A Novel Flow Injection Chemiluminescence System for the Determination of Reserpine

A novel flow injection cheminescence (FICL) system for the determination of reserpine is presented in this paper. It is based on the CL reaction of reserpine, IO - 4 and H 2O 2 in H 2SO 4 medium. The CL intensity was correlated with concentration of reserpine in the range of 1.0×10 -6～1.0×10 -4 g/mL with a detection limit of 1.35×10 -7 g/ mL. The relative standard deviation is 2.63% for 11 measurements of 2×10 -5 g/mL reserpine standard solution. The method has been applied to the determination of reserpine in pharmaceutical preparations and the results are in good agreement with that of the standard method.

Mechanisms of Fluorescence Quenching of Pr^(3+)-Doped PbWO_4 Crystal

Fluorescence decay curves of the ^3P0 and ^1D2 manifolds in Pr^3＋ doped PbWO4 crystal were measured at room temperature and fluorescence lifetimes of both manifolds were estimated. Combining with the radiative lifetimes of the manifolds calculated on the basis of the modified J-O theory, the main mechanisms for the fluorescence quenching of the manifolds were analyzed. The multi-phonon relaxation and the cross-relaxation energy transfer are the major reasons for the fluorescence quenching of the ^3P0 and ^1D2 manifolds, respectively. The Inokuti-Hirayama model was used to analyze the fluorescence decay curve of the ^1D2 manifold and the cross-relaxation of dlpole-dipole interaction was confirmed. Consequently, the ^3p0 manifold is more favorable as an upper laser level than the ^1D2 manifold.

Hydrophobic nanochannel self-assembled by amphipathic Janus particles confined in aqueous nano-space

Hydrophobic nanochannel plays a significant role in many physical, biological, and geological phenomena and ex- hibits impressive applications due to both its ubiquitous distribution and great ability to transport hydrophobic molecules, including various oils and gases. Based on theoretical modeling, we herein reveal that the amphipathic Janus nanoparticles have a large probability to self-assemble into uninterrupted hydrophobic nanochannels inside the aqueous nano-space, al- though there are large portions of the Janus nanoparticles to be hydrophilic. The key to this observation is the attractions between the hydrophobic regimes on neighboring amphipathic Janus particles through hydrophobic interaction in aqueous nano-space. More surprisingly, the permeation efficiency of hydrophobic molecules through the uninterrupted hydrophobic channel in Janus particles aggregate is even higher than that in the aggregate of hydrophobic particles. We note that the proposed amphipathic Janus particles can be transported to the appropriate positions by the water since the hydrophilic regimes still remain a strong particle-water interaction. We also note that most natural subsurface rocks are not completely hydrophobic or hydrophilic but have complex surfaces with inhomogeneous wetting property. Our work therefore provides a detailed molecular level understanding of the formation of underground strata as well as the new insight for constructing the artificial hydrophobic channels for various applications, such as the design of proppants to enhance the recovery of the unconventional oil/gas.

Electro.chemical Synthesis of （Aza）indolines via Dehydrogenative [3＋2] Annulatnon： Application to Total Synthesis of （±）-Hinckdentme At

An electrochemical synthesis of functionalized （aza）indolines through dehydrogenative [3＋2] annulation of arylamines with tethered alkenes has been developed. Previous reported syntheses through similar inter- and intramolecular annulation reactions required noble-metal catalysts and are mostly limited to terminal alkenes or 1,3-dienes. The electrosynthesis employs the easily available and inexpensive ferrocene as the molecular catalyst and is compatible with di-, tri- and even tetrasubstituted alkenes to construct indolines as well as the more challenging azaindolines. Employing the newly developed electrosynthesis as a key step, the total synthesis of marine alkaloid （＋）-hinckdentine A has been achieved in 12 steps （longest linear sequence） from commercially available materials.

Chromium trioxide modified spiro-OMeTAD for highly efficient and stable planar perovskite solar cells

Hole transporting materials(HTMs)play an unparalleled role in heightening the stability and photovoltaic performance of perovskite solar cells(PSCs).The organic small molecule spiro-OMeTAD is frequently utilized for HTM in PSCs.However,the raw spiro-OMeTAD without dopant would be harmful to the development of highly efficient PSCs,due to its unsatisfied hole mobility and conductivity.Therefore,we introduce an inorganic dopant(chromium trioxide,CrO_(3))into the lithium-salt doped spiro-OMeTAD.Because of the exclamatory oxidizability of CrO_(3),it can accelerate the oxidation of spiro-OMeTAD and thereby enhancing the hole mobility of HTM.The introduction of CrO_(3) not only substantially decreases the density of defects,but also adjusts spiro-OMeTAD energy band,and thus effectively suppresses the hysteresis and improving stability of PSCs.In the end,we obtained a power conversion efficiency(PCE)as high as 22.6%after doping CrO_(3) in spiro-OMeTAD.The facile,low cost and outstanding photovoltaic performance render CrO_(3) an excellent dopant for HTMs in PSCs.

Synthesis, chirality proof and crystal structure of chiral tetrahedral clusters

Each of the four vertices in chiral tetrahedral hetero-nuclear metal carbonyl clusters SFeCoM（CO）8Cp′（Ⅲ-V） is chemically different and no symmetric element could be derived from prochiral cluster SFeCo2（CO）9（Ⅰ）. Its single optically active cluster obtained by suitable method could be served as a model catalyst for asymmetric catalysis.

Heterometallic Trinuclear Carbonyl Sulfido Clusters and the Tetranuclear Intermediate via Electrophilic Addition-Elimination Reaction

The reaction of HFe_2Co(CO)_9(μ_3-S)with(η~5-C_5H_4CH_3)Mo(CO)_3CI has been carried out in refluxing tetrahydrofuran(THF)to give out heterometallic trinuclear clusters(η~5-C_5H_4CH_3)MoFeCo- (CO)_8(μ_3-S)and(η~5-C_5H_4CH_3)_2Mo_2Fe(CO)_7(μ_3-S)by electrophilic addition-elimination reaction.Howev- er,(η~5-C_5H_4CH_3)Fe(CO)_2Cl reacted with HFe_2Co(CO)_9(μ_3-S)at room temperature to yield a tetranuclear cluster(η~5-C_5H_4CH_3)Fe_3Co(CO)_(11)(μ_4-S).The μ_4-S cluster could be used as an intermediate in confirmation of the mechanism of the electrophilic addition-elimination reaction.The syntheses,characterizations and X-ray crystal structures of these clusters are reported herein as well as the discussion on the reaction mecha- nism.