共查询到20条相似文献,搜索用时 15 毫秒
1.
Khan S Nami SA Siddiqi KS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,68(2):269-274
A macrocyclic ligand, bdta (where bdta=3,6,9,12,15,18-hexaaza-1,2,10,11-tetraphenyl-2,9,11,18-tetraenecyclododecane) has been prepared by cyclocondensation of benzil with diethylenetriamine which efficiently encapsulates transition as well as pseudo-transition metal ions leading to the formation of M(bdta)Cl2 type complexes [where M=Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)]. The analytical, spectroscopic and magnetic moment data suggests an octahedral geometry for all the complexes. EPR spectra of Mn(II) and Cu(II) show considerable exchange interaction in the complex. They are non-conducting in DMSO. The TGA profile of the ligand and its complexes are identical and consists of two discreet stages. The voltammogram of Cu-complex exhibits a quasi-reversible one-electron transfer wave for Cu(II)/Cu(I) couple. 相似文献
2.
Priya Budhani Sayed Aftab Iqbal Suman Malik Mamta Bhattacharya Liviu Mitu 《Journal of Saudi Chemical Society》2010,14(3):281-285
The present paper deals with the synthesis and characterization of Schiff base complexes of pyrazinamide an antitubercular drug. Metals selected for complexation are copper, silver, gold, zinc, mercury, iron and cobalt. The complexes have been suitably synthesized and isolated in pure powdered form. Analytical data agrees with the compositions M(L), M′(L)2 and M″(L)2·2H2O, respectively where M = Ag, M′ = Cu, Au, Zn and Hg and M″ = Fe and Co, ligand metal ratios were also confirmed by monovariation method and Job’s method of continuous variation. Molar conductance values suggest the non ionic nature of the complexes. The tentative structure assigned to the complexes on the basis of stoichiometry and analytical data were further supported by spectral studies viz; IR, NMR, magnetic susceptibility and electronic spectra. A preliminary attempt has also been made to compare the potencies of metal complexes with parent drug. The Cu and Ag complexes are giving encouraging results. Particle size studies further suggest that the drug molecule undergoes reduction in size on complexation. 相似文献
3.
Saad FA Buurma NJ Amoroso AJ Knight JC Kariuki BM 《Dalton transactions (Cambridge, England : 2003)》2012,41(15):4608-4617
The synthesis of a thiourea substituted derivative of tris(pyridyl-2-methyl)amine (TPA) is reported. Two of the three pyridine rings are substituted in the 6-position with benzoylthiourea groups. These thiourea groups undergo intramolecular hydrogen bonding to form six-membered rings which leaves one N-H group available to form hydrogen bonds with other molecules. This reports details how the complexation of this new ligand with transition metal ions yields complexes with differing geometries. Seven co-ordinate Mn(II) and Cd(II), six co-ordinate Ni(II) and five co-ordinate Co(II), Cu(II) and Zn(II) complexes have been isolated. 相似文献
4.
Ray K Petrenko T Wieghardt K Neese F 《Dalton transactions (Cambridge, England : 2003)》2007,(16):1552-1566
A series of transition metal complexes involving non-innocent o-dithiolene and o-phenylenediamine ligands has been characterized in detail by various spectroscopic methods like magnetic circular dichroism (MCD), absorption (abs), resonance Raman (rR), electron paramagnetic resonance (EPR), and sulfur K-edge X-ray absorption spectroscopies. A computational model for the electronic structure of the complexes is then proposed based on the density functional theory (DFT) or ab-initio methods, which can successfully account for the observed trends in the experimental spectra (MCD, rR, and abs) of the complexes. Based on these studies, the innocent vs non-innocent nature of the ligands in a given transition metal complex is found to be dependent on the position of the central metal ion in the periodic table, its effective nuclear charge in interplay with relativistic effects. 相似文献
5.
