Spectrophotometric studies of the formation of charge transfer complex of iron(III) with N,N′-bis(2-pyridylmethylidene)-1,2-diiminoethane di-Schiff base ligand in methanol

The complex formation reaction between N,N′-bis(2-pyridylmethylidene)-1,2-diiminoethane (BPIE) di-Schiff base ligand as an electron donor and iron(III) chloride as an electron acceptor have been studied spectrophometrically in methanol at 28°C. The values of equilibrium constants, K and molar absorptivities, ε were obtained from the Benesi–Hildebrand, Scott and Foster–Hammick–Wardley equations. The results indicate the formation of 1?:?1 charge transfer complex. The absorption band energy of the complex, E _CT, the ionization potential of the BPIE Schiff base ligand, I ^D, and the Gibbs energy changes of the above reaction, ΔG ⁰, were calculated. Finally, the kinetics of the complex formation reaction were studied and was found to be second-order in each reactant. The values of the rate constants of the forward and reverse reactions k ₁ and k _?1 were determined.     

三臂ATRP引发剂的合成及应用

分别以三乙醇胺、三聚氰胺为原料,通过酰化反应合成了三种具有配体功能的三臂原子转移自由基聚合(ATRP)引发剂:三[2-(2-溴异丁酰氧基)乙基]胺,三[2-(4-氯甲基苯甲酰氧基)乙基]胺和2,4,6-三(2-溴异丁酰胺基)-1,3,5-三嗪,收率分别为81%,69%和83%。以三[2-(2-溴异丁酰氧基)乙基]胺既作引发剂又作配体进行甲基丙烯酸甲酯(MMA)的ATRP乳液聚合,结果表明反应前期与中期具有活性/可控特征。     

Synthesis,spectroscopic, thermal,and biological activities of mixed ligand complexes containing E-N′-(3,4,5-trimethoxybenzylidene)benzofuran-2-carbohydrazide and 2-aminothiophenol

Complexes [M(L)(L′)Cl?·?H₂O], where M?=?Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II), L?=?ligand derived from reaction between benzofuran-2-carbohydrazide and 3,4,5-trimethoxybenzaldehyde (TMeOBFC) and L′?=?2-aminothiophenol (2-atp), have been synthesized. The structures of the complexes have been proposed from analytical data, IR, UV-Vis, ¹H NMR, direct analysis in real time-mass spectra, ESR spectral data, magnetic, and thermal studies. The complexes are soluble in DMF and DMSO. Molar conductance values indicate that the complexes are non-electrolytes. Antibacterial and antifungal activities of the ligands and their metal complexes have been obtained against bacteria Escherichia coli and Staphylococcus aureus and against fungi Aspergillus niger and Aspergillus flavus.     

Two new lead(II) nitrite complexes,crystal structure of [Pb(phen)2(NO2)2] an eight-coordinate lead(II) complex

Two new lead(II) complexes containing nitrite, [Pb(L)₂(NO₂)₂], L?=?1,10-phenanthroline (phen) or 2,2′-bipyridine (bpy), have been synthesized and characterized. The crystal structure of [Pb(phen)₂(NO₂)₂] shows monomeric units. The coordination number is eight (four from “phen” ligands and four nitrite anions), weak interaction of lead(II) with oxygen atoms of adjacent molecules produce dimer units in the solid state. The arrangement of ligands exhibits a coordination hole around the lead(II), occupied possibly by a stereoactive lone pair of electrons on lead(II), and the coordination around lead is hemidirected. There is a π–π stacking interaction between the parallel aromatic rings that may help to increase the “gap” around lead(II).     

Binary and ternary oxorhenium(V) complexes: synthesis,characterization, and crystal structure

A series of anionic five-coordinate binary oxorhenium(V) complexes with dithiolato ligands, Bu₄N[ReO(L¹)₂] (1a), Bu₄N[ReO(L²)₂] (1b), and Bu₄N[ReO(L³)₂] (1c), and a series of neutral octahedral ternary oxorhenium(V) complexes of mixed dithiolato and bipyridine ligands, [ReO(L¹)(bpy)Cl] (2a), [ReO(L²)(bpy)Cl] (2b), and [ReO(L³)(bpy)Cl] (2c) (where L¹H₂ = ethane-1,2-dithiol, L²H₂ = propane-1,3-dithiol, L³H₂ = toluene-3,4-dithiol, and bpy = 2,2′-bipyridine), were isolated and characterized by physicochemical and spectroscopic methods. The solid state structure of 1c was established by X-ray crystallography. All the mononuclear oxorhenium(V) complexes are diamagnetic. The redox behavior of all the complexes has been studied voltammetrically.     

ELECTRON SPIN RESONANCE OF γ -IRRADIATED COBALT(III) COMPLEXES; ELECTRONIC AND SPIN STATES OF HOT COBALT(II) IONS

Abstract

ESR investigation of the γ -ray irradiated Co(III) complexes have been carried out. The identification and the classification of the irradiation products on the basis of the ESR signal patterns, and the electronic and the spin states of the products are discussed.

Co(III) complexes are reduced by the γ irradiation into Co(II) complexes, where the produced Co(II) ions have low spin configurations, S = ½. Authors refer to these particular spin states as hot ions.     

Di-radical dinuclear copper complex: synthesis,structure, and magnetic properties

The reaction of Cu(Ac)₂·4H₂O with 2-[(3,5-dichloro-2-hydroxy-benzylidene)-amino]-2hydroxymethyl-propane-1,3-diol (H₄L) and 4,4′-bipyridyl-N,N′-dioxide (4,4′-bipy-NO) in DMF under solvothermal conditions leads to the formation of a di-radical dinuclear copper complex [Cu₂(4,4′-bipy-NO)(dcdmap)₄] (1) (dcdmap is the anion of 2,4-dichloro-6dimethylaminomethyl-phenol, synthesized by an in situ reaction). Compound 1 was characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Complex 1 displays dominant anti-ferromagnetic interaction between oxyradicals and copper ion and oxyradical.     

Dicopper complex of p-tert -butylcalix8arene bearing acylhydrazone pendant domains

A dicopper complex of p-tert-butylcalix8 Atwood, JL, Barbour, LJ, Hardie, MJ and Raston, CL. 2001. Coord. Chem. Rev., 222: 3[Crossref], [Web of Science ®] , [Google Scholar]arene bearing eight salicylaldehyde acylhydrazone domains was prepared and its single crystal structure determined, in which only four acylhydrazone domains act as monoanionic tridentate planar chelators to coordinate to two copper ions.