共查询到20条相似文献,搜索用时 31 毫秒
1.
Jianfeng Jiang Wenfeng Lo Peter Müller Noam D. Fine Myrium Maruani Alexander Raytman 《Inorganic chemistry communications》2009,12(6):527-529
fac-[FeII(CO)3X3]1? (X = Br, I) are synthesized and their structures have been determined. They are the first crystallographically characterized iron tricarbonyl trihalide complexes. fac-[FeII(CO)3X3]1? (X = Br, I) are fairly thermally stable and therefore lead themselves as excellent starting materials for the preparation of various iron carbonyl complexes since both the halide and carbonyl ligands are substitutionally labile. 相似文献
2.
Yaqoub Ali Hamam Hasan Moh'd El Ghanem Issam Mahmoud Arafa Moh'd Rida Said Ibrahim Abo aljarayish 《Polymer International》2007,56(3):376-380
FeII, FeIII and mixed‐valence FeII–III chlorides were reacted with poly[N,N′‐bis(dimethylsilyl)ethylenedi‐ amine], [? Si(CH3)2NHCH2CH2NH? ]n, to form the corresponding Fe‐polycarbosilazane macromolecular complexes. The average chain–chain spacing in these materials was estimated from X‐ray diffraction data and found to be 6.94, 7.29, 7.30 and 7.45 Å in metal‐free and FeII? , FeIII? and FeII–III‐containing polycarbosilazanes, respectively. This demonstrates that FeII, FeIII and FeII–III chlorides are encapsulated between the polycarbosilazane chains. The chain–chain expansions in the divalent FeII and trivalent FeIII chloride macromolecular complexes are comparable, but less than that in the FeII–III chloride analog, which suggests that different chain–chain packings exist in the mixed‐valence macromolecular complex. The magnetic properties of the resulting complexes were investigated by measuring the magnetization in magnetic fields up to 8 kOe and in the temperature range from liquid nitrogen temperature to room temperature. Copyright © 2007 Society of Chemical Industry 相似文献
3.
Mohamed A. EL-Gahami Zaher A. Khafagy Azza M. M. Ali Nabwia M. Ismail 《Journal of Inorganic and Organometallic Polymers》2004,14(2):117-129
Mixed ligand complexes of CoII, NiII and CuII with dicarboxylic amino acids (aspartic, glutamic or H2ADA) as primary ligands and 8-hydroxyquinoline as a secondary ligand were prepared and characterized by elemental analysis, conductivity measurements, thermal analysis, cyclic voltammetry, and electronic and infrared (IR) spectroscopy. Cyclic voltammetry reveals a reversibility of the CuII/CuI couple, while the reactions of the CoII and NiII complexes are irreversible. All complexes have a metal-to-ligand ratios of 1:1:1 and octahedral structures are suggested to be attained by interactions among both of the amino acids and 8-hydroxyquinoline anions with the metal ions. The reaction orders and activation energies have been computed by means of the Coats–Redfern and Horowitz–Metzger equations. The biological activity of selected complexes as anti-fungal agents has been tested. 相似文献
4.
For the first time, it is attempted to interpret an experimentally found enhancing effect of cycloaliphatic substituents in aromatic rings of NiII- and PdII-α-diimine and FeII-bis(imino)pyridine ethylene polymerization precatalysts on their catalytic activities at elevated temperatures (60-80 °C), using quantum chemical density functional theory calculations of relative stabilities of the complexes with respect to different deactivation processes, including thermal decomposition and one-electron reduction. It was shown that the effect correlates with the calculated higher thermal stabilities of cycloalkyl-substituted FeII-, NiII- and PdII-complexes as compared to the corresponding alkyl-substituted ones. NiII- and PdII-α-diimine complexes with cycloalkyl substituents are shown to be more stable than their alkyl-substituted analogues with respect to both thermal decomposition and one-electron reduction. The averaged difference of the thermal decomposition energies between the complexes with cycloaliphatic substituents on one side and aliphatic ones on the other side is ∼2.3 kcal/mol, corresponding to ∼30 times lower equilibrium constant of the thermal decomposition reaction for the cycloalkyl-containing complexes. For the FeII- and PdII-complexes, the thermal stability correlates with the calculated overlap population of the metal-nitrogen bonds. It was shown that the structure of o-substituents (cycloalkyls vs. alkyls) in the phenyl rings of the ligands does not affect the reaction energies for the transformation reactions of the precatalysts into their corresponding active catalytic cationic forms. 相似文献
5.
