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1.
Bala S. Prabhanada O’Neil P. Braganza Mamata H. Kombrabail Zebo R. Baratova Piotr M. Solozhenkin 《Transition Metal Chemistry》1992,17(6):552-556
X-band e.p.r. spectra from mixed ligand complexes Cu(btc)-(Hy), Cu(TPA)(Hy) and Cu(Sal)(TPA), have been derived from the spectra
of suitable reaction mixtures in CHCl3 at 25° C (Sal− = salicyladehydate, TPA− = thiopicolineanilide, Hy− = 8-hydroxyquinolinate and btc− =N-benzoyl-N′N′-diethylcarbamide). A digital data acquisition instrument and a personal computer were used for this purpose. The14N hyperfine splittings observed in these complexes have shown that the observed increase in spin density on the coordinating
atoms of one ligand, at the expense of that on the other, is unlikely to be associated with the covalent bonding involving
metal d
x
2−
y
2-orbital. Covalent bonding involving metal 4s-orbital component of the unpaired electron orbital has been suggested to be
responsible for the observed changes in electron delocalization.
This work was carried out during the visit of Drs Z. R. Baratova and P. M. Solozhenkin to India in 1991. 相似文献
2.
The reaction of [M(L)]Cl2 · 2H2O (M = Ni2+ and Cu2+, L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.18,07.12]docosane) with 1,1-cyclobutanedicarboxylic acid (H2-cbdc) generates 1D and 2D hydrogen-bonded infinite chains [Ni(L)(H-cbdc−)2] (1) and [Cu(L)(H-cbdc−)2] (2). (H-cbdc− = cyclobutane-1-carboxylic acid-1-carboxylate). These complexes have been characterized by X-ray crystallography, spectroscopy,
and cyclic voltammetry. The crystal structure of 1 shows a distorted octahedral coordination geometry around the nickel(II) ion, with four secondary amines and two oxygen atoms
of the H-cbdc− ligand at the trans position. In 2, the coordination environment around the central copper(II) ion shows a Jahn–Teller distorted octahedron with four Cu–N bonds
and two long Cu–O distances. The cyclic voltammogram of the complexes undergoes two one-electron waves corresponding to MII/MIII and MII/MI processes. The electronic spectra and electrochemical behavior of the complexes are significantly affected by the nature
of the axial H-cbdc− ligand. 相似文献
3.
A novel hexadentate nitrogen donor [N6] macrocyclic ligand viz, 1,5,11,15,21,22-hexaaza-2,14-dimethyl-l4,12-diphenyltricyclo[15.3.1.I(7–11)]docosane[1,4,6,8,10(22)-11,14,16,18,20(21)]decaene
(L), has been synthesised. The Co (II), Ni (II), and Cu (II) complexes with this ligand have been prepared and subjected to
elemental analysis, molar conductance, magnetic susceptibility measurements, mass, 1H NMR (ligand), IR, electronic, and ESR spectral studies and electrochemical investigation. On the basis of molar conductance
the complexes can be formulated as [M(L)]X2 (where M = Co (II), Ni (II), Cu (II) and X = Cl− and NO3−) due to their 1: 2 electrolytic nature in DMSO. All the complexes are of the high-spin type and are six-coordinated. On the
basis of IR, electronic, and ESR spectral studies, an octahedral geometry has been assigned for the Co(II) and Ni(II) complexes,
whereas a tetragonal geometry for the Cu(II) complexes was found. Antimicrobial activity of L and its complexes as growth
inhibiting agents have been screened in vitro against two species (F. moniliformae and R. solani) of plant pathogenic fungi.
The text was submitted by the authors in English. 相似文献
4.
pH potentiometric and spectrophotometric investigations on the complex formation equilibria of CuII with iminodiacetate (ida2−) and heterocyclic N-bases, viz. imidazole and benzimidazole (B), in aqueous solution in binary and ternary systems using
different molar ratios of the reactants indicated the formation of complexes of the types, Cu(ida), Cu(ida)(OH)−, (ida)Cu(OH)Cu(ida)−, Cu(B)2+, Cu(H-1B)+, Cu(ida)(H−1B)−, (ida)Cu(B)Cu(ida) and (ida)Cu(H−1B)Cu(ida)−. Formation constants of the complexes at 25 ±1° at a fixed ionic strength,I = 0.1 mol dm−3 (NaNO3) in aqueous solution were evaluated and the complex formation equilibria were elucidated with the aid of speciation curves.
