共查询到20条相似文献,搜索用时 125 毫秒
1.
A. M. Ryzhakov M. S. Gruzdev D. F. Pyreu E. V. Kozlovskii R. S. Kumeev 《Russian Journal of Coordination Chemistry》2010,36(8):565-571
The formation of mixed-ligand complexes HgEdtaIm2−, HgEdtaL3−, HgEdtaHL2−, and (HgEdta)2L5− (L is histidine, lysine; Im is imidazole) was studied by calorimetry, pH-metry, and NMR spectroscopy. The thermodynamic parameters
(logK, ΔrG
0, ΔrH, Δr
S) for the reactions of complex formation at 298.15 K and ion strength of 0.5 (KNO3) were determined. The most likely coordination mode for the complexone and amino acid in the mixed complexes was identified. 相似文献
2.
R. K. Verma L. Verma A. Bhushan B. P. Verma 《Journal of Thermal Analysis and Calorimetry》2007,90(3):725-729
A series of substituted triphenylphosphane complexes of the type CdL2X2 (L= triorthotolylphosphane or trimetatolylphosphane; X=Cl−, Br− or I−) and HgL2X2 (L=triphenylphosphane or triorthotolylphosphane) was prepared fresh. The thermal decomposition was carried out in air with heating
rate programmed at 10°C min−1 and it revealed that the complexes with ortho derivative were less stable and the triphenylphosphane moiety leaves along
with halogen in the first step. All the complexes were stable up to 210°C. However, the stability order of the tetrahedral
complexes was X=Cl>Br. Values of n, E, lnA and ΔS
# have been approximated and compared. Complexes having Br have higher E
a, lnA and ΔS
# values than that having Cl. 相似文献
3.
Heterobimetallic alkoxides of Cu(II) of the types [Cu{η4-Ti2(OEt)9}Cl] (1) and [Cu{η3-Ti2(OR)9}2] [R = Pri
(2), R = Et(3)] have been prepared for the first time by the reactions of CuCl2 · xROH with KTi2(OR)9 in 1:1 and 1:2 molar ratios, respectively, in benzene medium. The chloro(nonaalkoxo dititanato)copper(II) complexes undergo
chloride replacement reactions by a variety of monodentate alkoxo (−OPri, −OEt) and chelating [Al(OPri)
4
−
, Al(OEt)
4
−
, Nb(OPri)
6
−
, Zr2(OPri)
9
−
, Sn2(OPri)
9
−
, and Sn2(OEt)
9
−
] ligands to form interesting hetero(bi-and tri-)metallic complexes. Alcoholysis (with methyl alcohol and tert-butyl alcohol) and hydrolytic [with Ba(OH)2 · 8H2O powder] reactions of a few typical compounds have also been investigated. All of these have been characterized by elemental
analyses, molecular weight determinations, spectral (i.r. and visible) and magnetic studies. On attempted volatilization under
reduced pressure these complexes liberated titanium alkoxides as a volatile component leaving nonvolatile residues. 相似文献
4.
Jonathan F. Ojo Jide Ige Grace O. Ogunlusi Olanrewaju Owoyomi Esan S. Olaseni 《Transition Metal Chemistry》2006,31(6):782-785
The kinetics of the reactions between Fe(phen)
3
2+
[phen = tris–(1,10) phenanthroline] and
Co(CN)5X3− (X = Cl, Br or I) have been investigated in aqueous acidic solutions at I = 0.1 mol dm−3 (NaCl/HCl). The reactions were carried out at a fixed acid concentration ([H+] = 0.01 mol dm−3) and the second-order rate constants for the reactions at 25 °C were within the range of (0.151–1.117) dm3 mol−1 s−1. Ion-pair constants K
ip for these reactions, taking into consideration the protonation of the cobalt complexes, were 5.19 × 104, 3.00 × 102 and 4.02 × 104 mol−1 dm−3 for X = Cl, Br and I, respectively. Activation parameters measured for these systems were as follows: ΔH* (kJ K−1 mol−1) = 94.3 ± 0.6, 97.3 ± 1.0 and 109.1 ± 0.4; ΔS* (J K−1) = 69.1 ± 1.9, 74.9 ± 3.2 and 112.3 ± 1.3; ΔG* (kJ) = 73.7 ± 0.6, 75.0 ± 1.0 and 75.7 ± 0.4; E
a
(kJ) = 96.9 ± 0.3, 99.8 ± 0.4, and 122.9 ± 0.3; A (dm3 mol−1 s−1) = (7.079 ± 0.035) × 1016, (1.413 ± 0.011) × 1017, and (9.772 ± 0.027) × 1020 for X = Cl, Br, and I respectively. An outer – sphere mechanism is proposed for all the reactions. 相似文献
5.
