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1.
Ishar Singh Ahuja Shailendra Tripathi Chhote Lal Yadava 《Transition Metal Chemistry》1988,13(2):140-142
Summary Coordination compounds formed by the interaction of manganese(II), cobalt(II), nickel(II) and copper(II) chloride and bromide with 4-cyanoaniline (4-CA) have been prepared and characterized by molar conductance, magnetic susceptibilities, electronic and i.r. spectral measurements down to 200 cm–1 in the solid state. The isolated complexes are M(4-CA)2X2 except for nickel(II) bromide which is NI(4-CA)4Br2. I.r. spectra, indicate that 4-CA, though a potentially bidentate ligand, nevertheless acts only as a terminally aniline (NH2) bonded monodentate ligand in all the complexes. Tentative stereochemistries of the complexes have been suggested in the solid state. 相似文献
2.
Marián GallMartin Breza 《Polyhedron》2012,31(1):570-574
[(CoLCl)CoCl3], [(CoMeLCl)CoCl3], [(CoLBr)CoBr3], [CoLBr]+ and [CoMeLBr2] complexes, L = hexakis(2-pyridyloxy)cyclotriphosphazene, MeL = hexakis(4-methyl-2-pyridyloxy)cyclotriphosphazene, in the most stable high spin states are investigated at DFT level of theory using hybrid B3LYP functional. The exchange coupling parameter evaluated using a broken symmetry treatment increases with the ligands mass. Electron density is evaluated in terms of QTAIM (Quantum Theory of Atoms-in-Molecule) topological analysis of electron density. The bonds of central Co atoms with phosphazene nitrogens are shorter, stronger and more polar than with the aromatic pyridine nitrogens and their higher ellipticities may be explained by the π contribution from the phosphazene ring. The atomic charges of phosphazene nitrogens are ca. twice more negative than at the pyridine ones. 相似文献
3.
The metal–ligand bonds in [(ZnCl2)2L], [NiLCl]+ and two isomers of [NiLCl2] complexes with multimodal ligand L = hexakis(2-pyridyloxy)cyclotriphosphazene, cyclo-[NP(NC5H4O)2]3, are investigated at DFT level of theory using hybrid B3LYP functional. Electron density is evaluated in terms of QTAIM (quantum theory of atoms-in-molecule) topological analysis of electron density. The bonds of central transition metal atoms with phosphazene nitrogens are shorter, stronger and more polar than with the aromatic pyridine nitrogens. The atomic charges of phosphazene nitrogens are ca twice more negative than at the pyridine ones. The higher mechanical strain in the five-coordinate metal complexes than in the six-coordinate ones may be concluded. 相似文献
4.
The formation and dissociation rates of some transition metal(II) and lanthanide(III) complexes of the 1,7,13-triaza-4,10,16-trioxacyclooctadecane N',N',N'-triacetic acid (1) and 1,7,13-triaza-4,10,16-trioxacyclooctadecane-N',N',N'- trimethylacetic acid (2) have been measured by the use of stopped-flow and conventional spectrophotometry. Experimental observations were made at 25.0 +/- 0.1 degrees C and at an ionic strength of 0.10 M KCl. The complexation of Zn(2+) and Cu(2+) ions with 1 and 2 proceeds through the formation of an intermediate complex (MH(3)L(+) *) in which the metal ion is incompletely coordinated. This may then lead to a final product in the rate-determining step. Between pH 4.68 and 5.55, the diprotonated (H(2)L(-)) form is revealed to be a kinetically active species despite its low concentration. The stability constants (log K (MH (3)L (+) *)) and specific base-catalyzed rate constants (k(OH)) of intermediate complexes have been determined from the kinetic data. The dissociation reactions of 1 and 2 complexes of Co(2+), Ni(2+), Zn(2+), Ce(3+), Eu(3+) and Yb(3+) were investigated with Cu(2+) ions as a scavenger in acetate buffer. All complexes exhibit acid-independent and acid-catalyzed contributions. The buffer and Cu(2+) concentration dependence on the dissociation rate has also been investigated. The metal and ligand effects on the dissociation rate of some transition metal(II) and lanthanide(III) complexes are discussed in terms of the ionic radius of the metal ions, the side-pendant arms and the rigidity of the ligands. 相似文献
5.