《Inorganic chemistry communications》2003,6(2):193-196
The trinuclear manganese(II) complexes, [MnII3(OAc)4(pap)2(H2O)2] and [MnII3(OAc)4(5-Cl-pap)2(MeOH)2] were prepared by the reaction of tridentate Schiff base ligands X-papH (X=H, Cl), [N-2-pyridiylmethylidene-2-hydroxy-5-substituted-phenylamine], and MnII(OAc)2·2H2O. In the molecular structures of these complexes, two terminal manganese ions are coordinated with one oxygen and two nitrogen atoms of X-pap, two oxygen atoms of OAc− and a solvent molecule, to form a distorted octahedral structure where the central manganese ion resides on a center of symmetry and is surrounded by an O6 donor set of four oxygen atoms from four bridging OAc− and two phenolic oxygen atoms of two X-pap ligands. 相似文献
6.
A composite of silica sol-gel, generation-4 poly(amidoamine) dendrimer (PAMAM) and cobalt hexacyanoferrate (CoHCF) was synthesized as a potential electrochromic material. The solid-state voltammetry of the material had suggested that the two electroactive sites were present. To elucidate the redox properties, the electronic and the structure in the local atomic environment of Fe and Co was investigated by X-ray absorption spectroscopy (XAS). Although the nominal stoichiometries of the investigated CoHCFs were Co2IIFeII(CN)6 (or K2CoIIFeII(CN)6) and KCoIIFeIII(CN)6, the spectral data demonstrated that CoIII was present in the composite. Among the supporting evidence for some metal-to-metal electronic transition of FeIII-CN-CoII to FeII-CN-CoIII was the shortening of the measured Co-N bond length in accord with the formation of CoIII. Further, IR measurements confirm the occurrence of charge transfer between Fe and Co sites in the silica-PAMAM composite. 相似文献
7.
Hai-Ping Wang Hai-Gang Li Guang-Nong Lu Ning Tang Wei-Sheng Liu Yu Tang 《Inorganic chemistry communications》2010,13(7):882-886
Two novel ring-like rigid quinoline–amide ligands, 2-[2-(1,3-dioxolan-2-yl)quinolin-8-yloxy]-N-benzylacetamide (LI) and 3-[2-(1,3-dioxolan-2-yl)quinolin-8-yloxy]-1,1-diphenylpropan-2-one (LII), were designed to assemble the anion-responsive luminescent europium complexes. Crystallographic studies of the EuLI(NO3)3 and EuLII(NO3)3 revealed that the tetradentate ligands LI and LII cooperatively coordinated with Eu3+ ion and some available sites around central europium ions for guest anions were reserved in the complexes. The luminescent properties of the Eu(III) nitrate complexes in acetonitrile solutions were investigated. And the lowest triplet state energy levels of the ligands are well placed to allow energy transfer to the resonance level of Eu(III). At the same time, the luminescence titration experiments and the Job's plot analysis demonstrated the formation of 1:1 complexes in the solutions. The luminescence intensities at 616 nm were enhanced by addition of NO3? or Cl? anion to the mixed acetonitrile solutions of Eu(CF3SO3)3 and the ligands. 相似文献
8.
