Synthesis, spectral, thermal, catalytic and biological studies of some transition metal complexes with unsymmetrical Schiff base ligand (original) (raw)
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Synthetic, spectroscopic and thermal studies of some complexes of unsymmetrical Schiff base ligand
Journal of thermal analysis and …, 2012
New unsymmetrical Schiff base ligand (H 2 L) is prepared via condensation of 2-hydroxy-5-methyl acetophenone, 2-hydroxy-5-chloro-3-nitro acetophenone and carbohydrazide in 1:1:1 ratio. Metal complexes of VO(IV), Cr(III), Mn(III), Fe(III), Zr(IV), MoO 2 (VI), WO 2 (VI) and UO 2 (VI) have been prepared. These complexes were characterized by elemental analysis, UV-Vis and IR spectroscopy and magnetic moment and thermogravimetric analysis. The purity of the ligand and the metal complexes is confirmed by microanalyses, while unsymmetrical nature of ligand was further corroborated by 1 H NMR. All the complexes are air stable and insoluble in water and common organic solvents but fairly soluble in DMSO. The elemental analysis shows 1:1 metal to ligand stoichiometry for all the complexes. Thermal behaviour of the complexes was studied, the complexes were found to be quite stable and their thermal decomposition was generally via partially loss of the organic moiety and ended with respective metal oxide as a final product. Comparison of the IR spectrum of ligand and its metal complexes confirm that Schiff base behave as a dibasic tetradentate ligand towards the central metal ion with an ONNO donor sequence. The dc electrical conductivity is studied and data obtained obeyed the relation r = r 0 exp(-E a /kT) over the temperature range 40-130°C. X-ray diffraction study of VO(IV) complex shows its crystalline nature with triclinic crystal system.
Synthesis and Spectral Studies of Some Transition metal Complexes
Oriental Journal Of Chemistry, 2012
Schiff bases are an important class of ligands in coordination chemistry and their complexing ability containing different donor atoms is widely reported 1,2. The chemistry of Transition metal complexes containing schiff bases continues to be of interest on account of their interesting structural features and also because of their biological importance 3,4. The coordination complexes of the schiff bases have been widely investigated due to their manifestation of novel structural features, unusual magnetic properties and relevance to biological process 5-7. The polydentate schiff bases are well known to coordinate with various metal ions to form
JOURNAL OF ADVANCES IN CHEMISTRY
A series of homo binuclear complexs of the type [M2(L/L’)(NO3)n(H2O)2], [where M=UO22+, Th4+, ZrO2+] and [(VO)2(L/L’)(SO4)(H2O)], L= 4, 17-di(o-hydroxyphenyl)-5,6,9,12,15,16-hexaaza-7,8,13,14-tetraphenyl heptadec-4, 6, 8, 12, 14, 16-hexene or L’= 10:11-benzo-4, 17-di(o-hydroxyphenyl)-5,6,9,12,15,16-hexaaza-7,8,13,14-tetraphenyl heptadec-4, 6, 8, 12, 14, 16-hexene, n=2 for UO22+, ZrO2+ n=6 for Th4+, have been synthesized in template method from ethylenediamine/orthophenylene diamine, benzil monohydrazone and salicyldehyde and characterized on the basis of elemental analysis, thermal analysis, molar conductivity, magnetic moment, electronic, infrared, 1H-NMR studies. The results indicate that the VO(IV) ion is penta co-ordinated yielding paramagnetic complexes; UO2(VI), ZrO(IV) ions are hexa co-ordinated where as Th(IV) ion is octa co-ordinated yielding diamagnetic complexes of above composition.
Polyhedron, 2006
New bulky bisðN -3; 5-Bu t 2 phenyl-R-salicyaldiminatoÞcopperðIIÞ complexes X were synthesized and characterized by analytical, spectroscopic (IR, UV/Vis, EPR), electrochemical methods, and their chemical redox reactivity were studied. X-ray structural analysis of 1 revealed that the CuN 2 O 2 coordination core forms a distorted square-planar geometry with a cis-N 2 O 2 donor set which is not expected for analogous complexes. The UV/Vis and EPR results indicate that X complexes have a tetrahedrally distorted square-planar structure in the solid state and in solution. In the chemical oxidation of X by (NH 4 ) 2 Ce(NO 3 ) 6 along with disappearance of their EPR spectra, the appearance of new Cu(II) patterns at g = 2.169-2.189 for all X and radical signals in the cases of 5 and 6 were detected. The chemical reduction of some X complexes was accompanied by the disappearance of their EPR signals. The separation in peak potentials (DE p ) for complexes X are in order 4 < 3 < 2 < 1 < 6. The electrochemical results suggested that the complex 4 has the highest electrochemical rate assuming both the Cu(II) and Cu(I) forms appear in a similar geometrical configuration, so the electron transfer does not require larger reorganization of the complex in complex 4.