Four transition metal(II) complexes with podophyllic acid hydrazide (HL) were prepared and characterized by elemental analysis,
complexometric titration, thermal analysis, conductivity, IR, and 1H NMR. The complexes have the general formula ML2 · nH2O, where M = Zn, Cu, Co, and Ni, n = 2 or 0. Anti-tumor activities of podophyllotoxin, HL, ZnL2 · 2H2O, and NiL2 were tested by both the MTT and the SRB method. The results show that the activities of the complexes against the tumor cells
tested are superior to HL and the anti-tumor activity of NiL2 is even similar to that of podophyllotoxin. 相似文献
6.
The infrared spectra (500–140 cm?1) of the complexes [M(pyridine)n(NCS)2] (n = 2, M = Mn, Co, Ni, Cu, or Zn; n = 4, M = Mn, Fe, Co, or Ni) are discussed. The v/M-pyridine and v/M-NCS bands are assigned by observing the band shifts induced by isotopic labelling of the coordinated pyridine and isothiocyanate, by comparing the spectra with those of the [M(pyridine)2Cl2] complexes and from symmetry considerations based on their known structures. The two types of metal-ligand stretching bands occur within a rather narrow frequency range and there is evidence of some vibrational coupling between these two modes. Some earlier assignments of vM-pyridine bands require revision. The spectra of the yellow [Fe(py)4(NCS)2] complex and its violet oxidation product suggest that the oxidation reaction involves the transformation of trans-[Fe(py)4(NCS)2] into cis-[Fe(py)3(NCS)3] 相似文献
7.
8.
《Vibrational Spectroscopy》2000,22(1-2):49-54
A series of Hofmann-type clathrate host molecules containing two 2-aminopyridine (2-Apy) groups attached to transition metal (II) (M) tetracyanonickelate frame, with the formula: M(2Apy)2Ni(CN)4 (where M=Mn, Co, Cu or Zn), have been synthesised for the first time. Their FT-IR spectra are reported in the 400–4000 cm−1 region. The spectral features suggest that the compounds are substantially isostructural to that of already known Hofmann type pyridine complex; M(py)2Ni(CN)4. Moreover, 2Apy pyridine molecules are found to involve coordination through the ring nitrogen. The coordination effect on the 2Apy modes was analysed. 相似文献
9.
Dursun Ali Köse Banu Öztürk Onur Şahin Orhan Büyükgüngör 《Journal of Thermal Analysis and Calorimetry》2014,115(2):1515-1524
Coumarilate–nicotinamide complexes of CoII and ZnII were synthesized and investigated by elemental analysis, magnetic susceptibility, solid state UV–Vis, direct injection probe mass spectra, FTIR spectra, thermoanalytic TG-DTG/DTA, and crystal X-ray diffraction methods. It was obtained that both complex structures contain 2 mol aqua ligands, 2 mol coumarilate (CCA?) and 2 mol nicotinamide (NA) ligands per formula unit. The CCA? and NA ligands were bonded to metal cations as monodentate through acidic oxygen and nitrogen of pyridine ring, respectively. Thermal decomposition of each complex starts with dehydration and continue removing of 1 mol NA ligand. The thermal dehydration of the complexes takes place in one or two steps. The decomposition mechanism and thermal stability of the investigated complexes are interpreted in terms of their structures. The final decomposition products are found to be metal oxides. 相似文献
10.
11.
Raman Natarajan Kulandaisamy Antonysamy Thangaraja Chinnathangavel Jeyasubramanian Kadarkaraithangam 《Transition Metal Chemistry》2003,28(1):29-36
Neutral tetradentate chelate complexes of CuII, NiII, CoII, MnII, ZnII and VOII have been prepared in EtOH using Schiff bases derived from acetoacetanilido-4-aminoantipyrine and 2-aminophenol/2-aminothiophenol. Microanalytical data, magnetic susceptibility, i.r., u.v.–vis., 1H-n.m.r. and e.s.r. spectral techniques were used to confirm the structures of the chelates. Electronic absorption and i.r. spectra of the complexes suggest a square-planar geometry around the central metal ion, except for VOII and MnII complexes which have square-pyramidal and octahedral geometry respectively. The cyclic voltammetric data for the CuII complexes in MeCN show two waves for copper(II) copper(III) and copper(II) copper(I) couples, whereas the VOII complexes in MeCN show two waves for vanadium(IV) vanadium(V) and vanadium(IV) vanadium(III) couples. The e.s.r. spectra of the CuII, VOII and MnII complexes were recorded in DMSO solution and their salient features reported. The in vitro antimicrobial activity of the investigated compounds was tested against the microorganisms such as Salmonella typhi, Staphylococcus aureus, Klebsiella pneumoniae, Bacillus subtilis, Shigella flexneri, Pseudomonas aeruginosa, Aspergillus niger and Rhizoctonia bataicola. Most of the metal chelates have higher antimicrobial activity than the free ligands. 相似文献
12.