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
6.
Numerous published data on the structure and thermodynamics of formation of molecular complexes are analyzed. The enthalpies
of complexation (−ΔH) are related to the characteristic parameter Δr = [r
DA−a
1(r
D+r
A)], where r
DA is the donor-acceptor bond length determined by microwave spectroscopy and X-ray analysis, r
D and r
A are the tabulated values of the homopolar covalent radii of the heteroatoms that form the donor-acceptor bond, and a
1 is an empirical coefficient equal to 0.901±0.007. The relation between −ΔH and Δr values has the form −ΔH = a
2/Δr (a
2 = 21.6±1.6 kJ Å mol−1), with a mean relative error of approximation of about 15% and a correlation coefficient of 0.97. As the strength of the
complex increases, the donor-acceptor bond length approaches the sum of the heteropolar covalent radii of the atoms involved
in the bond (Δr tends to zero). At Δr ≫ 1, the strength of complexes is determined by weak van der Waals interactions between the complex components and the −ΔH values tend to zero.
Dedicated to the memory of E. N. Guryanova (1911–2004), a prominent scientist who formulated the basic principles elaborated
by her disciples in this review.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1869–1878, October, 2007. 相似文献
7.
Ding-Wa Zhang Zheng-Yin Yang Shi-Ping Zhang Ru-Dong Yang 《Transition Metal Chemistry》2006,31(3):333-336
A novel ligand (H2L), diethylenetriamine-N,N′,N′′-triacetylisoniazide N,N′′-bisacetic acid, and its four non-ion transition metal complexes,
ML · nH2O (M = Mn, n = 4; M = Co, Ni, n = 2; M = Cu, n = 1), have been synthesized and characterized on the basis of elemental analysis, molar conductivity, 1H-NMR, FAB-MS, TG-DTA analysis and IR spectrum. In addition, relaxivity (R1) of the complexes was determined, the relaxivity of MnL, CoL, NiL, CuL as well as Gd(DTPA)2− used as a control are 6.94, 2.79, 2.52, 1.59 and 4.34 l mmol−1 s−1, respectively. The relaxivity of MnL is larger than that of Gd(DTPA)2−. The results show that the complex of MnL may be a potential MRI contrast agent. 相似文献
8.
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
9.
A. I. Lytkin N. V. Chernyavskaya V. E. Litvinenko 《Russian Journal of Coordination Chemistry》2011,37(12):893-896
The enthalpies of complexation between N,N-bis(carboxymethyl)aspartic acid (H4Y) and the Pb2+ ion at 298.15 K were determined from calorimetric data for a wide range of the ionic strengths (KNO3). The thermodynamic characteristics ΔH, ΔG, and ΔS, of formation of the complexes PbHY− and PbY2− were calculated for zero and fixed ionic strengths. The results obtained were interpreted. 相似文献
10.
Narayanasamy Kumaraguru Sankarlingam Arunachalam Mahadevimanglam Narayanasamy Arumugham Kannappan Santhakumar 《Transition Metal Chemistry》2006,31(2):250-255
A number of mixed ligand chromium(III)–surfactant coordination complexes, of the type cis-[Cr(en)2(A)X]2+ and cis-α-[Cr(trien)(A)X]2+ (A = Dodecyl or Cetylamine; X = F−, Cl−, Br−) were synthesized from the corresponding dihalogeno complexes by ligand substitution. These compounds form foam in aqueous
solution when shaken. The critical micelle concentration (CMC) values of these surfactant metal complexes in aqueous solution
were obtained from conductance measurements. Specific conductivity data (at 303, 308 and 313 K) served for evaluation of the
temperature-dependent critical micelle concentration (cmc) and the thermodynamics of micellization (Δ Gm0, Δ Hm0 and Δ Sm0). 相似文献
11.
