Synthesis, spectral, photolysis and electrochemical studies of mononuclear copper(II) complex with a new asymmetric tetradentate ligand: Application as copper nanoparticle precursor
摘要:
A copper(II) complex with asymmetric tetradentate Schiff base ligand, obtained by the single condensation of 1,2-diaminopropane with 2-hydroxy-5-methoxy benzaldehyde was prepared. The ligand and complex were characterized by their IR, UV-Vis, FT-IR, NMR spectra and CV. Crystal structures of the mononuclear copper complex have been obtained by X-ray diffraction studies which revealed to be distorted square planner coordination geometry. The spectral data confirm coordination of ligand to copper ion center. The redox properties of complex at different scan rates exhibit grossly similar features consisting of an electrochemically pseudo-reversible Cu(II)/Cu(I) reduction at ca. -0.97 V and pseudo-reversible Cu(I)/Cu(II) oxidation at ca. -0.81 V. The copper nanoparticles with average size of 73 nm were formed by thermal reduction of copper complex in the presence of triphenylphosphine. (C)0 2012 Elsevier B.V. All rights reserved.
Taqui Khan, M. M.; Shaikh, Z. A.; Kureshy, R. I., Polyhedron, 1992, vol. 11, p. 91 - 100
作者:Taqui Khan, M. M.、Shaikh, Z. A.、Kureshy, R. I.、Boricha, A. B.
DOI:——
日期:——
Facile, Efficient, and Diastereoselective Synthesis of Heterohelicene-like Molecules
作者:Wei Lin、Guo-Lan Dou、Ming-Hua Hu、Cheng-Pao Cao、Zhi-Bin Huang、Da-Qing Shi
DOI:10.1021/ol400154j
日期:2013.3.15
A concise and efficient route to new and interesting heterohelicene-like molecules has been developed through the one-pot, cascade reductive coupling reaction of o-hydroxydiimines or o-nitrodiimines and triphosgene in the presence of TiCl4/Sm. Purification of the final products only required a single recrystallization leading to high purity. High diastereoselectivity was also achieved, and two structures of the final products were confirmed by X-ray diffraction analysis.
Salicylidene-imine-zirconium(IV) complexes in combination with methylalumoxane as catalysts for the conversion of hexa-1,5-diene: adjusting of the catalytic activity
A variety of substituted Schiff base complexes of the composition ("salen")ZrCl2(thf)(1-21) were synthesized, with methylalumoxane ("MAO") activated and used for a systematic study of their catalytic activity towards hexa-1,5-diene ("salen": substituted salicylidene-ethylene-iminato ligands). Main product of the catalytic cycle is methylenecyclopentane. Dimers are only formed in minor amounts. The catalytic activity and selectivity of the Ziegler-Natta systems strongly depend on the nature and the position of the peripheric substituents in the Schiff base ligands. Electron-withdrawing substituents in para-position to the phenolate oxygen (5-position) decrease the catalytic activity. Improved activity and selectivity were obtained with electron-donating substituents in 5-position. Altering the ethylene bridge causes a lowering of the activity or inactivation. According to the X-ray analysis the metal center in the related complex (L)ZrCl2 (22) (L: N',N'-bis(ethylene)-N'-methyl-N,N"-bis(benzoylacetonatoimine) has a pentagonal-bipyramidal environment. The pentadentate Schiff base Ligand lies in the plane, and both chloro groups occupy the axial positions. In contrast to the catalytically active salene complexes 22 can not rearrange to form a species in which the both chlorides are cis to each other. Consequently 22 is catalytically inactive.
Syntheses, spectral, electrochemical and thermal studies of mononuclear manganese(III) complexes with ligands derived from 1,2-propanediamine and 2-hydroxy-3 or 5-methoxybenzaldehyde: Self-assembled monolayer formation on nanostructure zinc oxide thin film
Mononuclear Mn(III) complexes have been prepared via the Mn(II) reaction of an equimolar of Schiff-bases derived from reaction of 2-hydroxy-3-methoxybenzaldehyde or 2-hydroxy-5-methoxybenzaldehyde with 1,2-diaminopropane. Axial ligands L include: pyridine (py) and H2O. The resulting complexes have been characterized by FT-IR and UV-vis spectroscopy. The crystal structures of the complexes were determined and indicate that in the solid state the complex adopts a slightly distorted octahedral environment of the imine N and hydroxo O with the two axial ligands. The electrochemical reduction of these complexes at a glassy carbon electrode in acetonitrile solution indicates that the first reduction process corresponding to Mn-III-Mn-II is electrochemically quasi-reversible. Thermal stability of these complexes was determined by TG and DTG. Layers of these complexes were formed on nanostructure zinc oxide thin film and a red shift was observed when zinc oxide thin film is modified by complex. (C) 2011 Elsevier B.V. All rights reserved.