I. B. Kovaleva N. D. Mitrofanova L. I. Martynenko V. I. Spitsyn M. G. Felin 《Russian Chemical Bulletin》1988,37(7):1294-1298
1. | Protonated, neutral (mixed), and binuclear Cu(II), Ni(II), Co(II), Zn(II), and Mn(II) iminodisuccinate complexes have been synthesized. |
2. | Based on the results of IR-spectroscopic, thermal, and other methods of analysis, various conclusions have been drawn concerning the structures of these complexes; for instance, in the case of complexes of composition H2ML·nH2O both carboxyl groups are protonated, and one of them is coordinated to the metal ion. |
13.
Xiaoyi Li Yiqun Wu Donghong Gu Fuxi Gan 《Journal of Thermal Analysis and Calorimetry》2009,98(2):387-394
Four novel metal(II) complexes, Ni(L)2, Co(L)2, Cu(L)2, and Zn(L)2 (L = 5-(2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)hydrazono)-1,3-diethyl-2-thioxo-dihydropyrimidine-4,6(1H,5H)-dione), were synthesized using the procedure of diazotization, coupling and metallization. Their structures were identified by elemental analyses, 1H NMR, ESI-MS and FT-IR spectra. The effect of different central metal(II) ions on absorption bands of the metal(II) complexes was researched. The thermal properties of the metal(II) complexes were investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC). Furthermore, the thermodynamic parameters, such as activation energy (E*), enthalpy (?H*), entropy (?S*) and free energy of the decomposition (?G*) are calculated from the TG curves applying Coats–Redfern method. The results show that the metal(II) complexes have suitable electronic absorption spectra with blue-violet light absorption at about 350–450 nm, high thermal stability with sharp thermal decomposition thresholds. 相似文献
14.
A method is proposed for calculation of the catalytic activity of the complexes of transition metals. An effective Hamiltonian describing the behavior of the reagents in the presence of the catalyst is formulated, and a catalytic activity index tan2 is introduced. The isomerization of quadricyclane to norbornadiene is considered. It is shown that the index in the case of the catalytically active low-spin complex CoTPP is two orders of magnitude larger than in the case of the catalytically inactive high-spin complex MnTPP and the analogous Fe(III)TPP and MnPc complexes.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 4, pp. 398–406, July–August, 1988. 相似文献
15.
Summary The platinum(II) carboxylates,trans-Pt(O2CR)2(py)2 and Pt(O2CR)2bpy (R=C6F5,p-HC6F4,m-HC6F4, oro-HC6F4; bpy=2,2-bipyridyl), have been prepared by reactions oftrans-Pt(OH)2(py)2 or Pt(OH)2bpy with the appropriate polyfluorobenzoic acids, whilst [Pt(py)4](O2CC6F5)2 has been obtained from reaction oftrans-PtCl2(py)2 with thallous pentafluorobenzoate in pyridine at room temperature. In boiling pyridine, the platinum(II) polyfluorobenzoates undergo either decarboxylation givingtrans-PtR2(py)2 and PtR2bpy (R= C6F5,p-HC6F4, orm-HC6F4) complexes or substitution, giving [Pt(py)4](O2CC6F4H-o)2 and [Ptbpy(py)2](O2CC6F4H-o)2. Reactions oftrans-PtX2(py)2 and PtX2bpy (X=Cl or Br) with appropriate thallous polyfluorobenzoates in boiling pyridine have yielded the complexestrans-PtR2(py)2, PtR2bpy, PtCl(R)bpy (R=C6F5,p-HC6F4, orm-HC6F4 in each case),trans-PtCl(R)(py)2 (R = C6F5 orm-HC6F4),trans-PtBr(C6F5)(py)2, and PtBr(C6F5)bpy. The complexestrans-PtR2(py)2 (R=C6F5 orp-HC6F4) have also been prepared from potassium tetrachloroplatinate(II) and the appropriate thallous polyfluorobenzoate in boiling py, andtrans-Pt(C6F5)2(py)2 has been similarly obtained fromcis-PtCl2(py)2 and C6F5CO2Tl. Significant decarboxylation was not observed on reaction oftrans-PtCl2(py)2 or PtCl2bpy with thallous 2,3,4,5-tetrafluorobenzoate.Part II, ref. 4;Preliminary communication, ref. 3; 相似文献
16.