Joanna Wiśniewska 《Transition Metal Chemistry》2007,32(6):811-815
The kinetics of the electron-transfer reactions between promazine (ptz) and [Co(en)2(H2O)2]3+ in CF3SO3H solution ([CoIII] = (2–6) × 10−3
m, [ptz] = 2.5 × 10−4
m, [H+] = 0.02 − 0.05 m, I = 0.1 m (H+, K+, CF3SO
3
−
), T = 288–308 K) and [Co(edta)]− in aqueous HCl ([CoIII] = (1 − 4) × 10−3
m, [ptz] = 1 × 10−4
m, [H+] = 0.1 − 0.5 m, I = 1.0 m (H+, Na+, Cl−), T = 313 − 333 K) were studied under the condition of excess CoIII using u.v.–vis. spectroscopy. The reactions produce a CoII species and a stable cationic radical. A linear dependence of the pseudo-first-order rate constant (k
obs) on [CoIII] with a non-zero intercept was established for both redox processes. The rate of reaction with the [Co(en)2(H2O)2]3+ ion was found to be independent of [H+]. In the case of the [Co(edta)]− ion, the k
obs dependence on [H+] was linear and the increasing [H+] accelerates the rate of the outer-sphere electron-transfer reaction. The activation parameters were calculated as follows:
ΔH
≠ = 105 ± 4 kJ mol−1, ΔS
≠ = 93 ± 11 J K−1mol−1 for [Co(en)2(H2O)2]3+; ΔH
≠ = 67 ± 9 kJ mol−1, ΔS
≠ = − 54 ± 28 J K−1mol−1 for [Co(edta)]−. 相似文献
12.
A new series of complexes is synthesized by template condensation of glyoxal and oxalyldihydrazide in methanolic medium in
the presence of divalent cobalt, nickel, copper, zinc and cadmium salts forming complexes of the type: [M(C8H8N8O4)X2] where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and X = Cl−1, Br−1, NO
3
−1
, OAc−1. The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic susceptibility
measurements, electronic, n.m.r., infrared and far infrared spectral studies. On the basis of these studies, a six coordinate
octahedral geometry for these complexes has been proposed. The biological activities of the metal complexes have been tested
in vitro against a number of pathogenic bacteria to assess their inhibiting potential. Most of the compounds have been found to exhibit
remarkable antibacterial activities. 相似文献
13.
Joanna Wiśniewska 《Transition Metal Chemistry》2007,32(1):107-111
The kinetics of the oxidation of promazine by trisoxalatocobaltate(III) were studied in the presence of a large excess of
the cobalt(III) in tris buffer solution using u.v.–vis spectroscopy ([CoIII] = (0.6 − 2) × 10−3
M, [ptz] = 6 × 10−5
M, pH = 6.6–7.8, I = 0.1 M (NaCl), T = 288−308 K, l = 1 cm). The reaction proceeds via two consecutive reversible steps. In the first step, the reaction leads to formation of cobalt(II) species and a stable cationic
radical. In the second step, cobalt(III) is reduced to cobalt(II) ion and a promazine radical is oxidized to the promazine
5-oxide. Linear dependences of the pseudo-first-order rate constants (k
1 and k
2) on [CoIII] with a non-zero intercept were established for both redox processes. Rates of reactions decreased with increasing concentration
of the H+ ion indicating that the promazine and its radical exist in equilibrium with their deprotonated forms, which are reactive
reducing species. The activation parameters for reactions studied were as follows: ΔH≠ = 44 ± 1 kJ mol−1, ΔS≠ = −100 ± 4 JK−1 mol−1 for the first step and ΔH≠ = 25 ± 1 kJ mol−1, ΔS≠ = −169 ± 4 J K−1 mol−1 for the second step, respectively. Mechanistic consequences of all the results are discussed. 相似文献
14.
