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1.
Divalent metal complexes of N,N′-bis(4-imidazolymethyl)etylenediamine (EMI) have been studied using potentiometric and spectroscopic
techniques (UV-Vis and NMR methods) in aqueous 0.1 mol⋅L −1 KCl supporting electrolyte at 25 °C. Final models and overall stability constants for the complexes of Ca(II), Cd(II), Co(II),
Cu(II), Mg(II), Mn(II), Ni(II), Pb(II) and Zn(II) have been established by potentiometry for all M(II)–EMI systems, except
for Co(II)–EMI. The data revealed that EMI forms ML complexes with all M(II)–EMI systems, which is the dominant species over
a wide range of pH except for the Ca(II)–EMI and Mg(II)–EMI systems. Formation of the MnHL complex was also found for Mn(II)–EMI
solutions. In addition, the UV-Vis and 1H NMR results allowed us establish the coordination modes for the metal complexes between EMI with Cd(II), Cu(II), Ni(II)
and Zn(II). 相似文献
2.
Formation equilibria of cobalt(II) complexes of 2-(aminomethyl)-benzimidazole (AMBI) and the ternary complexes Co(AMBI)L (L = aliphatic or aromatic dicarboxylic acids) were investigated in aqueous solutions at 25?°C and 0.1 mol?dm ?3 ionic strength. Stoichiometry and stability constants are reported for the complexes formed. The speciation of the complexes was resolved. Values of $\log_{10}\ (K_{\mathrm{Co(AMBI)L}}^{\mathrm{Co(AMBI)}})$ and Δlog? 10 K are calculated and discussed. The effect of chelate ring size of the dicarboxylic acid complexes on their stability constants was examined. The effect of temperature on the dissociation constant of AMBI, CBDCA, and the formation constant of Co(AMBI) and Co(AMBI)-CBDCA complexes was studied and the thermodynamic parameters were calculated. Formation of the metal complexes has been found to be spontaneous, exothermic and entropically favorable. The solid complexes of [Co(AMBI)L] (L = oxalic acid, 1,1-cyclobutanedicarboxylic acid (CBDCAH 2) and malonic acid) have been synthesized and characterized by elemental analysis, infrared, spectra, magnetic and conductance measurements. Electronic spectra and μ eff values suggest a tetrahedral geometry for Co(II)-complexes. The isolated metal chelates have been screened for their antibacterial activities and the complexes show a significant antibacterial activity against Pseudomonas fluorescence (Gram ?ve) and Bacillus subtilis (Gram +ve). The activity increases at higher concentration of the compounds. 相似文献
3.
Blood may contain high proportion of the toxic and essential metals.Blood is responsiblefor the transport of ion of such metals.The organs such as the kidney,liver and placentaare exposed to a large proportion of the metals which enter the blood and may b… 相似文献
4.
Co(II) and Cu(II) complexes and metal-free t-butylphenyl peripherally substituted porphyrazine (Pz) have been screened for in vitro antifungal ( Aspergillus niger) and antioxidant (free radical scavenging, superoxide radical scavenging, and reducing power) activities. The results were compared with synthetic antioxidants, e.g., butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), trolox, or α-tocopherol. The free radical scavenging activity of H 2Pz was higher than the CuPz complex. However, CuPz complex showed higher superoxide radical scavenging activity than BHA, BHT, and trolox while H 2Pz and CoPz showed weaker activity than BHA, BHT, and trolox. The reducing power of all complexes was similar to that of BHT and α-tocopherol on a per molar basis. The ligand and complexes have antifungal activity against A. niger. The compounds have significant superoxide radical scavenging activity against various antioxidant systems in vitro. 相似文献
5.
IntroductionTheabilityofdithiocarbamate(dtc)bindingtometalshasbeenknownformanyyears .Itformschelateswithvirtu allyalltransitionmetals.1Thebidentateanionisalsowellknownasabridgebetweentwotransitionmetalcenters.2 Wa ter solubledialkyldithiocarbamatecomplexes… 相似文献
6.
Complexes of copper(II) with a number of polyphosphate and polymetaphosphate anions have been studied in aqueous solutions
by potentiometric, spectroscopic and theoretical methods. Stability constants of the complexes have been determined as well
as their coordination modes. Results of the equilibrium studies provided evidence for the formation of ML, MHL and ML(OH)
x
type complexes with the ligands studied. The length of the polyphosphate chain was found to affect the oxygen atom charge
that is reflected in the stability constants of the ML type complexes. Moreover, the stability of the complex is also influenced
by the spatial arrangement of the phosphate groups in phosphates and metaphosphates. The spectral parameters observed for
certain complexes have permitted us to deduce the inner coordination sphere of the studied complexes. 相似文献
7.