New Pd(II) and Pt(II) 3,6-bis(2′-pyridyl)pyridazine (dppn) mononuclear complexes of the type M(dppn)Cl2 were prepared and characterized. From M(dppn)Cl2, the bimetallic homonuclear complexes M(dppn)MCl4 were prepared by reaction with Pd(PhCN)2Cl2 or K2PtCl4. Bimetallic heteronuclear species of the type M(dppn)M′Cl4, were prepared reacting the mononuclear complexes with the stoichiometric amount of M′Cl2 (M′ = Cu, Co, Ni). All the described reaction give product in high yield. The isolated compounds, almost completely insoluble in most organic solvents, were characterized by elemental analysis, IR, ESR, reflectance spectra, and magnetic moment measurements. On the basis of these data the geometries around the metals are discussed. 相似文献
17.
The kinetics of oxidation of malic acid by peroxomonosulphate (PMS) in the presence of Cu(II) (2.50 × 10?4–5.00 × 10?3 M), Co(II) (2.00 × 10?6–1.00 × 10?5 M) and Ni(II) (5.00 × 10?4–6.00 × 10?3 M) were studied in the pH range 4.05–5.89. The oxidation of Ni(II) malate follows simple first-order kinetics with respect to both [PMS] and [Ni(II)], while the oxidations of Cu(II) malate and Co(II) malate show autocatalysis. There is an appreciable induction period in the Cu(II) malate oxidation, while Co(II) malate oxidation follows a simple curve. The initial oxidation product for all three systems was identified as malonic semialdehyde. Alcohol quenching studies suggest that, even in the Co(II) malate-PMS system, no radical intermediates such as $ {\text{SO}}_{4}^{ - .} $ or $ {\text{OH}}{}^{.} $ are detected. The malonic semialdehyde intermediate may react with M(II) malates to give a hemiacetal, which may be more reactive. 相似文献
18.
19.
L. Pospíŝil 《Journal of Electroanalytical Chemistry》1981,123(2):323-333
Integrated pulse polarography and similar techniques have been used for study of reduction of bipyridine complexes of Co(II), Ni(II) and partially also Fe(II) in aqueous solutions. By proper choice of pulse and detection intervals, it is possible to confirm or separate the contribution of reactant adsorption. The pulse polarography of the product reoxidation shows a finite charge transfer rate in the case of tris-2,2′-bipyridine cobalt complex. 相似文献
20.
Aurora Reiss Mariana Carmen Chifiriuc Emilia Amzoiu Nicoleta Cioateră Irina Dăbuleanu Petre Rotaru 《Journal of Thermal Analysis and Calorimetry》2018,131(3):2073-2085
Complexes of Co(II), Ni(II) and Cu(II) with the Schiff base (LH) derived from ceftazidime and salicylaldehyde were synthesized. The proposed structures of the new metal complexes based on the results of elemental analyses, molar conductivity, IR, DRUV and 1H NMR spectra, effective magnetic moment and thermal analysis were discussed. The surface morphology of Schiff base and metal complexes was studied by SEM. The composition of the metal complexes was ML2, where L is the deprotonated Schiff base ligand and M = Co(II), Ni(II) and Cu(II). IR spectral data indicated the Schiff base ligand being bidentately coordinated to the metallic ions with N and O atoms from azomethine and phenolic groups. All the complexes have square-planar geometry and are nonelectrolytes. The thermal analysis recorded that TG, DTG, DTA and DSC experiments confirmed the assigned composition and gave information about the thermal stability of complexes in dynamic air atmosphere. Theoretical investigation of the molecular structure of Schiff base ligand and its complexes was studied using programs dedicated to chemical modeling and quantomolecular calculation of chemical properties. The newly synthesized complexes were tested for in vitro antibacterial activity against selected Gram-negative and Gram-positive bacterial strains, and they exhibited an antibacterial activity superior to that of the Schiff base ligand. 相似文献