Departure of the experimental values of the reproportionation constants(ΔlogK
cu) of ternary Cu(ida)(H−1B)− complexes from the statistically expected values, despite their formation in appreciable amounts at equilibrium, were assigned
tofac(f)-mer(m) equilibria of the ida2− ligand coordinated to CuII, as the N-heterocyclic donors, (H−1B)−, coordinatetrans- to the N-(ida2−) atom in the binary Cu(ida)
f
complex to form the ternary Cu(ida)
m
(H−1B)− complexes 相似文献
5.
Crystal structure and biological activities of water-soluble nickel(II) and copper(II) complexes of a Schiff-base derived from paeonol 总被引:1,自引:0,他引:1
Water-soluble Ni(II) and Cu(II) complexes of a flexible Schiff-base ligand have been synthesized, and the Ni(II) complex was
characterized by X-ray crystallography. The interactions of the two complexes with calf thymus DNA were investigated by spectroscopic
and viscosity measurements in water. The results suggest that the two complexes bind to DNA within the groove. Antioxidant
experiments against OH• and O2−• show that these two complexes have excellent ability to scavenge O2−•, and the Cu(II) complex exhibits better activity than the Ni(II) complex. 相似文献
6.
A novel tetradentate nitrogen donor [N4] macrocyclic ligand, i.e. 3,5,13,15,21,22-hexaaza-2,6,12,16-tetramethyl-4,14-dithia-tricyclo[15.3.1.1(7–11)]docosane-1(21),2,5,7,9,11(22),12,15,17,19-decaene,
has been synthesized. Mn(II), Co(II), Ni(II) and Cu(II) complexes with this ligand have been prepared and subjected to elemental
analyses, molar conductance measurements, magnetic susceptibility measurements, mass, 1H-n.m.r. (Ligand), i.r., electronic, and e.p.r. spectral studies. On the basis of molar conductance the complexes may be formulated
as [M(L)X2] and [Ni(L)]X2 [where M = Mn(II), Co(II) and Cu(II), and X = Cl− and NO3−] due to their nonelectrolytic nature in dimethylsulphoxide (DMSO). All the complexes are of the high spin type and are six
coordinated. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry has been assigned to Mn(II)
and Co(II), square planar for Ni(II) complexes, and tetragonal for Cu(II) complexes. The antimicrobial activities of the ligand
and its complexes, as growth inhibiting agents, have been screened in vitro against several species of bacteria and plant pathogenic fungi. 相似文献
7.
A novel tetradentate nitrogen donor [N4] macrocyclic ligand, i.e. 1,3,4,8,9,11-hexaaza-2,5,10,12-tetraoxo-7,14-diphenyl-cyclotetradecane (L), has been synthesized. Mn(II), Co(II), Ni(II)
and Cu(II) complexes of this ligand have been prepared and subjected to elemental analyses, molar conductance measurements,
magnetic susceptibility measurements, mass, 1H-n.m.r. (Ligand), i.r., electronic, and e.p.r. spectral studies. On the basis of molar conductance the Mn(II), Co(II) and
Cu(II) complexes may be formulated as [M(L)X2] [where X = Cl− & NO
3
−
] due to their non-electrolytic nature in dimethylformamide (DMF). Whereas the Ni(II) complexes are 1:2 electrolytes and formulated
as [Ni(L)]X2. All the complexes are of the high spin type and are six/four coordinate. On the basis of i.r., electronic and e.p.r. spectral
studies an octahedral geometry has been assigned to Mn(II) and Co(II), square planar for Ni(II) complexes, and tetragonal
for Cu(II) complexes. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been
screened in vitro against several species of bacteria and plant pathogenic fungi. 相似文献
8.
