Bis- and tris-pyridyl amino and imino thioether Cu and Fe complexes. Thermal and microwave-assisted peroxidative oxidations of 1-phenylethanol and cyclohexane in the presence of various N-based additives
摘要:
The new [Cu(OTf)(L)](OTf) 1, [Cu(L)(H2O)](OTf)(2) 1', [Cu(OTf)(L-Me)](OTf) 2 and [Cu(L-py)](OTf)(2) 4, and [Fe(OTf)(2)(L-Me)] 3 and [Fe(OTf)(L-py)](OTf) 5 complexes, bearing bis- and tris-pyridyl amino and imino thioether ligands, have been synthesized and fully characterized by IR, ESI+-MS and elemental analyses, and also by X-ray diffraction structural analyses (for 1, 1', 2 and 4). In the presence of various N-based additives, they show a very good catalytic activity for the solvent- and halogen-free microwave-assisted oxidation of 1-phenylethanol by t-BuOOH (model reaction). The combination of pyridazine with the Cu complex 2 provided the most efficient catalytic system, resulting in a maximum yield of acetophenone of 99% after 30 min at 80 degrees C. The maximum turnover frequency (TOF) of 5220 h(-1) (corresponding to 87% yield) was achieved just after 5 min of reaction time under the very low microwave power of 10W. The catalytic properties of those complexes were also evaluated for the mild oxidation of cyclohexane, to cyclohexanol and cyclohexanone, in acetonitrile with H2O2, leading to yields up to 29% (based on the alkane substrate) that are comparable to the best reported Fe and Cu catalytic systems. The effects of various factors, such as nature and amount of the additives and metal centres (Cu or Fe), temperature, time and type of peroxide used, were also investigated. (C) 2011 Elsevier B.V. All rights reserved.
The compounds are ethylene derivatives which are inhibitors of histamine activity, in particular, inhibitors of H-2 histamine receptors. A compound of this invention is 1-nitro-2-[2-((4-methyl-5-imidazolyl)methylthio)ethylamino]-2-[2-((3-chlor o-2-pyridyl)methylthio)ethylamino]ethylene.
Deposition of new thia-containing Schiff-base iron (III) complexes onto carbon nanotube-modified glassy carbon electrodes as a biosensor for electrooxidation and determination of amino acids
Multiwallcarbonnanotubes (MWCNTs) were used as an immobilization matrix to incorporate an Fe (III)–Schiff base complex as an electron-transfer mediator onto a glassy carbon electrode surface. First, the preheated glassy carbon was subjected to abrasive immobilization of MWCNTs by gently rubbing the electrode surface on filter paper supporting the carbonnanotubes. Second, the electrode surface was
多壁碳纳米管(MWCNT)用作固定基质,将Fe(III)–Schiff碱配合物作为电子转移介体掺入玻璃碳电极表面。首先,通过在支撑碳纳米管的滤纸上轻轻摩擦电极表面,对预热的玻璃碳进行MWCNT的磨料固定。其次,通过浇铸100μLFe(III)络合物溶液(ACN中为0.01 M)来修饰电极表面。水溶液中修饰电极的循环伏安图显示了一对定义明确,稳定且几乎可逆的具有表面受限特性的还原氧化还原系统。MWCNTs和Fe(III)-Schiff碱配合物独特的电子和电催化性能的组合产生了显着的协同增效作用。通过循环伏安法表征了修饰电极在pH 1–9的水溶液中的电化学行为和稳定性。表观电子传递速率常数(K s)和传递系数(a)通过循环伏安法测定,分别约为7 s -1和0.55。修饰的电极在酸性溶液中具有非同寻常的正电位,对氨基酸的氧化表现出出色的催化活性。它们还显示出在宽pH范围,快速响应时间,高灵敏度,
Synthesis, spectroscopic characterization and antibacterial activity of new cobalt(II) complexes of unsymmetrical tetradentate (OSN2) Schiff base ligands
作者:Lotf Ali Saghatforoush、Firoozeh Chalabian、Ali Aminkhani、Ghasem Karimnezhad、Sohrab Ershad
DOI:10.1016/j.ejmech.2009.06.015
日期:2009.11
Cobalt ion complexes with the Schiff bases, (4-X-2-[2-(2-pyridine-2-yl-ethylsulfanyl)ethylimino]methyl}phenol (X = methoxy (OMe), phenylazo (N2Ph), bromo (Br), nitro (NO2)),were synthesized and investigated by several techniques using elemental analysis (C, H, N), FTIR, electronic spectra and molar conductivity. The thermal stability of free ligands and related cobalt complexes were studied by using
(<i>S</i>)-(2-(2‘-Pyridyl)ethyl)cysteamine and (<i>S</i>)-(2-(2‘-Pyridyl)ethyl)-<scp>d</scp>,<scp>l</scp>-homocysteine as Ligands for the “<i>fac</i>-[M(CO)<sub>3</sub>]<sup>+</sup>” (M = Re, <sup>99m</sup>Tc) Core
of fac-[NEt(4)](2)[Re(CO)(3)Br(3)] with (S)-(2-(2'-pyridyl)ethyl)cysteamine, L(1), in methanol leads to the formation of the cationic fac-[Re(CO)(3)(NSN)][Br] complex, 1, with coordination of the nitrogen of the pyridine, the sulfur of the thioether, and the nitrogen of the primary amine. When fac-[NEt(4)](2)[Re(CO)(3)Br(3)] reacts with the homocysteine derivative (S)-(2-(2'-pyridyl)ethyl)-d,l-homocysteine
coordination sphere while the carboxylate group remains free. At tracer level, the analogous complex fac -[ 99mTc(NSN)(CO) 3 ] + , 3 , was obtained in high yield by reacting ligand 1 with the fac -[ 99mTc(H 2 O) 3 (CO) 3 ] + precursor at pH 6.5. The structure of 3 was established by HPLC comparison to the prototype rhenium complex 2. Complex 3 is stable in solution as well as in the presence of strongly