One-pot three-component regioselective synthesis of linear naphtho[2,3-b]-furan-4,9-diones

The regioselective three-component condensation reaction of 2-hydroxy-1,4-naphthoquinone with isocyanides in the presence of a variety of aldehydes offers an easy one-pot access to linear naphtho[2,3-b]-furan-4,9-dione derivatives. This method has the advantage of good yields, high regioselectivity, and uses readily accessible substrates and reagents. The elucidation of regiochemistry has been accomplished by X-ray determination of some representative compounds.     

Novel isocyanide-based four-component reaction: a facile synthesis of fully substituted 3,4-dihydrocoumarin derivatives

A novel isocyanide-based four-component reaction between a 2-hydroxybenzaldehyde, Meldrum's acid, an isocyanide, and an aromatic or an aliphatic alcohol efficiently provide 3,4-dihydrocoumarin derivatives in good to excellent yields without using any catalyst or activation. The reaction can be carried out as a simple one-pot protocol at room temperature.     

Iron(III) mixed-ligand complexes: Synthesis,characterization and crystal structure determination of iron(III) hetero-ligand complexes containing 1,10-phenanthroline, 2,2′-bipyridine,chloride and dimethyl sulfoxide, [Fe(phen)Cl3(DMSO)] and [Fe(bipy)Cl3(DMSO)]

Treatment of [Fe(bipy)Cl₄][bipy · H] (1) and [Fe(phen)Cl₄][phen · H] (3) (where bipy is 2,2′-bipyridine and phen is 1,10-phenanthroline) with dimethyl sulfoxide in methanolic solution produced [Fe(bipy)Cl₃(DMSO)] (2) and [Fe(phen)Cl₃(DMSO)] (4) (where DMSO is dimethyl sulfoxide), respectively. The resulting complexes were characterized by elemental analysis, IR, UV–Vis and ¹H NMR spectroscopies and by the X-ray diffraction method. These complexes are high spin with a spin multiplicity of 6.     

A facile three‐components,one‐pot synthesis of pyrimido[4,5‐d]pyrimidine‐2,5‐dione derivatives under microwave‐assisted conditions

Pyrimido[4,5‐d]pyrimidine‐2,5‐dione derivatives have been synthesized in high yields in a novel, onepot, and efficient process by condensation of 6‐amino‐3‐methyl‐2‐(methylthio)pyrimidin‐4(3H)‐one, aldehydes and urea under microwave‐assisted conditions.     

A Clean synthesis of spiro[indoline-3,9'-xanthene]trione derivatives

A simple, clean and efficient method for the synthesis of spiro[indoline-3,9'-xanthene]trione derivatives and spiro[acenaphthene-1,9'-xanthene]-1',2,8'(2'H,5'H)-trione by condensation reaction of dimedone and isatins or acenaphthene in aqueous media is reported.     

间位苯基桥联的锰（Ⅲ）双咔咯的合成、表征及催化氧化性质

通过间苯二甲醛与5-氟苯基二吡咯甲烷反应合成了一种新的间位苯基桥联的双咔咯1,并利用锰盐与自由咔咯反应制备了其锰的金属配合物2。采用紫外、质谱、核磁、XPS等手段对化合物进行了表征。以苯乙烯为底物考察了锰双咔咯2的催化氧化性质,探讨了时间、溶剂、氧源、轴向配体对催化反应的影响。结果表明以亚碘酰苯和间氯过氧苯甲酸为氧源时催化的主要产物为环氧苯乙烷,而以双氧水和叔丁基过氧化氢为氧源时则主要产物为苯甲醛;在极性溶剂中的催化氧化产率较高。轴向配体对催化氧化有促进作用,不同轴向配体对催化反应产率提高的顺序是：1-甲基咪唑 >吡啶 >咪唑。     

DNA binding and nuclease activity of cationic iron(IV) and manganese(III) corrole complexes

Cationic meso(4‐N‐methylpyridyl)‐based metallocorroles, μ‐oxo iron corrole dimer ( 1b ) and manganese corrole monomer ( 2b ), were synthesized and characterized. The interactions of these two metal corrole complexes with CT‐DNA were studied by UV–visible, fluorescence and circular dichroism spectroscopic methods, as well as by viscosity measurements. The results revealed that 1b interacts with CT‐DNA in a difunctional binding mode, i.e. non‐classical intercalation and outside groove binding with H‐aggregation, while 2b can interact with CT‐DNA via an outside groove binding mode only. The binding constants K_b of 1b and 2b were 4.71 × 10⁵ m ^?1 and 2.17 × 10⁵ m ^?1, respectively, indicating that 1b can bind more tightly to CT‐DNA than 2b . Furthermore, both complexes may cleave the supercoiled plasmid DNA efficiently in the presence of hydrogen peroxide or tert‐butyl hydroperoxide (TBHP), albeit 1b exhibited a little higher efficiency. The inhibitor tests suggested that singlet oxygen and high‐valent (oxo)iron(VI) corrole or (oxo)manganese(V) corrole might be the active intermediates responsible for the oxidative DNA scission. Copyright © 2014 John Wiley & Sons, Ltd.     

Plasmonic fractals: ultrabroadband light trapping in thin film solar cells by a Sierpinski nanocarpet

Plasmonic Sierpinski nanocarpet as back structure for a thin film Si solar cell is investigated. We demonstrate that ultra-broadband light trapping can be obtained by placing square metallic nanoridges with Sierpinski pattern on the back contact of the thin film solar cell. The multiple-scale plasmonic fractal structure allows excitation of localized surface plasmons and surface plasmon polaritons in multiple wavelengths leading to obvious absorption enhancements in a wide frequency range. Full wave simulations show that 109 % increase of the short-circuit current density for a 200 nm thick solar cell, is achievable by the proposed fractal back structure. The amount of light absorbed in the active region of this cell is more than that of a flat cell with semiconductor thickness of 1,000 nm.