K. Kalyanasundaram 《Journal of Chemical Sciences》1992,104(6):701-712
Applications of laser flash photolysis techniques are illustrated using three specific cases among many photoprocesses involving
transition metal polypyridyl complexes (LL = bpy, phen or related ligands): dynamics of photoinduced formation of complexes
of the type M(CO)4(LL), where M = Mo0, Cr0 or W0; dynamics of photosubstitution reactions of Ru(LL)
3
2 +
and photoredox reactions of MLCT excited states of RuII(LL)
3
2+
and [ReI(CO)3(Cl)(LL)]. 相似文献
6.
Alexey N. Egorochkin Nadiya M. Khamaletdinova 《Journal of organometallic chemistry》2011,696(10):2199-2205
The literature data on substituent influence on the CS, CN, NC, NN, and NO stretching frequencies (ν) in the IR spectra and in specific cases on their respective stretching force constants (k) have been analyzed for 28 series of the transition metal complexes. The ν and k values were first established to depend not only on the inductive and resonance effects but on the polarizability of substituents as well. The contribution of the polarizability effect varies from 0 to 57% with the type of series. 相似文献
7.
《Journal of Coordination Chemistry》2012,65(22):4007-4016
A new series of macrocyclic complexes, [M(C48H32N4)X2], where M?=?Co(II),?Ni(II),?Cu(II), and Zn(II); X?=?Cl?,?NO3 ?,?CH3COO?, have been synthesized by condensation of 1,8-diaminonaphthalene and benzil, in the presence of divalent metal salts in methanolic medium. The complexes have been characterized by elemental analyses, conductance measurements, magnetic measurements, and electronic, NMR, IR, and MS spectral studies. The low value of molar conductance indicates the presence of non-electrolytes. A distorted octahedral geometry is proposed for the complexes. The metal complexes were also tested for their in vitro antibacterial activities against some bacterial strains and compared with the standard antibiotic Ciprofloxacin. Some tested complexes show good antibacterial activities against some bacterial strains. 相似文献
8.
Summary Biologically relevant azolo (triazolo and thiazolo) diazonium salts were coupled with 2,4-pentanedione. The resulting substituted 2,4-pentanedione (L1 and L2) were condensed with 1,6-diaminohexane in the presence of chloride salts of nickel(II), copper(II), platinum(II), platinum(IV) and palladium(II) or nickel(II) and copper(II) acetates. The resulting dinuclear/polynuclear complexes were characterized by elemental analyses, conductance and magnetic moments, as well as i.r., u.v.-vis., 1H n.m.r. and e.s.r. spectra. 相似文献
9.
Tawfik H. Rakha Ahmed A. El-Asmy Mohsen M. Mostafa Abd El-Ghany El-Kourshy 《Transition Metal Chemistry》1987,12(2):125-127
Summary Benzenesulphonylhydrazine (HB) reacts with bivalent metal ions either in the keto-or enol forms. The complexes have been characterized by spectral (u.v., i.r., n.m.r.,), magnetic and thermal (d.t.a., d.t.g, t.g., d.s.c.) measurements. I.r. spectra suggest that HB is monodentate coordinatingvia NH or NH2, depending on the medium of the reaction. The participation of the O=S=O group in bondingvia bridge-formation in a polymeric chain is also considered. The substitution of ethanol in the CoII complex, [(CoB2EtOH)n], by H2O, pyridine or acetonitrile was also investigated. 相似文献
10.
Marleen L. B. F. Hereygers Herman O. Desseyn Albert T. H. Lenstra Evy Manessi-Zoupa Spyros P. Perlepes 《Transition Metal Chemistry》1996,21(3):273-282
Summary Synthetic procedures are described that allow access to the new monomeric complexes [M(HA)2(H2O)2]·2H2O (M = Mn or Co), [M(HA)2(H2O)2] (M = Fe, Ni or Zn) and [Cu(HA)2], and to the polymeric compounds [MA(H2O)]
n
(M = Mn, Co, Ni or Zn) and [CuA]
n
, where H2A = N-methyl-2-thiooxamic acid. The X-ray crystal structure of [Mn(HA)2(H2O)2]·2H2O reveals a trans, cis, cis octahedral geometry around the metal ion. The singlydeprotonated ligand behaves as a bidentate chelate with ligated atoms being the neutral thioamide sulfur and one of the carboxylate oxygens. The complexes were characterized by elemental analyses, conductivity measurements, X-ray powder patterns, magnetic susceptibilities and spectroscopic (e.s.r., ligand field, i.r., far-i.r., Raman) studies. The vibrational analysis of the complexes is presented using OH/OD, NH/ND, CH3/CD3 and metal isotopic substitutions. All data are discussed in terms of the nature of bonding in conjunction with known or assigned structures. The dianion A2– acts as a bis-bidentate O,N/O,S bridging ligand yielding highly symmetrical squares planar (CuII) and octahedral (MnII, CoII, NiII and ZnII) polymeric compounds.Dedicated to the memory of Professor Andreas G. Galinos 相似文献
11.