Katharina Butsch Alexander Haseloer Simon Schmitz Ingo Ott Julia Schur Axel Klein 《International journal of molecular sciences》2021,22(8)
The three complexes [Fe(opo)3], [Cu(opo)2], and [Zn(opo)2] containing the non-innocent anionic ligand opo− (opo− = 9-oxido-phenalenone, Hopo = 9-hydroxyphenalonone) were synthesised from the corresponding acetylacetonates. [Zn(opo)2] was characterised using 1H nuclear magnetic resonance (NMR) spectroscopy, the paramagnetic [Fe(opo)3] and [Cu(opo)2] by electron paramagnetic resonance (EPR) spectroscopy. While the EPR spectra of [Cu(opo)2] and [Cu(acac)2] in dimethylformamide (DMF) solution are very similar, a rather narrow spectrum was observed for [Fe(opo)3] in tetrahydrofuran (THF) solution in contrast to the very broad spectrum of [Fe(acac)3] in THF (Hacac = acetylacetone, 2,4-pentanedione; acac− = acetylacetonate). The narrow, completely isotropic signal of [Fe(opo)3] disagrees with a metal-centred S = 5/2 spin system that is observed in the solid state. We assume spin-delocalisation to the opo ligand in the sense of an opo− to FeIII electron transfer. All compounds show several electrochemical opo-centred reduction waves in the range of −1 to −3 V vs. the ferrocene/ferrocenium couple. However, for CuII and FeIII the very first one-electron reductions are metal-centred. Electronic absorption in the UV to vis range are due to π–π* transitions in the opo core, giving Hopo and [Zn(opo)2] a yellow to orange colour. The structured bands ranging from 400 to 500 for all compounds are assigned to the lowest energy π−π* transitions. They show markedly higher intensities and slight shifts for the CuII (brown) and FeIII (red) complexes and we assume admixing metal contributions (MLCT for CuII, LMCT for FeIII). For both complexes long-wavelength absorptions assignable to d–d transitions were detected. Detailed spectroelectrochemical experiments confirm both the electrochemical and the optical assignments. Hopo and the complexes [Cu(opo)2], [Zn(opo)2], and [Fe(opo)3] show antiproliferative activities against HT-29 (colon cancer) and MCF-7 (breast cancer) cell lines in the range of a few µM, comparable to cisplatin under the same conditions. 相似文献
9.
To mimic dinuclear active sites of metalloproteins, we have developed a dinucleating ligand system consisting of two tetradentate tripodal ligand compartments with varying terminal donors (carboxylates, phenolates, and pyridines). These ligands provide access to a series of μ-oxo-bridged diferric complexes. The spectroscopic study allows to investigate the molecular structures even in solution, e. g. depending on protonation/deprotonation of coordinated OH− and H2O ligands or to observe a reversible pH-dependent carboxylate-shift between terminal and bridging binding mode. The electrochemical behavior is strongly influenced by the exogenous ligands, e. g. OH− facilitates oxidation to FeIV by 690 mV relative to Cl−. Using the terminal carboxylates and a {FeIII(μ-O)2FeIII} core even allows oxidation with O2 to a high-valent species with FeIV (S=2). The implications of this study for further generation of high-valent or peroxo species and their utilization in catalysis is discussed. 相似文献
10.
Leticia Cubo Dr. Michael Groessl Dr. Paul J. Dyson Prof. Adoración G. Quiroga Dr. Carmen Navarro‐Ranninger Prof. Angela Casini Dr. 《ChemMedChem》2010,5(8):1335-1343
The reactivity of three cytotoxic trans‐PtII complexes bearing aliphatic amine ligands, with transferrin and single‐stranded oligonucleotides as DNA models, was investigated by ESI‐MS and the results obtained are discussed in comparison with cisplatin. Tandem MS studies provided additional information on the preferential Pt binding sites. To determine whether trans‐PtII complexes can migrate from a peptide to an oligonucleotide, transfer experiments were also performed using ESI‐MS, and competitive binding of the trans‐PtII complexes toward a model peptide and different oligonucleotides was also investigated. Significant differences in the reactivity of the trans complexes with respect to cisplatin were observed. In general, adduct formation with the selected peptide is favored for the trans compounds, whereas cisplatin shows a preference for oligonucleotides, especially if adjacent G–G residues are present. The results are discussed in relation to the possible mechanism of action of the trans‐PtII complexes. 相似文献
11.