Summary The reactions of manganese(II), cobalt(II) and nickel(II) acetates (1 mole) with antipyrine-4-azo--ethylcyanoacetate (HL 1) and antipyrine-4-azo--acetylacetone (HL 2) (1 mole) produce complexes of the M(L) 2 type. K 2PdCl 4 (1 mole) reacts with HL 1 and HL 2 (1 mole) to yield complexes of the general formula PdLCl, the ligands behaving as monobasic tridentates. The electronic spectral and magnetic data show the complexes to be high-spin octahedral, whereas the palladium(II) complexes are diamagnetic square planar. The complexes were characterized by elemental analyses, conductance measurements and i.r. and electronic spectra as well as magnetic susceptibility measurements and thermal (t.g.a. and d.t.a.) analysis.Nuclear Material Authority. 相似文献
8.
Binary and ternary complexes of zinc(II) involving nitrilo-tris(methyl phosphonic acid (H 6A) and amino acids, peptides (HL), or DNA constituents have been investigated. The stoichiometry and stability constants for
the complexes formed are reported. The results show that ternary complexes are formed in a stepwise manner whereby nitrilo-tris(methylphosphonic
acid) binds to zinc(II), which is then followed by coordination of an amino acid, peptide or DNA. Zinc(II) was found to form
ZnA and ZnAH
n
complex species where n=3, 2 or 1. The stabilities of the ternary complexes are compared with the stabilities of their corresponding binary complexes.
The concentration distributions of the various complex species have been evaluated. The kinetics of the base hydrolysis of
glycine methyl ester in the presence of Zn(II)-NTP complexes was studied in aqueous solution using a pH-stat technique. The
p K
a for ionization of the coordinated water molecule is 9.14 as determined from the kinetic results, while direct potentiometric
titration of the complex [Zn(NTP)(H 2O)] gave 9.98 (±0.02). The rate constant for the intramolecular attack of coordinated hydroxide on the ester is k=(2.65×10 −4±0.003) dm 3⋅mol −1⋅s −1. 相似文献
9.
Pressure effects on the MLCT bands of the pyrazine- and 4-cyanopyridine-pentacyanoferrate(II) anions have been established. The relation of these piezochromic effects to the solvatochromism of each complex is put into the correlation between these parameters developed for other d6 ternary complexes. The conformance of piezochromic and solvatochromic efrects on MMCT bands for diiron and diruthenium mixed valence complexes to this correlation is examined. 相似文献
10.
Summary Complexes of empirical formulae [ML 2Cl 2(OH 2) 2], [CoL 2Br 2(OH 2) 2]L·4H 2O, [NiL 2Br 2(OH 2) 2]L 2·2H 2O, [ML 2(OH 2) 4]L 2(NO 3) 2 and [ML 4(OH 2) 2](ClO 4) 2·2H 2O (M = Co II, Ni II, L = 2,4-bipyridyl) were synthesized and characterized by elemental and spectral analyses. The thermal decomposition of the complexes was also investigated.Author to whom all correspondence should be directed. 相似文献
11.
Reaction of Pd(OAc) 2 with HL 1 and HL 2 (HL 1=6-iso-propyl-2,2-bipyridine; HL 2=6-neo-pentyl-2,2-bipyridine), followed by treatment with LiCl or KI, gives [PdCl(L 1)] 2, ( 1), [PdCl(L 2)] 2 ( 2), and [PdI(L 2)] 2 ( 3), respectively. The chloride bridge in complexes 1 and 2 is split by PPh 3 to give the mononuclear species PdCl(L 1)(PPh 3) ( 4) and PdCl(L 2)(PPh 3) ( 5). Spectroscopic data provide evidence for coordination of the deprotonated ligands through a nitrogen and the C (3) atom of the 6-substituted pyridine. An analogous platinum complex PtCl(L 3)(SMe 2) ( 6) (HL 3=6-tert-butyl-2,2-bipyridine) was obtained from trans-PtClMe(SMe 2) 2 and HL 3. The crystal structures of compounds 1 and 6 have been solved by X-ray diffraction analysis.Dipartimento di Chimica, Universita di Sassari, via Vienna 2, I-07100 Sassari, Italy; Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Universita di Milano, Centro CNR, I-20133 Milano, Italy; Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1127–1137, August, 1999. 相似文献
12.
