TiO2／Ti／TiO2半导体隔片光电化学电池的性能

研究了半导体隔片光电化学电池(SC-SEP)中光池溶液的pH、暗池溶液的氧化还原电对以及两池中的暗电极对电池的开路电压、光生电压、短路光电流和光伏安特性的影响。对它们的影响机制进行了初步分析。通过合理选择电池体系,SC-SEP的性能可比单隔室的光电化学电池(PEC)优越。     

Carbonyl allylation of aldehydes catalyzed by a silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex

A silica-supported poly-γ-diphenylarsinopropylsiloxane palladium(0) complex has been prepared from γ-chloropropyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide and palladium chloride, and then the reduction with hydrazine hydrate. The palladium(0) complex has been found to catalyze the allylation of aldehydes via the formation of π-allylpalladium complexes, using allylic chlorides as allylating agent and SnCl₂ as reducing agent. This polymeric palladium complex can be recovered and reused.     

RNA Methylation m6A: A New Code and Drug Target?

The m⁶A‐RNA modification is a dynamic and reversible process, which has emerged as a new RNA code for the regulation of gene expression. The functional network of methyltransferases (writers), demethylases (erasers), and binding proteins (readers) modulate the level of m⁶A modification. Dysfunction of RNA methylation has been associated with various fundamental biological processes and human diseases. Herein, we briefly introduce an understanding‐enabled manipulation on m⁶A‐RNA modification with an emphasis on the use of small‐molecule intervention.      

Preparation and Characterization of Nanoscopic Organic Semiconductor of Oxovanadium Phthalocyanine

Nanoscopic particles of oxovanadium phthalocyanine (VOPc, phase-II) with different particle sizes are prepared by aggregation of VOPc molecules in the presence of surfactants for the first time. A size effect in the region of nanoscale was observed in the UV-visible spectra. The photoconductivity of the nanoscopic VOPc is much higher than that of bulk VOPc. Copyright 1999 Academic Press.     

Reactivity of organolanthanide and organolithium complexes containing the guanidinate ligands toward isocyanate or carbodiimide: synthesis and crystal structures

The direct reactions of (C5H5)2LnCl with LiN=C(NMe2)2 proceeded at room temperature in THF under pure nitrogen to yield the lanthanocene guanidinate complexes [(C5H5)2Ln(mu-eta1:eta2-N=C(NMe2)2)]2 (Ln = Gd (1), Er (2)). Treatment of phenyl isocyanate with complexes 1 and 2 results in monoinsertion of phenyl isocyanate into the Ln-N(mu-Gua) bond to yield the corresponding insertion products [(C5H5)2Ln(mu-eta1:eta2-OC(N=C(NMe2)2)NPh)]2 (Ln = Gd (3), Er (4)), presenting the first example of unsaturated organic small molecule insertion into the metal-guanidinate ligand bond. Further investigations indicate that N,N'-diisopropylcarbodiimide does not react with complexes 1 and 2 under the same conditions; however, it readily inserts into the lithium-guanidinate ligand bond of LiN=C(NMe2)2. As a synthon of the insertion product Li[(iPrN)2C(N=C(NMe2)2)], its reaction with (C5H5)2LnCl gives the novel organolanthanide complexes containing the guanidinoacetamidinate ligand, (C5H5)2Ln[(iPrN)2C(N=C(NMe2)2)] (Ln = Yb (5), Er (6), Dy (7)). All complexes were characterized by elemental analysis and spectroscopic properties. The structures of complexes 1, 3, 5 and 7 were determined through X-ray single-crystal diffraction analysis.     

Synthesis Hexadecyl 3-{4-[2-Hydroxy-3（isopropylamino）propoxy]phenyl}propionate as Potential Ligand for Liposome Targeting to Ischemic Myocardium

Novel hexadecyl 3- { 4-[2-hydroxy-3（isopropylamino）propoxy]phenyl }propionate （HPP）was synthesized and its effect on delivery of liposomes into cultured cardiomyocytes was examined. The structure of HPP was characterized by IH NMR, 1R and MS. The amount of cardiomyocytes uptake of HPP-liposome was 3.9-fold higher than plain-liposome, and the increase was 6.2-fold when hypoxia happens. It indicated that HPP was a potential ligand for liposome targeting to ischemic myocardium.     

Determination of butyltin compounds in sediments using an improved aqueous ethylation method

We have determined tributyltin and dibutyltin species in various environmental sediment samples (marine, harbour and river sediment) using the in situ aqueous ethylation-gas chromatography-atomic absorption spectrometry method subsequent to extraction by methanol containing O.5M HCl. The present technique provides a significantly lower detection limit than previous methods, so that tributyltin can for the first time be measured in some of the samples. Thus, the method described is well suited for the determination of tributyltin and dibutyltin compounds in sediments with low levels of butyltin species (e.g., Main River, 1.7 ng of tributyltin as Sn/g dry sediment).     

Syntheses and structural characterizations of Fe4S4 cubane-like cluster compounds containing cycloalkylthiolate ligands

In a reaction system consisting of FeCl₂, tetrathiometallate and cycloalkylthiolate, two Fe₄S₄ cubanelike cluster compounds were obtained with the following crystallographic data: (PhCH₂NMe₃)₂ [ Fe₄S₄ (SC₅H₉)₄] (I), monoclinic space groupP2₁/c,a = 1.632 7(4),b=1.122 9(3),c = 2. 802 5(10) nm, β= 94.63(2)°, Z=4, andR= 0.074; (Et₄N)₂[F₄S4(SC₆H_lI)₄] (II), tetragod space group ,a = l.167 05(9),b = 1.167 06(2),c = 2.063 26(5) nm,Z = 2, D_obs = 1. 28 g/cm³, andR = 0. 078. The participation of cycloalkylthiolate ligand does not obviously arouse the change of the Fe₄S₄ core structure. Meanwhile, the influence of the cation on the structural symmetry of the Fe₄S₄ cluster dianion is also discussed. Project supported by the National Natural Science Foundation of China and the Climbing Program Foundation of China.     