Cobalt(II), nickel(II) and copper(II) complexes are synthesized with 1,3,7,9-tetraaza- 4,6,10,12-tetraphenyl-2,8-dithiacyclododecane,
a tetradentate ligand (L) and characterized by elemental analysis, molar conductance measurements, magnetic susceptibitity
measurements, mass, i.r., electronic and e.p.r. spectral studies. All the complexes are non-electrolytes so they may be formulated
as [M(L)X2] [where, M = Co(II), Ni(II) and Cu(II) and X = Cl− and NO
3
−
]. All the complexes are of high spin type. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry
has been assigned for Co(II) and Ni(II) complexes and tetragonal geometry for Cu(II) complexes. The antimicrobial activities
of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against two different species of bacteria and plant pathogenic fungi. 相似文献
9.
Manisha Singla Pavan Mathur Manisha Gupta M. S. Hundal 《Transition Metal Chemistry》2008,33(2):175-182
New bis-benzimidazole based diamide ligands N, N′-bis(2-methyl benzimidazolyl)-benzene-1,3-dicarboxamide [GBBA] and N-Octyl-N, N′-bis(2-methyl benzimidazolyl)-benzene- 1,3-dicarboxamide [O-GBBA] have been synthesized and utilized to prepare Cu(II) complexes
of general composition [Cu(GBBA)X
2] · nH2O and [Cu(O-GBBA)X2] · n H2O, where X is an exogenous anionic ligand (X = Cl−, NO3−, SCN−). The oxidation of electron deficient olefins has been investigated using [Cu(O-GBBA)X2] · nH2O as catalyst and TBHP as an alternate source of oxygen. The respective ketonic products have been isolated and characterized
by 1H-NMR. The complex [Cu(GBBA)(NO3)2] · 4H2O has been characterized structurally. It crystallizes in a monoclinic space group C2/c. Low temperature EPR spectra have been obtained for the complexes that shows gII > gI > 2.0024, indicating a tetragonal geometry in the solution state. The complexes display a quasi reversible redox wave due
to the Cu(II)/Cu(I) reduction process. The E1/2 values shift anodically as NO3− < SCN− < Cl−. 相似文献
10.
A novel macrocyclic tetradentate ligand 1,5,8,12-tetraaza-2,4,9,11-tetraphenyl-6,7:13,14-dibenzocyclohexadeca- 1,4,8,11-tetraene
(L) has been synthesized. Cobalt(II), nickel(II), and copper(II) complexes of this ligand have been prepared and characterized
by elemental analysis, molar conductance measurements, magnetic susceptibitity measurements, and mass, IR, electronic, and
ESR spectral studies. The molar conductance measurements correspond to a nonelectrolytic nature for all the complexes, which
can be formulated as [M(L)X2] (where M = Co(II), Ni(II), and Cu(II); X = Cl− and NO3−). On the basis of IR, electronic, and ESR spectral studies, an octahedral geometry has been assigned to the Co(II) and Ni(II)
complexes, whereas a tetragonal geometry was found for the Cu(II) complexes. The investigated compounds and uncomplexed metal
salts and the ligands were tested against bacterial species like Sarcina lutea, Escherchia coli, and Staphylococcus aureus. The metal complexes have higher activity than the free ligand and metal salts.
The text was submitted by the authors in English. 相似文献
11.
Three macrocyclic ligands and their complexes with copper(II) salts (with anions Cl−, NO
3
−
, and NCS−) were prepared and investigated using a combination of microanalytical analysis, melting point, molar conductance measurement,
magnetic susceptibility measurement, and electronic, IR and ESR spectral studies. Ligands L1, L2, and L3 having N4, N4O2, and N4S2 core, respectively, and all the donor atoms of these ligands are bonded with Cu, which is confirmed by a seven-line pattern
observed at half-field in the frozen (H2O: MeOH = 10: 1 at pH 10) solution ESR spectrum. The polycrystalline ESR data (g
∥ = 2.20–2.27, g
⊥ = 2.01–2.05, and A
∥ = 120–270) of all the complexes together with the high asymmetry geometry suggest that all complexes appear to be near the
static distortion (CuN4O2 and CuN4S2 chromophore geometry). The electronic spectra of the complexes involve two bands at the same intensity corresponding to a
cis-distorted octahedral geometry. A common structural feature of both ligand L2 and ligand L3 is that two different donor atoms at five-membered heterocyclic aromatic ring due to this N4O2 and N4S2 chromophore form stable six-membered chelate rings with metals via these two, Cu-O and Cu-S, new interactions comparatively
to the first macrocyclic ligand, which has four-membered N,N′-chelate rings. The cyclic voltammetric studies point to a two-step
electron transfer indicating the reduction of the two copper atoms to copper(I), i.e., Cu(III)Cu(II) ⇄ Cu(II)Cu(I) ⇄ Cu(I)Cu(0).