Studies on metal complexes of quinazolyl Schiff bases
2004
Department of Chemistry, Kakatiya University, Warangal-506 009, India <em>Manuscript received 8 July 2003, revised /6 December 2003, accepted 11 June 2004</em> The Co<sup>II</sup> , Ni<sup>II</sup> , Cu<sup>II</sup> , Zn<sup>II</sup>, Pd<sup>II</sup> and Cd<sup>II</sup> complexes of Schiff bases derived from 3-amino-2-mercapto-quinazolin-4-(3<em>H</em>)-one and 2-hydroxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde and 2-hydroxy-1-naphthaldlehyde'have been prepared and characterised by physico-chemical data. All the three ligands behave as uninegative, bidentate towards Pd<sup>II</sup> coordinating through phenolic oxygen and azomethine nitrogen and as unincgative, tridentate towards the other metal ions with additional coordination through thioketo sulphur. The geometry and the bonding characteristics associated with the complexes have been deduced from the electronic and...
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2007
The bifunctional carbonyl compound; 4,6-diacetylresorcinol (DAR) serves as precursor for the formation of different Schiff base ligands, which are either di-or tetra-basic with two symmetrical sets of either O 2 N or N 2 O tridentate chelating sites. The condensation of 4,6-diacetylresorcinol with 3-amino-1-propanol (3-AP) or 1,3-diaminopropane (DAP), yields the corresponding hexadentate Schiff base ligands, abbreviated as H 4 L a and H 2 L b , respectively. The structures of these ligands were elucidated by elemental analyses, IR, mass, 1 H NMR and electronic spectra. Reaction of the Schiff base ligands with copper(II), nickel(II), cobalt(II), zinc(II), cadmium(II), iron(III), chromium(III), vanadyl(IV) and uranyl(VI) ions in 1:2 molar ratio afforded the corresponding transition metal complexes. A variety of binuclear complexes for the metal complexes were obtained with the ligands in its di-or tetra-deprotonated forms. The structures of the newly prepared complexes were identified by elemental analyses, infrared, electronic, mass, 1 H NMR and ESR spectra as well as magnetic susceptibility measurements and thermal gravimetric analysis (TGA). The bonding sites are the azomethine and amino nitrogen atoms, and phenolic and alcoholic oxygen atoms. The metal complexes exhibit different geometrical arrangements such as square planar, tetrahedral, square pyramid and octahedral arrangement.
Spectral Studies of the Mixed Ligand Organometallic Complexes Derived From Schiff Base
A number of dinuclear Co(II), Ni(II), Cu(II), Mn(II) and Zn(II) complexes have been isolated by reacting bis (Salicylaldehyde) 1:2-propane diamine with metal salts and phenyl/p-tolyl mercury thiocyanate under varied reaction conditions. Structures of the complexes have been assigned on the basis of elemental analysis, molecular weights, molar conductances, magnetic moments, UV-visible, Infrared and electronic spectral studies. The physicochemical data suggest that bis (Salicylaldheyde) 1:2-propane diamine behave as dibasic tetradentate (ONNO) donor and the isolated complexes have distorted octahedral geometry. M | (salpn) i.e. N,N |-1,2-propane bis (salicylidineiminato) metal(II) coordinates to transition (1,2) and non transition (3,4) metal ion. Ni(salpn) has been used as ligand in the formation of trinuclear heterometal (5,6) complexes. Here we study on a new series of trimetallic complexes prepared from M(salpn) and (RHgSCN) 2 M(NCS) 2 [M=Co(II), Ni(II), Cu(II), Zn(II), Mn(II), M | = Co(II), Ni(II), Cu(II), Zn(II), R=C 6 H 5-, P-tolyl].