The phenomenon of conglomerate crystallization. Part 40: The crystallization behavior oftrans- Co(III) amines (+)546-trans-[Co(3,2,3-tet)(NO2)2]Cl·3H2O (I), (−)589 -trans-[Co(3,2,3-tet)Cl2]NO3 (II), and of (+)546-trans-[Co(3,2,3-tet)(NO2)2]NO3 (III)

A racemic solution of (I) crystallizes as a conglomerate from which a crystal we selected was found to be (+)₅₄₆-trans-[Co(3,2,3-tet)(NO₂)₂]Cl·3H₂O (I), CoClO₇N₆C₈H₂₈. It crystallizes in the enantiomorphic space groupP2_l2_l2_l, with lattice constantsa=18.501(15) å,b=14.433(2) å, andc=6.441(3) å;V=1720.07 å³ andd(calc. M.W.=414.73,Z=4)=1.601 g cm^?3. A total of 2305 data were collected over the range of 4?≤2θ ≤55?; of these, 1724 (independent and withI > 3σ(I)) were used in the structural analysis. Data were corrected for absorption (Μ=11.920 cm^?1), and the relative transmission coefficients ranged from 0.8258 to 0.9565. Refinement was carried out for both lattice enantiomorphs, and at this stage theR(F) andR _w (F) residuals were, respectively, 0.0381 and 0.0479 for (+ + +) and 0.0448 and 0.0532 for (? ? ?). Thus, the former was selected as correct for our specimen, and the final cycle of refinement with the (+ + +) model converged toR(F) andR _w (F) of 0.0315 and 0.0365. A racemic solution of (II) crystallizes as a conglomerate from which a crystal we selected was found to be (?)₅₈₉-trans-[Co(3,2,3-tet)Cl₂]NO₃ (II), CoCl₂O₃N₅C₈H₂₂. It crystallizes in the enantiomorphic space groujp,P2_l with lattice constantsa=6.395(2) å,b=8.886(2) å,c=13.185(2) å, andΒ=99.24(2)?;V=739.59 å³ andd(calc. M.W.=366.14,Z=2)=1.646 g cm ^?3. A total of 2912 data were collected over the range of 4?<2θ<64?; of these, 2147 (independent and withI≥3σ(I)) were used in the structural analysis. Data were corrected for absorption (Μ =15.424 cm^?1), and the relative transmission coefficients ranged from 0.9632 to 0.9985. Refinement was carried out for both lattice enantiomorphs, and the finalR(F) andR _w (F) residuals were, respectively, 0.0326 and 0.0328 for (+ + +) and 0.0347 and 0.0348 for (? ? ?). Thus, the (+ + +) was selected as correct for our specimen. A racemic solution of (III) crystallizes as a conglomerate from which a crystal we selected was found to be (+)₅₈₉-trans-[Co(3,2,3-tet)(NO₂)₂]NO₃ (III), CoO₇N₇C₈H₂₂. It crystallizes in the enantiomorphic space group,P2_l with lattice constantsa=6.295(1) å, b=15.108(3) å,c=8.029(1) å, andΒ=100.28(2)?;V=751.35 å³ andd(calc. M.W.=387.24,Z=2)=1.712 g cm^?3. A total of 2393 data were collected over the range of 4?≤2θ≤60?; of these, 1869 (independent and withI≥3σ(I)) were used in the structural analysis. Data were corrected for absorption (Μ=11.859 cm^?1), and the relative transmission coefficients ranged from 0.8814 to 0.9976. Refinement was carried out for both lattice enantiomorphs and the finalR(F) andR _w (F) residuals were, respectively, 0.0463 and 0.0482 for (+ + +) and 0.0441 and 0.0442 for (? ? ?). Thus, the latter was selected as correct for our specimen, and the final cycle of refinement with the (? ? ?) model converged toR(F) andR _w (F) of 0.0436 and 0.0421. For all three compounds, the six-membered rings are chairs; the secondary nitrogens are chiral centers, and the five-membered rings are ordered and conformationally dissymmetric, as expected. Coincidentally, in (I), (II), and (III) the central rings are right-handed helices withδ(+50.0?),δ(+53.3?), andδ(+48.3?), respectively. Thus, the secondary nitrogens of all three cations are (R), rendering the cations chiral. The incidence of conglomerate crystallization intrans coordination compounds is rare, and those known are asymmetrically substituted (see Ref. 4 for the four known cases). Thus, the incidence of such crystallization mode in a new series of [trans- Co(amine ligands)X₂]⁺ cations bearing symmetrical pairs oftrans ligands was an unexpected and welcomed event. In all three cases, the counteranions are bonded to the hydrogens of the terminal -NH₂ moieties, thus forming an overall entity which resembles a macrocycle. In fact, parallels between the crystallization behavior of our compounds and that of macrocycles bearing related fragments is discussed. Finally, in the three compounds, homochiral cations are linked into infinite strings by hydrogen bonds between the axial ligands and amino hydrogens on adjacent cations of the string. In turn, strings are stitched together by the counteranions which form bonds with amino hydrogens on cations of adjacent strings.