Yue Zhang Natsumi Watanabe Yuuko Miyawaki Yutaka Mune Kenta Fujii Yasuhiro Umebayashi Shin-ichi Ishiguro 《Journal of solution chemistry》2005,34(12):1429-1443
Aprotic N,N-dimethylpropionamide (DMPA) and N,N,N′,N′-tetramethylurea (TMU) are both strong donor solvents and coordinate to metal ions through the carbonyl oxygen atom. These
solvents show a different conformational aspect in the bulk phase, i.e., DMPA exists as either a planar cis or a nonplanar staggered conformer, while TMU exists in a single planar cis conformer. It has been established that the manganese(II) ion is solvated by five molecules in both solvents. Interestingly,
although the planar cis conformer of DMPA is more favorable than the nonplanar staggered one in the bulk phase, the reverse is the case in the coordination
sphere of the metal ion, i.e., a conformational change occurs upon solvation. To reveal the thermodynamic aspect of this conformational change, the complexation
of Mn(II) with bromide ions in DMPA and TMU has been studied by titration calorimetry at 298 K. It was found that the Mn(II)
ion forms mono-, di- and tri-bromo complexes in both solvents, and their formation constants, enthalpies and entropies were
obtained. The Δ H∘1 value for MnBr+ strongly depends on the solvent, i.e., it is positive (19.4 kJ-mol−1) in DMPA and negative (−8.7 kJ-mol−1) in TMU, whereas the Δ H^∘2 and Δ H∘3 values for the stepwise formation of MnBr2 and MnBr3− are both small and negative. The enthalpy of transfer ΔtH∘ from DMPA to TMU, which is evaluated on the basis of the extrathermodynamic TATB assumption, is 25.5 kJ-mol−1 for Mn2+ and −3.6 kJ-mol−1 for MnBr+. These values indicate that the difference between the formation enthalpy of MnBr+ in the two solvents, Δ H^∘1 (DMPA) – Δ H∘1 (TMU), is mainly ascribed to the value of ΔtH∘(Mn2+). It is found that the metal ion is also five-coordinated in the monobromo complex, MnBr(DMPA)4+ . The enthalpy for the conformational change of DMPA from its planar cis to the nonplanar staggered form is evaluated to be −11 and −5.5 kJ-mol−1 for Mn(DMPA)52 + and MnBr(DMPA)4+, respectively. Note that these values are significantly smaller than the corresponding value (5.0 kJ-mol−1) in the bulk phase. We thus conclude that, although steric hindrance among solvent molecules is reduced by replacing one
DMPA of Mn(DMPA)52 + with the relatively small bromide ion, DMPA molecules are still sterically hindered in the MnBr(DMPA)4+ complex. 相似文献
15.
Copper(II) and cobalt(II) salt complexes with 2,6-dimethyl-3.5-pyridinedicarboxylic acid dihydrazide
E. Yu. Nesterova E. S. Kositsyna L. P. Tsyganok A. B. Vishnikin 《Russian Journal of Inorganic Chemistry》2012,57(3):350-357
Complexes of 2,6-dimethyl-3,5-pyridinedicarboxylic acid dihydrazide (DH) with copper(II) and cobalt(II) nitrates and sulfates
have been studied by IR and UV spectroscopy, DTA, and X-ray crystallography. The complexation results in polynuclear compounds
of the {[M(DH)(ROH)
n
]An
m
}
z
composition (M = Cu2+, Co2+; An = SO42−, NO3−; R = H, i-Pr; n = 0.5–4, m = 1.2, z ≥ 4) containing bidentate DH bridges coordinated to the metal through the carbonyl oxygen atom and the amino group nitrogen
atom of the hydrazide moiety. 相似文献
16.
Binuclear copper(II) complexes with 5-bromo-2-hydroxyacetophenone acyldihydrazones (H4L) with the composition [Cu2L·nPy] where the coordination polyhedra are linked by polymethylene chains with different lengths (from one to five units) have
been synthesized and studied. The ESR spectrum of a polycrystalline sample of a complex based on malonyldihydrazone contains
a major signal (g = 2.11) together with a weak signal corresponding to the forbidden transition (ΔM
S = 2, g = 4.18). At room temperature, ESR spectra of solutions of complexes of acyldihydrazones based on malonic, succinic, glutaric,
and adipic acids contain seven HFS lines from two equivalent copper nuclei. These lines result from weak spin-spin exchange
interaction between two unpaired electrons with the constant (36–38)·10−4 cm−1. An increase in the polymethylene chain length to five units prevents the exchange interactions, and the ESR spectrum of
a complex of the acyldihydrazone based on pimelic acid contains a signal of four HFS lines (a
Cu = 69.5·10−4 cm−1), which is common to the monomeric copper(II) compounds. In the parallel orientation, the ESR spectrum of a frozen solution of the complex of malonyldihydrazone contained
the superposition of signals due to fine and hyperfine structures with similar constants (D
∥ = 0.0074 cm−1, A
∥ = 0.0070 cm−1, g
∥ = 2.089, g
⊥ = 2.053).