The molar conductance for the complexes corresponds to 1: 2 and is nonelectrolyte in nature. The magnetic moment (μeff) of the complexes lie in the range between 1.80–1.96 μB. Finally, these complexes were screened for their antimicrobial activity against Aspergillus-niger of fungal strains.
The text was submitted by the authors in English. 相似文献
12.
The reaction products of Cu(II) 2-chlorobenzoate and the imidazole (1), and of Cu(II) 2,6-dichlorobenzoate and the imidazole
(2) formulated as CuL’2⋅2imd⋅2H2O and CuL”2⋅2imd⋅2H2O (L’=C7H4ClO2
−, L”=C7H3Cl2O2
−, imd=imidazole), were prepared and characterized by means of spectroscopic measurements and thermochemical properties. The blue
(1) and green (2) complexes were obtained as solids with a 1:2:2 molar ratio of metal to carboxylate ligand to imidazole.
When heated at a heating rate of 10 K min−1 the hydrated complexes, (1) and (2), lose some of the crystallization water molecules and then decompose to gaseous products.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
Arno F. Stassen Eugenia Martínez Ferrero Carlos Giménez-Saiz Eugenio Coronado Jaap G. Haasnoot Jan Reedijk 《Monatshefte für Chemie / Chemical Monthly》2003,134(2):255-264
Summary. The synthesis, crystal structure and physical properties of the complex obtained from the reaction between the polyoxometalate
anion [PMo12O40]3−, copper(II) and the ligand 1-(2-chloroethyl)tetrazole (teec) are described. This compound has been synthesized as a model for designing materials containing both magnetic polyoxometalate
anions and iron(II) spin-crossover cations.
The compound, with formula [Cu(teec)5]2[Cu(teec)6][PMo12O40]2·2H2O, consists of alternating layers of polyoxometalates and cationic complexes. Both, five and six coordinated Cu(II) ions are
present, each positioned in different layers. Despite these layers having a similar width, the layer of pentacoordinated Cu(II)
ions contains twice as many cationic complexes as the layer of hexacoordinated Cu(II) ions. This unusual coexistence of complexes
with different coordination number is most likely caused by the steric hindrance induced by the bulky polyoxometalates in
the layer of pentacoordinated Cu(II) which prevents the presence of a sixth teec ligand.
Corresponding author. E-mail: haasnoot@chem.leidenuniv.nl
Received June 5, 2002; accepted June 12, 2002 相似文献
14.
R. Gup 《Russian Journal of Coordination Chemistry》2006,32(2):99-108
A new vic-dioxime, N-{4-[[(2-hydroxyphenyl)methylene]hydrazinecarbonyl]phenyl}aminoglyoxime (H3L), was prepared by the reaction of anti-chloroglyoxime with salicylaldehyde 4-aminobenzoylhydrazone. The reaction of H3L with Cu(II) salts and an appropriate simple ligand gave only homotrinuclear complexes [Cu3(HL)2X2], whereas the reaction of H3L with Ni(II) salts gave mono-and homotrinuclear complexes [Ni(H2L)2 and Ni3(HL)2X2]. Also, heterotrinuclear complexes of H3L were prepared by the reaction of Ni(H2L)2 with Cu(II) salt and an appropriate simple ligand, [NiCu2(HL)2X2], X = Cl−, NO
3
−
, SCN−, CN−, and N
3
−
. The new vic-dioxime and its complexes were identified by elemental analyses, IR, 1H NMR, UV-VIS, magnetic susceptibility, and mass spectral data. The elemental analyses and spectral data indicated that the
hydrazone side of H3L acted as monobasic tridentate and the fourth position was occupied by simple ligands, such as Cl−, NO
3
−
, SCN−, CN−, and N
3
−
.
