCP micelles and release of co-loaded hydrophobic species. Our strategy of using UCNPs as an internal UV or visible light source upon NIR light excitation represents a general and efficient method to circumvent the need for UV or visible light excitation that is a common drawback for light-responsive polymeric systems developed for potential biomedical applications. [ABSTRACT FROM AUTHOR]

New thermal- and photoresponsive core−shell nanogel particles were obtained from self-assembly in aqueous solution of a double-hydrophilic block copolymer (DHBCP) of which the two blocks could be photo-cross-linked via the reversible photodimerization and photocleavage of coumarin moieties. The diblock copolymer, consisting of poly[N,N-dimethylacrylamide-co-4-methyl-[7-(methacryloyl)oxyethyloxy]coumarin] and poly[N-isopropylacrylamide-co-4-methyl-[7-(methacryloyl)oxyethyloxy]coumarin] (P(DMA-co-CMA)-b-P(NIPAM-co-CMA)), was synthesized by using reversible addition−fragmentation chain transfer (RAFT) polymerization. At T> LCST of the P(NIPAM-co-CMA) block, core−shell micelles were formed and UV light irradiation at λ > 310 nm resulted in cross-linking of both the micelle core of P(NIPAM-co-CMA) and the micelle shell of P(DMA-co-CMA); subsequent cooling of the solution to T< LCST gave rise to water-soluble, swollen nanogel particles. Upon UV light irradiation at λ < 260 nm, the decrease of cross-linking density could increase the swelling of nanogel particles by ∼23% in diameter. By alternating irradiation with the different wavelengths, the average hydrodynamic diameter of nanogel particles was tunable between ∼58 and ∼47 nm. Interestingly, upon further cooling of the solution, aggregation occurred for nanogel particles with a moderate cross-linking density (10%−40% dimerization of coumarin moieties). Therefore, such core- and shell-cross-linked nanogel could display both “intraparticle” LCST (solubility of polymer chains forming the core) and “interparticle” UCST (solubility of particles). The possible mechanism and the effect of dimerization degree on the UCST behavior were discussed. [ABSTRACT FROM AUTHOR]

Highly ordered two-dimensional (2D) mesoporous silicoboron carbonitride (SiBCN) materials were prepared by a double nanocasting approach using mesoporous SBA-15 silica as starting template. The latter was converted into its negative replica CMK-3 carbon template, which was subsequently impregnated with a boron-modified polysilazanes of the type [B(C 2H 4SiCH 3NCH 3) 3] n([C 14.4H 31.4N 4.1B 1.0Si 3.0] n) using a liquid-phase impregnation (LPI) process. The derived [B(C 2H 4SiCH 3NCH 3) 3] n-carbon composite was cross-linked under ammonia at 200 °C and then thermolyzed under nitrogen at 1000 °C to generate a SiBCN-carbon composite. The carbon template was subsequently removed through thermal treatment at 1000 °C in an ammonia atmosphere to generate ordered mesoporous structures. XRD and TEM analyses revealed that as a negative replica of the CMK-3 template, the obtained amorphous mesoporous material exhibited open, continuous, and ordered 2D hexagonal frameworks, whereas elemental analyses indicated the formation of materials with an empirical formula of Si 3.0B 1.0C 4.2N 3.5. The ordered mesoporous Si 3.0B 1.0C 4.2N 3.5material displayed high surface area (600 m 2g −1), high pore volume (0.61 cm 3g −1), and narrow pore size distribution (around 3.4 nm) and exhibited a relatively good thermal stability in air through heat-treatment to 1400 °C. [ABSTRACT FROM AUTHOR]

A gold(III)-catalyzed multicomponent coupling/cycloisomerization reaction of heteroaryl aldehydes, amines, and alkynes under solvent-free conditions or in water has been developed. This methodology provides rapid access to substituted aminoindolizines with high atom economy and high catalytic efficiency. Especially, the coupling of enantiomerically enriched amino acid derivatives produces the corresponding N-indolizine-incorporated amino acid derivatives without loss of enantiomeric purity. [ABSTRACT FROM AUTHOR]

We describe a simple and robust approach to fabricating an α-Fe 2O 3switchable surface. The hydrophobicity of α-Fe 2O 3nanostructures was observed for the first time. A remarkable surface wettability transition can be easily achieved by ultraviolet (UV) illumination. The distinctive properties of surface defects are disclosed by X-ray photoelectron spectroscopy (XPS) analysis. The nanoscale adsorption and photocatalytic properties of Fe 2+defects account for the highly amphiphilic character of the surfaces. We believe that the experiment will further the molecular-scale understanding and manipulation of the wetting behavior on smart devices. [ABSTRACT FROM AUTHOR]

Transarterial radioembolization (TARE) is a highly effective localized radionuclide therapy that has been successfully used to treat hepatocellular carcinoma (HCC). Extensive research has been conducted on the use of radioactive microspheres (MSs) in TARE, and the development of ideal radioactive MSs is crucial for clinical trials and patient treatment. This study presents the development of a radioactive MS for TARE of HCC. These MSs, referred to as 177 Lu-MS@PLGA, consist of poly(lactic- co -glycolic acid) (PLGA) copolymer and radioactive silica MSs, labeled with 177 Lu and then coated with PLGA. It has an extremely high level of radiostability. Cellular experiments have shown that it can cause DNA double-strand breaks, leading to cell death. In vivo radiostability of 177 Lu-MS@PLGA is demonstrated by microSPECT/CT imaging. In addition, the antitumor study has shown that TARE of 177 Lu-MS@PLGA can effectively restrain tumor growth without harmful side effects. Thus, 177 Lu-MS@PLGA exhibits significant potential as a radioactive MS for the treatment of HCC.