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1752–1757, August, 2005. 相似文献
17.
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
18.
Five chloroanilato-bridged manganese(II) binuclear complexes, [Mn2(CA)L4](ClO4)2, where L = 4,4′-dimethyl-2,2′-bipyridine (Me2-bpy), 5-methyl-1,10-phenanthroline (Me-phen), 5-chloro-1,10-phenanthroline (Cl-phen), 5-nitro-1,10-phenanthroline (NO2-phen) and 2,9-dimethyl-1,10-phenanthroline (Me2-phen), and CA represents the dianion of chloroanilic acid, have been synthesized and characterized by elemental analyses,
molar conductivity and room temperature magnetic moment measurements, and by spectroscopy. It is proposed that these complexes
have CA-bridged structures and consist of two manganese(II) ions in a distorted-octahedral environment. The complexes [Mn2(CA)(Me2-bpy)4](ClO4)2
(1) and [Mn2(CA)(Me-phen)4](ClO4)2
(2) were characterized by variable temperature magnetic susceptibility measurements (4–300 K) and the observed data were successfully
simulated by an equation based on the spin Hamiltonian operator, Ĥ = −2JŜ
1
Ŝ
2, giving the exchange integral J = −1.98 cm−1 for (1) and J = −2.41 cm−1 for (2). This result indicates that there is a weak antiferromagnetic spin-exchange interaction between the two MnII ions within each molecule.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
19.
Guru C. Pradhan 《Transition Metal Chemistry》1992,17(5):443-445
The kinetics of the base hydrolysis ofcis-[Co(en)2(RNH2)-(SalH)]2+ (R=Me or Et; SalH=HOC6H4CO
2
−
) were investigated in aqueous ClO
4
−
in the 0.004–0.450 mol dm−3 [OH−] range, I=0.50 mol dm−3 at 30–40°C. The phenoxide species is hydrolysed via [OH−]-independent and [OH−]-dependent paths, the latter being first order in [OH−]. The high rate of alkali-independent hydrolysis of the phenoxide species is associated with high ΔH≠ and ΔS≠ values, in keeping with the SNICB mechanism involving an amido conjugate base generated by the phenoxide-assisted NH-deprotonation
of the coordinated amine. The [OH−]-dependent path also involves the conventional SN1 CB mechanism. The rate constant, k1, for the SNICB path exhibits a steric acceleration with the increasing size of the non-labile alkylamine, whereas the rate
constant, k2, for the SN1CB path shows a reverse trend.
TMC 2578 相似文献
20.
Chan-Cheng Su Tsai-Tang Hwang Orchid Y. -P. Wang Sue-Lein Wang Fen-Ling Liao 《Transition Metal Chemistry》1992,17(2):91-96
The crystal and molecular structure of [Cu(HIm)4(BF4)2]-2hmpa (HIm=imidazole; hmpa=hexamethylphosphoramide) has been determined using three-dimensional x-ray diffraction data.
The CuII ion is coordinated centrosymmetrically by four imidazole ligands forming a basal plane, mean Cu−N 2.005 Å, and by two tetrafluoroborate
anions on the z axis, mean Cu−F 2.506 Å. The four imidazole ligands are inclined at 64.6±0.5° to the CuN4 coordination plane. The discrete CuII complexes and hexamethylphosphoramide molecules are interconnectedvia hydrogen bonding between the imidazole N−H group and hmpa oxygen atom. The hmpa has a tetrahedral configuration around P
with P=O 1.489 Å and mean P−N 1.629 Å. The deconvoluted d-d absorptions of the title compound yield an orbital sequence: dx
2−y2>dz
2>dxy>dyz=dxz. The properties of the Cu-imidazole bonds are discussed with reference to the electronic structures of the chromophores of
tetrakis(imidazole)copper(II) complexes having effective local symmetriesD
4h
andD
2h
. 相似文献