Decamethyl-3,3′-bis(dipyrrolylmethene) dihydrobromide H 2L · 2HBr (H 2L is bis(3,4,7,8,9-pentamethylpyrrol-3-yl)methane), which is the simplest representative of a novel class of oligo(dipyrrolylmethenes) belonging to chromophore chelating nonmacrocyclic ligands, were examined by 1H NMR, IR, and electronic absorption spectroscopy. Complexation reactions of H 2L · 2HBr with M(AcO) 2 (M = Zn(II), Cu(II), and Co(II)) in DMF at 298.15 K were monitored by electronic absorption spectroscopy and studied by the molar ratio method. The thermodynamic constants K 0 of these reactions were estimated. The d metal ions coordinate H 2L to give the binuclear homoleptic complexes [M 2L 2]. The reactions proceed through the intermediate binuclear heteroleptic complex [M 2L(AcO) 2] detected by spectroscopic methods. The thermodynamic stabilities of [M 2L 2] and [M 2L(AcO) 2] increase when moving from Cu(II) to Zn(II) and Co(II). The probability of formation and stability of [M 2L 2] containing 3,3′-bis(dipyrrolylmethene) are substantially higher than those of analogous complexes with the 2,2′-isomer (decamethyl-2,2′-biladiene a, c). The low K 0 values for the complexation between H 2L and Cu(AcO) 2 are due to slow oxidation of the biladiene ligand into a bilatriene with participation of Cu 2+ ions. 相似文献
13.
The platinum(II) and palladium(II) complexes [Pt 6(SCH 2CH 2NH 2) 8]Cl 4 and [Pd 6(SCH 2CH 2OH) 8 Cl 4· 5H 2O with mercamine and β-mercaptoethanol, respectively, were synthesized. It was found on the basis of the comparison of IR and X-ray electron spectra of the ligands and complexes, and also of the data of X-ray diffraction analysis that the bidentate coordination of ligands through sulfur and nitrogen atoms is realized in the platinum(II) complex. In the palladium(II) complex β-mercaptoethanol is coordinated in a mixed-mode type. In both complexes sulfur atoms of the ligands occupy a bridging position. 相似文献
14.
Treatment of [MI 2(CO) 3(NCMe) 2] with two equivalents of 4,4-bipyridine (4,4-bipy) in CH 2Cl 2 at room temperature gave the MeCN displaced products, [MI 2(CO) 3(4,4-bipy- N) 2] (1) and (2). Equimolar amounts of [MI 2(CO) 3(NCMe) 2] and L (L = PPh 3, AsPh 3 or SbPh 3) react to give [MI 2(CO) 3(NCMe)L], which when reacted in situ with 4,4-bipy yield the new complexes, [MI 2(CO) 3(4,4-bipy- N)L] (3)– (8). Reaction of equimolar quantities of [WI 2(CO)(NCMe)(
2-RC 2R) 2] (R = Me or Ph) and 4,4-bipy gave the new bis(alkyne) complexes, [WI 2(CO)(4,4-bipy- N)(
2-RC 2R) 2] (9) and (10). Treatment of [MI 2(CO) 3(NCMe) 2] with two equivalents of (9) or (10) in CH 2Cl 2 at room temperature affords the bimetallic complexes, [MI 2(CO) 3{WI 2(CO)(4,4-bipy- N, N)(
2-RC 2R) 2} 2] (11)– (14). Equimolar quantities of [MI 2(CO) 3(NCMe)(PPh 3)] (prepared in situ) and (9) or (10), react to give the 4,4-bipy-bridged complexes, [MI 2(CO) 3{WI 2(CO)(4,4-bipy- N, N)(
2-RC 2R) 2}(PPh 3)] (15)– (18). All the new complexes, (1)– (18) were characterised by elemental analysis (C, H and N), i.r. and 1H-n.m.r. spectroscopy. 相似文献
15.
4,4- Bis(chloroacetyl)diphenylmethane has been prepared from ClCH 2COCl and Ph 2CH 2. 4,4-Methylene bis(phenylglyoxylohydroximoyl chloride has also been obtained. Four new substituted 4,4- bis(alkylaminoisonitrosoacetyl)diphenylmethanes (ligands) have been prepared from 4,4-methylene bis(phenylglyoxylohydroximoyl chloride) and the corresponding amines. The Ni II, Cu II and Co II complexes of these ligands were prepared and their structures were identified using AAS, i.r., 1H-n.m.r. spectral data, elemental analyses and magnetic susceptibility measurements. 相似文献
16.
Summary New potential tetradentate ligands, N-benzoyl- N-thiobenzohydrazide (H 2BTBH) and N-salicyl- N-thiobenzohydrazide (H 2SBTH) have been prepared and characterized. Their complexes with Co II, Ni II and Zn II have been prepared and characterized on the basis of elemental analyses, magnetic susceptibility measurements, and u.v.-vis., i.r. and 1H-n.m.r. spectral studies. The bonding and stereochemistries of the complexes are discussed. H 2BTBH, H 2SBTH and the complexes have been screened towards a number of bacteria. 相似文献
17.