Huriye Akdas-Kilig Jean-Pierre MalvalFabrice Morlet-Savary Anu SinghLoic Toupet Isabelle Ledoux-RakJoseph Zyss Hubert Le Bozec 《Dyes and Pigments》2012,92(1):681-688
Two new 4,4′-bis(donor)-6,6′-diphenyl- 2,2′-bipyridine ligands and their corresponding D2d (CuI, AgI, ZnII) octupolar metal complexes were synthesized, and their linear and nonlinear optical properties were investigated. A single crystal X-ray structure was also determined for the bis[4,4′-bis(diethylaminostyryl)-6,6′-diphenyl-bipyridine]copper(I) complex, which revealed a distorded pseudo-tetrahedral geometry. Molecular second-order nonlinear optical properties were determined for the complexes using the Harmonic Light Scatterring technique at 1.91 μm. These metallo-chromophores display large first hyperpolarizabilities β1.91 in the range of 211-340 × 10−30 esu, which increase with the Lewis acidity of the metal ion. The two-photon absorption properties of the bipyridyl ligands and related complexes were determined using either the two-photon emission method for fluorescent compounds or the open aperture Z-scan technique for non emissive ones. The complexes display red-shifted two-photon absorption bands compared to their metal-ion free chromophores, as well as a large increase of the maximum two-photon absorption cross-sections. 相似文献
12.
Catalytic oxidation of water-soluble tertiary amines by complexes of CuII, FeIII and CoII was utilized to initiate radical polymerization of N,N-dimethylacrylamide (DMAAm) in aqueous solution at 70–80 °C. The oxidation of tertiary amines by CuII was studied by proton nuclear magnetic resonance spectroscopy and online ultraviolet–visible spectrophotometry. The polymerization kinetics was monitored by gas chromatography, and molecular weight of the PDMAAm was measured by gel-permeation chromatography coupled with multi-angle laser light scattering. Oxidation of tertiary amines occurs predominantly via formation of Calpha·radicals to initiate polymerization of electron-deficient monomers and N-dealkylation, and redox equilibrium between CuI/L and CuII/L is established at a faster rate in aqueous media. FeIII and CuII complexes are efficient catalysts as each catalyst molecule could generate above 10 propagating radicals in 5 h, while CoII complex might involve in oxidation of tertiary amines in non-radical pathway, leading to a low catalytic efficiency. Water-soluble tertiary amines such as N,N-dialkylethanolamine (alkyl = methyl, ethyl etc.) are reducing agents of a higher activity in aqueous media than those primary or secondary analogues. Our strategy renders it possible to prepare polymer of alpha-amino functionality via one-pot process from commercially available commodity reagents under practical conditions with negligible catalyst residue. 相似文献
13.
《Catalysis communications》2002,3(9):405-410
NiII, CoII and FeII complexes of 2-(2-pyridyl)quinoxaline were synthesized and used in the ethylene oligomerization with methyl-aluminoxane (MAO) as cocatalyst. The nickel complex system mainly produced α-olefins with good activity, while the cobalt and iron complexes showed only marginal activity. 相似文献
14.
Hiromichi Aono Takaaki Nishida Masato Kurihara Masatomi Sakamoto Yoshihiko Sadaoka 《Ceramics International》2012,38(3):2333-2338
New heteronuclear (NH4)REIII[FeII(CN)6]·nH2O complexes (RE = La, Ce, Pr, Nd, Sm, Gd, Dy, Y, Er, Lu) were synthesized and their thermal decomposition products were investigated. The crystal structure of (NH4)RE[FeII(CN)6]·nH2O would be a hexagonal unit cell (space group: P63/m), which was the same as that of La[FeIII(CN)6]·5H2O. The hydration number n = 4 was estimated by TG results for all the RE complexes. The lattice constants depended on the ionic radius of the RE3+ ion for the heteronuclear complexes. The single phase of the perovskite type materials was directly obtained by decomposition of the heteronuclear complexes for RE = La, Pr, Nd, Sm, and Gd. A mixture of CeO2 and Fe2O3 was formed for RE = Ce because of its oxidation to Ce4+. In the case of RE = Dy, Y, Er, and Lu complexes, the perovskite type materials formed at higher temperature via. mixed oxides such as RE2O3 and RE4Fe5O13 due to the small RE3+ ionic radius. 相似文献
15.
