Electrodeposition of CuInSe2 films by an alternating double-potentiostatic method using nearly neutral electrolytes

One step electrodeposition with an alternating double-potentiostatic(DPSED) program was used to prepare CuInSe₂ thin films in nearly neutral aqueous electrolytes with sodium citrate complex. Linear sweep voltammetry(LSV) was measured to probe voltammetric properties of electrolytes with respect to Cu, In and Se individual precursor and their mixed solutions. Compositional and structural characteristics of the as-deposited and annealed films at 400 °C in Ar atmosphere for 0.5 h were analyzed by XRD and XPS. The results showed that reduction of Cu²⁺ to Cu⁺ at one potential point of ?800 mV and subsequently formation of CuIn alloy as well as metal In and amorphous Se at the other potential point of ?1400 mV were responsible for synthesis of CISe chalcopyrite. Composition self-regulation made DPSED films have three elements co-deposition and more uniform element distribution, which promoted chalcopyrite CISe formation.     

A new class of functionalized polyoxometalates: synthesis, structure and preliminary antitumor activity studies of three arylimido substituted hexamolybdates bearing a strong electron-withdrawing nitro group, (Bu4N)2[Mo6O18([triple bond]NAr)] (Ar = 3-NO2-C6H4, 2-CH3-4-NO2-C6H3, 2-CH3-5-NO2-C6H3)

Three novel mono-functionalized arylimido derivatives of hexamolybdate bearing the strongest electron-withdrawing nitro group, (Bu(4)N)(2)[Mo(6)O(18)([triple bond, length as m-dash]NAr)] (, and ), have been synthesized for the first time by an improved reaction of octamolybdate ion and 3-nitroaniline hydrochloride, 2-methyl-4-nitroaniline hydrochloride and 2-methyl-5-nitroaniline hydrochloride respectively with DCC (N,N'-dicyclohexylcarbodiimide) as a dehydrating agent. Complete assignments were achieved for the title compounds by elemental analysis, IR, (1)H NMR, UV/visible and single-crystal X-ray diffraction analyses. The preliminary antitumor activity test indicated that the title compounds have some effects on the cellular growth inhibition of K562 cells.     

Tandem addition/cyclization reaction of organozinc reagents to 2-alkynyl aldehydes: highly efficient regio- and enantioselective synthesis of 1,3-dihydroisobenzofurans and tetrasubstituted furans

The enantioselective addition of organozinc reagents to some 2-alkynyl benzaldehydes and the subsequent regioselective cyclization step was performed in one pot to form chiral 1,3-dihydroisobenzofurans with good product yields and excellent regio- and enantioselectivities. In the case of 2-alkynylcycloalkene aldehydes, tetrasubstituted furans were obtained in good product yields through a 1, 5-hydride shift of the preformed cyclization product.     

Scope of direct arylation of fluorinated aromatics with aryl sulfonates

The scope and limitations of direct arylation of fluorinated aromatics with aryl sulfonates was examined. Pd(OAc)(2), in the presence of MePhos and KOAc in THF, efficiently catalyzed the direct arylation of fluoro aromatics with aryl triflates under ambient conditions. Sterically hindered triflates and heteroaryl triflates gave good to excellent yields of the cross coupled products using a modified catalyst system which involves Pd(OAc)(2)-RuPhos at 100 °C. The direct arylation of electron deficient arenes with aryl mesylates is also established using Pd(OAc)(2)-SPhos as the catalyst in toluene-(t)BuOH at 120 °C.     

Synthesis and Biological Activities of Diosgenin-Triazole Conjugates with a 1,3-Dipolar Cycloaddition Reaction

Chemistry of Natural Compounds - A novel series of diosgenin-triazole conjugates (10a–d, 11a–c, 12a–c, 13a–c) was designed and synthesized as antifungal agents by using a...     

Effect of cage size on the third‐order optical properties of endohedral metallofullerenes Sc3N@C2n (2n = 68, 70, 78, and 80): A theoretical study

Geometrical structures of the investigated endohedral metallofullerenes Sc₃N@C_2n (2n = 68, 70, 78, and 80) were optimized at the B3LYP/6‐31G* level. The analyses of electronic structures display that the contribution of fullerene cage to the lowest unoccupied molecular orbital decreases as the cage size increases. Based on the optimized structures, the time‐dependent density functional theory combined with the sum‐over‐states method was used to investigate their nonlinear optical properties. Calculated third‐order polarizabilities γ and two‐photon absorption (TPA) cross‐section δ do not present the monotone variation with the size of fullerene cage, with largest γ of 0.48 × 10^?34 esu for Sc₃N@C₇₈ in static state, and largest δ of 12.374 GM for Sc₃N@C₇₀ in the wavelength of 902.5 nm. However, the obtained TPA resonant peaks shift red with the size of fullerene cage. By analyzing the electronic origin of the third‐order optical properties, it is found that the charge transfers from the fullerene cage to the encapsulated Sc₃N cluster make important contributions to the studied properties. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Branching pattern and sequence analysis of underivatized oligosaccharides by combined MS/MS of singly and doubly charged molecular ions in negative-ion electrospray mass spectrometry