Neutral complexes of Cu(II), Ni(II), Co(II), and Zn(II) have been synthesized from the oxamide-based ligand derived from leucine and diethyloxalate. The structural features have been deduced from their microanalytical, IR, UV/Vis, mass, 1H and 13C NMR spectral data. The Co(II) and Ni(II) chelates have octahedral geometries and the Cu(II) chelate is a square-pyramidal geometry. The non-electrolytic and monomeric nature of the complexes is shown by their magnetic susceptibility and low conductance data. The biological activities of the ligand and its metal chelates against gram-positive and negative bacteria and fungi are also reported. All the compounds are antimicrobially active and show higher activity than the free ligand. 相似文献
18.
In this study, a mononuclear CuL complex was prepared by the use of bis-N,N′-(salicylidene)-1, 3-propanediamine (LH2) and Cu2+ ion. NiCl2 and NiBr2 salt were treated with this complex in dioxanewater medium and two new complexes [(CuL)2NiCl2(H2O)2] and [(CuL)2NiBr2(H2O)2)] with Cu(II)–Ni(II)–Cu(II) nucleus structure were obtained. In addition to this bis-N,N′-(2-hydroxybenzyl)-1,3-diaminopropane (LHH2) was prepared by the reduction of LH2 with NaBH4 in MeOH medium. The treatment of this reduced complex with Cu2+ ion resulted a complex [(CuLH)2CuCl2] with a structure of Cu(II)–Cu(II)–Cu(II). The complexes prepared were characterized by the use of elemental analysis, IR spectroscopy, thermogravimetric and X-ray diffraction methods. The crystal structures of [(CuL)2NiBr2(H2O)2] (СIF file CCDC 1448402) and [(CuLH)2CuCl2] (СIF file CCDC 1448401) complexes were elucidated. It was found that halogen ions are coordinated to terminal Cu2+ ions which are in a distorted square pyramid coordination sphere. It was determined that the central Cu(II), which joins terminal square pyramidal Cu(II), was coordinated only by the phenolic oxygens of the ligand while the central Ni(II) was coordinated by two phenolic oxygens of the organic ligand and two water molecules. These complexes were investigated by XPS and it was found that the terminal and central Cu2+ ions were different in Cu(II)–Cu(II)–Cu(II) complex. Also, the thermal degradation of the CuLH complex unit was observed to exothermic in contrast to the expectations. 相似文献
19.
The zinc(II), copper(II), nickel(II), and cobalt(II) complexes of Schiff bases, obtained by the condensation of cefixime with furyl-2-carboxaldehyde, thiophene-2-carboxaldehyde, salicylaldehyde, pyrrol-2-carboxaldehyde, and 3-hydroxynaphthalene-2-carboxaldehyde, were synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, IR, and electronic spectral measurements. Analytical data and electrical conductivity measurements indicated the formation of M?:?L (1?:?2) complexes, [M(L) 2(H 2O) 2] or [M(L) 2(H 2O) 2]Cl 2 [where M?=?Zn(II), Cu(II), Ni(II), and Co(II)] in which ligands are bidentate via azomethine-N and deprotonated-O of salicyl and naphthyl, furanyl-O, thienyl-S, and deprotonated pyrrolyl-N. The magnetic moments and electronic spectral data suggest octahedral complexes. The synthesized ligands, along with their metal complexes, were screened for their antibacterial activity against different bacterial strains. The studies show the metal complexes to be more active against one or more species as compared to the uncomplexed ligands. 相似文献
20.
Palladium(II) and platinum(II) complexes of N-ethyl- N′-pyrimidin-2-ylthiourea(HL 1) and N-phenyl- N′-pyrimidin-2-ylthiourea (HL 2) have been prepared, and the complexes [M(HL)Cl 2], [Pt(L) 2], [Pd(HL 1) 2]Cl 2, and [Pd(L 2) 2] (where M = Pd II or Pt II) were characterized. The spectroscopic data are consistent with coordination of thioureas as neutral or monoanionic ligands to Pd II and Pt II through S and a pyrimidine-N. The IR spectra show shifts of CS and pyrimidine ring stretch bands to lower and higher frequencies, respectively. The 1H NMR spectra differentiate between H(4′) and H(6′) resonances and indicate downfield shifts for all protons of pyrimidine [H(4′), H(5′), and H(6′)], two resonances for two N?H protons for complexes containing the neutral ligand (HL), and only one N?H proton chemical shift for complexes containing the monoanion (L). 13C NMR chemical shifts of pyrimidine carbons are correlated with the type of bonding between Pd II or Pt II and pyrimidine-N. The magnetic susceptibilities suggest a diamagnetic planar structure for all complexes. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
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