Ji Chul Jung Howon Lee Jeong Gil Seo Sunyoung Park Young-Min Chung Tae Jin Kim Seong Jun Lee Seung-Hoon Oh Yong Seung Kim In Kyu Song 《Catalysis Today》2009,141(3-4):325
Multicomponent bismuth molybdate (MII9Fe3Bi1Mo12O51) catalysts with different divalent metal (MII = Mg, Mn, Co, Ni, and Zn) were prepared by a co-precipitation method, and were applied to the oxidative dehydrogenation of n-butene to 1,3-butadiene. Effect of divalent metal (MII) on the catalytic performance of MII9Fe3Bi1Mo12O51 catalysts was investigated. X-ray photoelectron spectroscopy (XPS) measurements were conducted to determine the oxygen mobility of MII9Fe3Bi1Mo12O51 catalysts. It was found that the catalytic performance of MII9Fe3Bi1Mo12O51 catalysts was closely related to the oxygen mobility of the catalysts. The yield for 1,3-butadiene was monotonically increased with increasing oxygen mobility of the catalysts. Among the catalysts tested, the Co9Fe3Bi1Mo12O51 catalyst with the highest oxygen mobility showed the best catalytic performance in the oxidative dehydrogenation of n-butene. 相似文献
16.
The synthesis, physico-chemical characterization and cytotoxicity of two di-iron(III) complexes toward three human leukemia cell lines (THP-1, U937 and Molt-4) are reported: [(Cl2)FeIII(μ-HL1)2FeIII(Cl2)]·3H2O (1) and [(Cl2)FeIII(μ-HL2)2FeIII(Cl2)] (2), where HL1 and HL2 are isomers and contain pyridine, phenol, amine and alcohol moieties with a naphthyl pendant unit. These compounds were characterized by a range of physico-chemical methods. Electrochemical studies reveal the maintenance of the dinuclear arrangement in solution, which is supported by ESI(+)-MS studies. Mossbauer spectra consist of a unique doublet indicating equivalent iron centers in the whole sample. The hyperfine parameters are typical of high-spin iron(III). Complex (1) is more active than complex (2), showing an effect of the isomerism on the antitumoral activity. The comparison between these data and those obtained for complexes containing copper and cobalt reveals that the isomerism of the ligand, the nature of the metal centers, the nuclearity and the kind of cell line exert a great influence on the biological activity. 相似文献
17.
Truc Lam Pham Sunnatullo Fazliev Philipp Baur Prof. Dr. Peter Comba Prof. Dr. Franziska Thomas 《Chembiochem : a European journal of chemical biology》2023,24(3):e202200588
The three-dimensional structure of a peptide, which determines its function, can denature at elevated temperatures, in the presence of chaotropic reagents, or in organic solvents. These factors limit the applicability of peptides. Herein, we present an engineered β-hairpin peptide containing a His3 site that forms complexes with ZnII, NiII, and CuII. Circular dichroism spectroscopy shows that the peptide−metal complexes exhibit melting temperatures up to 80 °C and remain folded in 6 M guanidine hydrochloride as well as in organic solvents. Intrinsic fluorescence titration experiments were used to determine the dissociation constants of metal binding in the nano- to sub-nanomolar range. The coordination geometry of the peptide−CuII complex was studied by EPR spectroscopy, and a distorted square planar coordination geometry with weak interactions to axial ligands was revealed. Due to their impressive stability, the presented peptide−metal complexes open up interesting fields of application, such as the development of a new class of peptide−metal catalysts for stereoselective organic synthesis or the directed design of extremophilic β-sheet peptides. 相似文献
18.