《Journal of Coordination Chemistry》2012,65(18):3261-3271
Two new transition metal complexes of Schiff bases, [Pd2(L1)2Cl2] (1) and [Zn(L2)2] (2), [L1?=?N-(4-fluorobenzylidene)-2,6-diisopropylbenzenamine and L2?=?2,4-dibromo-6-((E)(mesitylimino)methyl)phenol], have been synthesized solvothermally and characterized by elemental analysis, IR-spectroscopy, thermogravimetric analysis, powder X-ray diffraction, UV-vis absorption spectra, and single-crystal X-ray diffraction. Complex 1 is a μ-chloro-bridged dinuclear cyclometallated Pd(II) complex, whereas 2 is mononuclear with the ZnII tetrahedrally coordinated by two L2. Both 1 and 2 display photoluminescence in the solid state at 298?K (fluorescence lifetimes τ?=?22.516?ns at 468?nm for 1, τ?=?3.697?μs at 490?nm for 2). These Schiff bases and their metal compounds have been screened for antibacterial activity against several bacteria, and the results are compared with the activity of penicillin. 相似文献
12.
《Journal of Inorganic and Nuclear Chemistry》1978,40(1):171-174
Acetone isonicotinoyl hydrazone (AINH) has been found to form complexes of the types MCl2·AINH·nEtOH and M(AINH-H)2·nH2O where M Mn(II), Fe(II), Co(II), Ni(II), Cu(II) or Zn(II) and n 0, 1 or 2. CuICl·AINH has also been prepared starting with Cu(II) chloride. All the complexes are found to be non-electrolytes in pyridine. Tentative structural conclusions are drawn for these complexes based upon electronic spectral and room-temperature magnetic measurements. IR spectral studies suggest that AINH functions as a bi- or tridentate ligand in the complexes of the former type and as a tridentate one in the latter type of complexes. The positions of the v(M-O) mode in the low frequency IR spectra of the complexes have been correlated with their overall stability constants, log K. 相似文献
13.
Summary Acetone nicotinoyl hydrazone (ANII) complexes of the types M(ANH)Cl2 · nEtOH and M(ANH-H)2 H2O (where M = MnII FeII, CoII, NiII, CuII or ZnII and n = 0,1 or 2) have been prepared and their structures studied by molar conductance, i.r. and electronic spectra, and room temperature magnetic measurements. All the complexes arc nonionic in a 0.001 M solution of formic acid. Magnetic and electronic spectral studies show that all the complexes are spin-free regular or distorted octahedra except Mn(ANH)Cl2 and Co(ANH)CI2 which are tetrahedral. The distorted octahedral geometry of Cu(ANH-H)2 · H2O has also been confirmed from its sold state e.s.r spectrum at 77 K. From i.r. spectral studies, ANH has been found to act as a tridentate ligand in all the complexes except Mn(ANH)Cl2 where it behaves as a bidentate ligand. 相似文献
14.
15.
The synthesis and structures of acyclic and macrocyclic thio-, seleno- and telluro-ether complexes of the metallic and metalloid elements of Groups 13-16 reported since 2000 are described. The diverse structures range from discrete monomers through to infinite 1-, 2- or 3-D polymers. The coordination chemistry in this area is quite different to familiar d-block chemistry and the underlying factors are explored. 相似文献
16.