Journal of The Serbian Chemical Society, 2010
Complexes of Cu(II), Ni(II), Co(II), Mn(II) and Fe(III) with an asymmetric tetradentate Schiff base ligand derived from dehydroacetic acid, 4-methyl-o-phenylenediamine and salicylic aldehyde were synthesized and characterized by elemental analysis, conductometry, magnetic susceptibility, UV-Vis, IR, 1 H-NMR spectroscopy, X-ray diffraction analysis of powdered samples and thermal analysis, and screened for antimicrobial activity. The IR spectral data suggested that the ligand behaves as a dibasic tetadentate ligand towards the central metal ion with an ONNO donor atoms sequence. From the microanalytical data, the stoichiometry of the complexes 1:1 (metal:ligand) was found. The physico-chemical data suggested square planar geometry for the Cu(II) and Ni(II) complexes and octahedral geometry for the Co(II), Mn(II) and Fe(III) complexes. The thermal behaviour (TGA/DTA) of the complexes was studied and kinetic parameters were determined by Horowitz-Metzger and Coats-Redfern methods. The powder X-ray diffraction data suggested a monoclinic crystal system for the Co(II), Mn(II) and Fe(III) complexes. The ligand and their metal complexes were screened for antibacterial activity against Staphylococcus aureus and Escherichia coli and fungicidal activity against Aspergillus niger and Trichoderma viride.
2014
Department of Chemistry, Sant Gadge Baba Amravati University, Amravati-444 602, Maharashtra, India E-mail : aswaranand@gmail.com Manuscript received online 23 July 2013, accepted 12 August 2014 The complexes of VO<sup>IV</sup>, Mn<sup>II</sup>, Fe<sup>III</sup>, Co<sup>II</sup>, Ni<sup>II</sup>, Cu<sup>II</sup>, Zn<sup>II</sup>, Cd<sup>II</sup>, MoO<sub>2</sub> <sup>V</sup>I and UO<sub>2</sub> <sup>VI</sup> with tetradentate Schiff base ligand derived from 2-hydroxy-5-chloroacetophenone and carbohydrazide have been prepared. These complexes have been characterized by elemental analysis, <strong>UV-V</strong>is and <strong>IR</strong> spectroscopy, magnetic measurements and thermal analysis. The complexes were found to be quite stable and decomposition of the complexes ended with respective metal oxide as a final produ...
Russian Journal of Coordination Chemistry, 2004
n-heptane, and 3-methoxysalicylaldehyde were obtained from Fluka and Aldrich. The metal salts [ Cu (OAc) 2 • H 2 O ] 2 , Co (OAc) 2 • 4 H 2 O , Zn (OAc) 2 • 2 H 2 O, and NiCl 2 • 6 H 2 O were obtained from Merck. All solvents were dried and purified before use. 1-Amino-5benzoyl-4-phenyl-1H-pyrimidine-2-one was prepared as described previously [11]. The Schiff base ligand was prepared by the condensation of the 1-amino-5benzoyl-4-phenyl-1H-pyrimidine-2-one (0.2910 g, 1 mmol) with the 3-methoxysalicylaldehyde (0.1520 g, 1 mmol) in butylalcohol (40 ml) achieved by boiling the mixture under reflux for 2 h. The precipitated ligand was filtered off, recrystallized from EtOH, and dried in a vacuum desiccator. The weight of the ligand (0.85 g, 2.00 mmol) was dissolved in 30 ml of chloroform, and the solution of 1.00 mmol of the metal salt (Cu (OAc) 2 • H 2 O (0.20 g), Co (OAc) 2 • 4 H 2 O (0.25 g), Zn (OAc) 2 • 2 H 2 O (0.22 g), and NiCl 2 • 6 H 2 O (0.24 g)) in 15 ml methanol was added dropwise with continuous stirring. The mixture was stirred further for 1.5-2.5 h at 80° C. The precipitated solid was then filtered off, washed with diethyl ether, followed by cold ethanol, and dried in a vacuum desiccator. Elemental analyses (C, H, N) were performed by using a Carlo Erba 1106 elemental analyzer. The IR spectra were obtained using KBr discs (4000-400 cm-1) on a Bio-Rad-Win-IR spectrophotometer. The electronic absorption spectra in the 200-900 nm range were obtained in DMF on a Unicam UV2-100 UV-Visible spectrophotometer. Magnetic measurements were car