Three different complexes, heme-Cu ([(6L)FeIICuI]+ (1), 6L=a binucleating ligand having a heme and covalently tethered copper binding tris(2-pyridyl)methylamine tetradentate moiety), heme complex ((6L)FeII (4), (with “empty” tethered chelate)), and the “parent” iron-porphyrinate ((F8TPP)FeII (5), F8TPP=tetrakis(2,6-difluorophenyl)porphyrinate) were employed for the electrocatalytic reduction of O2. Complexes 1 and 4 reduce O2 to water (four-electron reduction) with good efficiency (74 and 59%, respectively), but complex 5 exhibited only an ∼20% efficiency, thus primarily the two-electron reduction to hydrogen peroxide occurred. The results of the present electrochemical O2-reduction studies and the previous studies have elucidated the O2-binding nature of these three complexes, indicating the formation of quite stable FeIII(O22−)CuII (peroxo) or FeIIIO2− (superoxo) species. In line with the thinking of other researchers, the fact that both 1 and 4 can well stabilize FeIIIO2− superoxo species may suggest that the formation of the latter is a key to the pathway favoring four-electron reduction of dioxygen to water. 相似文献
19.
Ashish Kumar Yadav Virendra Singh Rajesh Kushwaha Dr. Dependu Dolui Rohit Rai Dr. Prodyut Dhar Dr. Arnab Dutta Dr. Biplob Koch Dr. Samya Banerjee 《Chembiochem : a European journal of chemical biology》2023,24(10):e202300033
Four new CoII complexes, [Co(bpy)2(acac)]Cl ( 1 ), [Co(phen)2(acac)]Cl ( 2 ), [Co(bpy)2(cur)]Cl ( 3 ), [Co(phen)2(cur)]Cl ( 4 ), where bpy=2,2’-bipyridine ( 1 and 3 ), phen=1,10-phenanthroline ( 2 and 4 ), acac = acetylacetonate ( 1 and 2 ), cur=curcumin monoanion ( 3 and 4 ) have been designed, synthesized and fully characterized. The X-ray crystal structures of 1 and 2 indicated that the CoN4O2 core has a distorted octahedral geometry. The photoactivity of these complexes was tuned by varying the π conjugation in the ligands. Curcumin complexes 3 and 4 had an intense absorption band near 435 nm, which made them useful as visible-light photodynamic therapy agents; they also showed fluorescence with λem≈565 nm. This fluorescence was useful for studying their intracellular uptake and localization in MCF-7 breast cancer cells. The acetylacetonate complexes ( 1 and 2 ) were used as control complexes to understand the role of curcumin. The white-light-triggered anticancer profiles of the cytosol targeting complexes 3 and 4 were investigated in detail. These non-dark toxic complexes displayed significant apoptotic photo-cytotoxicity (under visible light) against MCF-7 cells through ROS generation. The control complexes 1 and 2 did not induce significant cell death in the light or dark. Interestingly, 1-4 produced a remarkable antibacterial response upon light exposure. Overall, the reported results here can increase the boundary of the CoII-based anticancer and antibacterial drug development. 相似文献
20.
S.A. Agnihotry Punita Singh Amish G. Joshi D.P. Singh K.N. Sood S.M. Shivaprasad 《Electrochimica acta》2006,51(20):4291-4301
The correlation between the temperature-dependent electrochromic (EC) activity and other properties of galvanostatically deposited Prussian Blue (PB) films is presented here. Films subjected to annealing treatment in air at temperatures up to 500 °C were characterized by a variety of techniques which include TGA, XRD, FTIR, UV-vis spectrophotometry, SEM, XPS, cyclic voltammetry etc. The as-deposited X-ray amorphous hydrated PB films were blue in color and had Fe in both FeII and FeIII valence states and were electrochromically active. Consequent to changes in the valence state, degree of hydration and coordination environment of the iron ions upon annealing, EC activity and morphology of the films exhibited dramatic changes. Annealing at moderate temperatures retained the blue color of the films and decreased the EC activity consistent with dehydration and decreased the FeII content. Lack of EC activity at higher temperatures was consistent with dehydration and quenching of FeII states accompanied with change of color from blue to rust (FeIII) typical of Fe2O3. Independent of the annealing temperature, the films retained their amorphicity, however, prolonged annealing at 500 °C yielded hexagonal Fe2O3. 相似文献