The text was submitted by the author in English. 相似文献
15.
M. M. Degtyarik A. S. Lyakhov O. A. Ivashkevich Yu. V. Grigoriev 《Russian Journal of Coordination Chemistry》2012,38(2):77-85
The reactions of Co(II), Ni(II), and Cu(II) chlorides and bromides and their metallic powders with tetrazol-1-yl-tris(hydroxymethyl)methane
(L) afforded new complexes ML2Hal2 · mH2O(M = Co(II) or Ni(II), Hal = Cl−; M = Cu(II), Hal = Cl− or Br−, m = 0; and M = Co(II) or Ni(II), Hal = Br−, m = 2), MLnCl2 (M = Co(II) or Ni(II), n = 2 or 4; M = Cu(II), n = 2), and MLnBr2 · mH2O (M = Ni(II), n = 2, m = 2; M = Cu(II), n = 2, m = 0). The compositions and structures of the synthesized complexes were determined by elemental analysis, IR spectroscopy
(50–4000 cm−1), and X-ray diffraction analysis. The introduction of a bulky substituent into position 1 of the tetrazole cycle was shown
to exert almost no effect on the coordination mode but affected the composition and structure of the complexes. 相似文献
16.
Arno F. Stassen Eugenia Martínez Ferrero Carlos Giménez-Saiz Eugenio Coronado Jaap G. Haasnoot Jan Reedijk 《Monatshefte für Chemie / Chemical Monthly》2003,4(4):255-264
The synthesis, crystal structure and physical properties of the complex obtained from the reaction between the polyoxometalate anion [PMo12O40]3−, copper(II) and the ligand 1-(2-chloroethyl)tetrazole (teec) are described. This compound has been synthesized as a model for designing materials containing both magnetic polyoxometalate anions and iron(II) spin-crossover cations. The compound, with formula [Cu(teec)5]2[Cu(teec)6][PMo12O40]2·2H2O, consists of alternating layers of polyoxometalates and cationic complexes. Both, five and six coordinated Cu(II) ions are present, each positioned in different layers. Despite these layers having a similar width, the layer of pentacoordinated Cu(II) ions contains twice as many cationic complexes as the layer of hexacoordinated Cu(II) ions. This unusual coexistence of complexes with different coordination number is most likely caused by the steric hindrance induced by the bulky polyoxometalates in the layer of pentacoordinated Cu(II) which prevents the presence of a sixth teec ligand. 相似文献
17.
Galactose oxidase (GOase) is a fungal enzyme which is unusual among metalloenzymes in appearing to catalyse the two electron
oxidation of primary alcohols to aldehydes and H2O2. The crystal structure of the enzyme reveals that the coordination geometry of mononuclear copper(II) ion is square pyramidal,
with two histidine imidazoles, a tyrosinate, and either H2O (pH 7.0) or acetate (from buffer,pH 4-5) in the equatorial sites and a tyrosinate ligand weakly bound in the axial position. This paper summarizes the results
of our studies on the structure, spectral and redox properties of certain novel models for the active site of the inactive
form of GOase. The monophenolato Cu(II) complexes of the type [Cu(L1)X][H(L1) = 2-(bis(pyrid-2-ylmethyl)aminomethyl)-4-nitrophenol and X− = Cl−
1, NCS−
2, CH3COO−
3, ClO4
−
4] reveal a distorted square pyramidal geometry around Cu(II) with an unusual axial coordination of phenolate moiety. The coordination
geometry of 3 is reminiscent of the active site of GOase with an axial phenolate and equatorial CH3COO− ligands. All the present complexes exhibit several electronic and EPR spectral features which are also similar to the enzyme.
