نتایج جستجو برای: oxygen bridged dihydropyrimidinone

تعداد نتایج: 215526  

2009
Hamid Reza Memarian Asadollah Farhadi

A new facile cost-effective method for the oxidation of acetyl and carboethoxy derivatives of 3,4dihydropyrimidin-2(1H)-ones (DHPMs) by using potassium peroxydisulfate in water as solvent under microwave irradiation has been developed. Whereas the presence of the acetyl group instead of the carboethoxy group in position 5 decreases the rate of oxidation, the nature of the additional subtituent ...

Journal: :Dalton transactions 2008
Bin Peng Qian-Shu Li Yaoming Xie R Bruce King Henry F Schaefer

For the saturated carbonyl trimer Ru(3)(CO)(12) theoretical methods predict a doubly bridged Ru(3)(CO)(10)(mu-CO)(2) structure to lie only 0.3 kcal mol(-1) above the unbridged global minimum in accord with the fluxional properties observed experimentally by carbon-13 NMR on the very stable unbridged Ru(3)(CO)(12). For M(3)(CO)(11) and M(3)(CO)(10) the global minima for the Fe, Ru, and Os deriva...

Journal: :Dalton transactions 2011
Yasuhiro Arikawa Naoki Matsumoto Taiki Asayama Keisuke Umakoshi Masayoshi Onishi

The hydroxido-bridged dinuclear ruthenium complex 4, which is supported by Tp ligands, has been prepared from protonation of the oxido-bridged dinuclear ruthenium complex 3. Additional protonation of 4, affording the aqua-bridged dinuclear ruthenium complex 5 in situ, and subsequent treatment with NO gave rise to the dicationic dinitrosyl complex 2. These indicate completion of the NO reduction...

Journal: :Chemical communications 2012
Kamaljit Singh Tarunpreet Singh Virk Jing Zhang Wei Xu Daoben Zhu

New, neutral, meso-substituted tetraoxa[22]annulene[2,1,2,1] aromatic macrocycles are synthesised and disclosed as new p-type semiconductors with reproducible bulk-like carrier mobility (as high as 0.40 cm(2) V(-1) s(-1)) on highly crystalline thin films deposited on octadecyltrichlorosilane modified SiO(2).

Journal: :Physical chemistry chemical physics : PCCP 2014
Denys Shevchenko Magnus F Anderlund Stenbjörn Styring Holger Dau Ivelina Zaharieva Anders Thapper

Two types of manganese oxides have been prepared by hydrolysis of tetranuclear Mn(iii) complexes in the presence or absence of phosphate ions. The oxides have been characterized structurally using X-ray absorption spectroscopy and functionally by O2 evolution measurements. The structures of the oxides prepared in the absence of phosphate are dominated by di-μ-oxo bridged manganese ions that for...

Journal: :The Journal of biological chemistry 2004
Karin L C Grönberg Nicholas J Watmough Andrew J Thomson David J Richardson Sarah J Field

The bacterial respiratory nitric-oxide reductase (NOR) catalyzes the respiratory detoxification of nitric oxide in bacteria and Archaea. It is a member of the well known super-family of heme-copper oxidases but has a [heme Fe-non-heme Fe] active site rather than the [heme Fe-Cu(B)] active site normally associated with oxygen reduction. Paracoccus denitrificans NOR is spectrally characterized by...

Journal: :The Journal of chemical physics 2009
Alexander S Gentleman Matthew A Addicoat Viktoras Dryza Jason R Gascooke Mark A Buntine Gregory F Metha

The experimental and theoretical adiabatic ionization energies (IEs) of the rhodium-holmium bimetallic clusters RhHo(2)O(n) (n=0-2) have been determined using photoionization efficiency spectroscopy and density functional theory (DFT) calculations. Both sets of data show the IE of RhHo(2)O to be significantly lower than the values for RhHo(2) and RhHo(2)O(2), which are found to be similar. This...

Journal: :Bioorganic & medicinal chemistry 2008
Lautaro D Alvarez Adriana S Veleiro Ricardo F Baggio María T Garland Valeria C Edelsztein Héctor Coirini Gerardo Burton

Three analogs of neuroactive steroids were prepared (4-6) in which 1,11- or 11,19-oxygen bridges give a constrained conformation. Their 3D structures were obtained by ab initio calculations and in the case of 3alpha-hydroxy-11,19-epoxypregn-4-ene-20-one (4), confirmed by X-ray analysis. Biological activity of the synthetic steroids was assayed in vitro using t-[(3)H]butylbicycloorthobenzoate as...

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