Özge Dağlı Dursun Ali Köse Onur Şahin Zarife Sibel Şahin 《Journal of Thermal Analysis and Calorimetry》2017,128(3):1373-1383
The coumarilate (coum?) complexes of CoII(1), NiII(2) CuII(3) and ZnII(4) were synthesized and characterized by elemental analysis, magnetic susceptibility, solid-state UV–Vis, FTIR spectra, thermoanalytical TG–DTG/DTA and single-crystal X-ray diffraction methods. It was found that all of the complex structures have 2 mol (coum?) ligand bonded as monoanionic monodentate in the structures of 1 and 2 while they were coordinated to metal cations as monoanionic bidentate in the complexes 3 and 4. There was not any hydrate water in the metal complexes. The complexes of 1 and 2 have four moles of aqua ligand, and the other complexes have two moles. Thermal decomposition of each complex starts with dehydration, and then the decomposition of organic parts goes. The thermal dehydration of the complexes takes place in one (for the compounds of 2, 3, 4) or two (for the compound 1) steps. The decomposition mechanism and the thermal stability of the complexes under investigation were determined on the basis of their structures. Metal oxides were obtained as the final decomposition product. 相似文献
17.
El-Wahed MG Refat MS El-Megharbel SM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(4):916-922
Compounds having general formula: [M(FO)(Cl)(x)(H(2)O)(y)].zH(2)O, where (M=Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II), FO=folate anion, x=2 or 4, y=2 or 4 and z=0, 1, 2, 3, 5 or 15) were prepared. The obtained compounds were characterized by elemental analysis, infrared as well as electronic spectra, thermogravimetric analysis and the conductivity measurements. The results suggested that all folate complexes were formed by 2:1 molar ratio (metal:folic acid) as a bidentate through both of the two carboxylic groups. The molar conductance measurements proved that the folate complexes are electrolytes. The kinetic thermodynamic parameters such as: E*, DeltaH*, DeltaS* and DeltaG* were estimated from the DTG curves. The antibacterial evaluation of the folic acid and their complexes was also done against some Gram positive/negative bacteria as well as fungi. 相似文献
18.
M.S. Sujamol C.J. Athira Y. Sindhu K. Mohanan 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(1):106-112
Complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with a novel heterocyclic azo derivative, formed by coupling diazotized 2-amino-3-carbethoxy-4,5-dimethylthiophene with acetylacetone were synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, UV–vis, IR, 1H NMR and EPR spectral data. Spectral studies revealed that the ligand existed in an internally hydrogen bonded azo-enol form rather than the keto-hydrazone form and coordinated to the metal ion in a tridentate fashion. Analytical data revealed that all the complexes exhibited 1:1 metal–ligand ratio. On the basis of electronic spectral data and magnetic susceptibility measurements, suitable geometry was proposed for each complex. The nickel(II) complex has undergone facile transesterification reaction when refluxed in methanol for a long period. The ligand and the copper(II) complex were subjected to X-ray diffraction study. The electrochemical behaviour of copper(II) complex was investigated by cyclic voltammetry. The thermal behaviour of the same complex was also examined by thermogravimetry. 相似文献
19.
Two new series of copper(II), nickel(II), cobalt(II), zinc(II), iron(III), chromium(III), vanadyl(IV) and uranyl(VI) complexes
with two bifunctional tridentate Schiff base, H4L1 and H2L2 ligands have been prepared. The Schiff base, H4L1 and H2L2, ligands were synthesized by the condensation of 4,6-diacetylresorcinol with o-aminophenol or o-phenylenediamine. The ligands are either di- or tetra-basic with two symmetrical sets of either OON or NNO tridentate chelating
sites. The ligands and their metal complexes have been characterized by elemental analysis, 1H-n.m.r., FT-IR, mass, electronic, esr spectra and thermal gravimetric analysis and magnetic susceptibility. With the exception
of CoII ion with H2L2 which afforded a trinuclear complex, a variety of binuclear complexes for the rest of the metal complexes were obtained with
the ligands in its di- or tetra-deprotonated forms. The bonding sites are the azomethine and amino nitrogen atoms, and phenolic
oxygen atoms. The metal complexes exhibit different geometrical arrangements such as square planar, tetrahedral, square pyramid
and octahedral arrangement. 相似文献