Further, to establish the structural and spectroscopic consequences of the coordination of two tyrosinates in GOase enzyme,
we studied the monomeric copper(II) complexes containing two phenolates and imidazole/pyridine donors as closer structural
models for GOase. N,N-dimethylethylenediamine and N,N’-dimethylethylenediamine have been used as starting materials to obtain
a variety of 2,4-disubstituted phenolate ligands. The X-ray crystal structures of the complexes [Cu(L5)(py)], (8) [H2(L5) = N,N-dimethyl-N’,N’-bis(2-hydroxy-4-nitrobenzyl) ethylenediamine, py = pyridine] and [Cu(L8)(H2O)] (11), [H2(L8) = N,N’-dimethyl-N,N’-bis(2-hydroxy-4-nitrobenzyl)ethylenediamine] reveal distorted square pyramidal geometries around Cu(II) with the axial tertiary
amine nitrogen and water coordination respectively. Interestingly, for the latter complex there are two different molecules
present in the same unit cell containing the methyl groups of the ethylenediamine fragmentcis to each other in one molecule andtrans to each other in the other. The ligand field and EPR spectra of the model complexes reveal square-based geometries even in
solution. The electrochemical and chemical means of generating novel radical species of the model complexes, analogous to
the active form of the enzyme is presently under investigation. 相似文献
18.
A novel series of complexes of the type [M(TML)X2]; where TML is a tetradentate macrocyclic ligand; M = Co(II), Ni(II), Cu(II) or Zn(II); X = Cl−, CH3COO− or NO
3
−
have been synthesized by template condensation of benzil and thiocarbohydrazide in the presence of divalent metal salts in
methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, molecular
weight determination, magnetic measurements, electronic, NMR, infrared and far infrared spectral studies. Electronic spectra
along with magnetic moments suggest the six coordinate octahedral geometry for these complexes. The low value of molar conductance
indicates them to be non-electrolytes. The biological activities of metal complexes have been tested in vitro against a number of pathogenic bacteria to assess their inhibiting potential. 相似文献
19.
Summary The formation of near square planar mixed ligand CuII complexes with diethyldithiocarbamate (dtc) as one of the ligands and 8-hydroxyquinolinate (Hy) or salicylaldehydate (Sal) as the second ligand by exchange reactions, has been detected by e.p.r. spectroscopy. The concentrations of the mixed ligand complexes in the reaction mixtures are small compared to those of the reactants. Six different tests were used to identify the m1=3/2,63Cu hyperfine transition of the near square planar complexes, based upon the relative concentrations of the different CuII species in the reaction mixture, ligand hyperfine structures, the minium linewidths observed in a temperature dependent study and the isotropic g0 estimated from the e.p.r. spectra in solution. 相似文献
20.
Magnetic, spectral, and thermal behaviour of 2-chloro-4-nitrobenzoates of Co(II), Ni(II), and Cu(II)
Some physicochemical properties of 2-chloro-4-nitrobenzoates of Co(II), Ni(II), and Cu(II) were studied. The complexes were
obtained as mono-and dihydrates with a metal ion—ligand mole ratio of 1: 2. All complexes are polycrystalline compounds. Their
colours depend on the kind of central ion: pink for Co(II) complex, green for Ni(II), and blue for Cu(II) complexes. Their
thermal decomposition was studied only in the range of 293 K–523 K because it was found that on heating in air above 523 K
2-chloro-4-nitrobenzoates decompose explosively. Hydrated complexes lose crystallization water molecules in one step. During
dehydration process no transformation of the nitro group to nitrito one took place. Their solubilities in water at 293 K are
of the orders of 10−3-10−2 mol dm−3. The magnetic moment values of 2-chloro-4-nitrobenzoates determined in the range of 76 K–303 K change from 3.48μB to 3.82μB for Co(II) complex, from 2.24μB to 2.83μB for Ni(II) 2-chloro-4-nitrobenzoate, and from 0.31μB to 1.41μB for Cu(II) complex. 2-Chloro-4-nitrobenzoates of Co(II) and Ni(II) follow the Curie—Weiss law, but the complex of Cu(II)
forms dimer. 相似文献