We previously reported that sequence and partial linkage information, including chain and blood-group types, of reducing oligosaccharides can be obtained from negative-ion electrospray CID MS/MS on a quadrupole-orthogonal time-of-flight instrument with high sensitivity and without derivatization (Chai, W.; Piskarev, V.; Lawson, A. M. Anal. Chem. 2001, 73, 651-657). In contrast to oligonucleotides and peptides, oligosaccharides can form branched structures that result in a greater degree of structural complexity. In the present work we apply negative-ion electrospray CID MS/MS to core-branching pattern analysis using nine 3,6-branched and variously fucosylated oligosaccharides based on hexasaccharide backbones LNH/LNnH as examples. The important features of the method are the combined use of CID MS/MS of singly and doubly charged molecular ions of underivatized oligosaccharides to deduce the branching pattern and to assign the structural details of each of the 3- and 6-branches. These spectra give complimentary structural information. In the spectra of [M - H]-, fragment ions from the 6-linked branch are dominant and those from the 3-linked branch are absent, while fragment ions from both branches occur in the spectra of [M - 2H]2-. This allows the distinction of fragment ions derived from either the 3- or 6-branches. In addition, a unique D2beta-3 ion, arising from double D-type cleavage at the 3-linked glycosidic bond of the branched Gal core residue, provides direct evidence of the branching pattern with sequence and partial linkage information being derived from C- and A-type fragmentations, respectively.     

Distribution of samarium and ytterbium in rats measured by enriched stable isotope tracer technique and INAA

In the present study a method using enriched stable isotope tracer and instrumental neutron activation analysis (INAA) was developed to study the dynamic distribution of rare earth elements (REEs) in a variety of organs and tissues of Wistar rats. Stable isotopes ¹⁵²Sm and ¹⁶⁸Yb were selected as tracers for the experiment. Intravenously injected ¹⁵²Sm and ¹⁶⁸Yb in chloride form could be quickly absorbed and distributed in almost all the organs and tissues of interest, including liver, skeleton, kidney, spleen, heart, lung, testicle, and blood serum. Liver and skeleton had high ability to take up ¹⁵²Sm and ¹⁶⁸Yb under the experimental conditions, whereas the contents of the elements in other organs were generally lower than 2% of the given dose during the whole experimental period. The difference in distribution of ¹⁵²Sm and ¹⁶⁸Yb in the body was also discussed.     

Light intensity distribution of a new type of contact laser scalpel

The emergent light distribution of a new type of contact laser scalpel is measured in three different states using a light sensor. The relationship between the angle and the light intensity is analyzed. The results show that the strongest light is emitted from two sides and the front of the scalpel. The light from the front mainly plays a role of cutting. The light from two sides contributes to stanch the wound so as to remain a clear visual field during the surgery. It also helps to increase the cutting efficiency.     

Molecular assembly of mitogen-activated protein kinase module in ras-transformed NIH3T3 cell line

The ras, is a G-like protein that controls the mitogen-activated protein kinase (MAPK) pathway involved in control and differentiation of cell growth. MAPK is a key component of its signaling pathway and the aberrant activation may play an important role in the transformation process. To better understand roles of ras in the activation of MAPKs, we have established ras transformed NIH3T3 fibroblast cell line, and analyzed the MAPK module. The ras transformed cells formed numerous spikes at the edges of cells and showed loss of contact inhibition. The levels of ERK1/2 MAPKs as revealed by Western blot analysis were not significantly different between ras transformed and non-transformed cells. However, phosphorylation of ERK MAPKs and the level of MEK were significantly increased although the heavily expressed level of Raf-1, an upstream component of MAPK pathway was unchanged in ras transformed NIH3T3 cells. The sedimentation profile of the MAPK module kinases in a glycerol gradient showed the presence of a rather homogeneous species of multimeric forms of ERK1/2 and MEK as indicated by the narrow distribution peak areas. The broad sedimentation profile of the Raf-1 in a glycerol gradient may suggest possible heterologous protein complexes but the identification of interacting molecules still remains to be identified in order to understand the organization of the MAPK signal transduction pathway.