Synthesis and characterization of iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of salicylidene-N-anilinoacetohydrazone (H2L1) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H2L2)

A novel heterometallic compound for design and study of electrical properties of silver nanoparticles-decorated lead compounds

A novel Ag-NPs decorated on hexagonal-like PbCO₃ was constructed with a novel heterometallic compound (AgPb(C₂O₄)(NO₃)) through thermal heating at 523 K.

Synthesis, antibacterial evaluation and QSAR analysis of Schiff base complexes derived from [2,2′-(ethylenedioxy)bis(ethylamine)] and aromatic aldehydes

A novel series of Schiff base complexes (1–34) were synthesized which exhibited good antibacterial activity and compound 30 was found to be the most potent antibacterial agent.

Synthesis, Structural Characterization and Biological Activity of Novel Cyclohexane-1,3-dione Ligands and Their Metal Complexes

Some new Zn(II) and Cu(II) complexes [Cu(L¹)(OAc)₂]∙H₂O, [Cu(L¹)(NO₃)H₂O]∙NO₃∙3.5H₂O, [Zn(L¹)(NO₃)₂]∙4.5H₂O, [Zn(L¹)(OAc)₂(H₂O)₂]∙3H₂O, [Cu₂(L²)(OAc)₄]∙2H₂O∙2DMF, [Cu(L²)₂]∙2NO₃∙1.5DMF∙H₂O, [Zn(L²)₂(NO₃)₂]∙DMF and [Zn₂(L²)(OAc)₄(H₂O)₄]∙5H₂O; L¹ = 2-[2-(2-methoxyphenyl)hydrazono]cyclohexane-1,3-dione and L² = 2-[2-(3-nitrophenyl)hydrazono]cyclohexane-1,3-dione were synthesized and characterized by IR, ¹H-NMR,¹³C-NMR and ultraviolet (UV-Vis.) spectroscopy, elemental analysis, magnetic susceptibility, mass spectrometry and thermogravimetry-differential thermal analysis (TGA-DTA). The synthesized ligands and their complexes were tested for antibacterial activity against Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, and Salmonella typhimurium CCM 583. Some of complexes showed medium-level antibacterial activity against the test bacteria compared with ampicillin.

Metal-ion directed synthesis of N2O2 type chelate complexes of Ni(II), Cu(II) and Zn(II): spectral, thermal and single crystal studies

A set of Ni(II), Cu(II) and Zn(II) complexes of Schiff base have been synthesized by one pot condensation reaction of 2-hydroxy-4-methoxybenzophenone with 1,3-diaminopropane in 1:2:1 molar ratio. They have been characterized by elemental analysis, conductance measurement, thermal analysis (TGA/DTA), FT-IR, (1)H-NMR, EPR spectra, ESI-MS and electronic spectral studies. In order to establish the geometry, a single crystal X-ray structure for [Ni(L)] complex was determined. It crystallizes in monoclinic system having unit cell parameters a=14.015(5)Å, b=13.391(5)Å, c=14.931(5)Å and α=90.000(5)(o), β=112.237(5)(o), γ=90.000(5)(o) with P 2(1)/c space group. No π-π stacking interaction was obtained in molecular packing diagram. A square-planar geometry has been confirmed for Ni(II) complex. Furthermore, on the basis of elemental analysis, IR, UV-visible and EPR data a square-planar geometry for Cu(II) and a distorted octahedral geometry for the Zn(II) complex has been established. In case of Zn(II) complex NO(3)(-) group was found to be coordinated in monodentate fashion. The low molar conductivity values of the complexes measured in chloroform and DMSO suggest their non-ionic nature.

Synthesis and spectral characterization of trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes with Schiff bases

Some novel trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes of the general formula [Fe(3)O(OOCR)(3)(SB)(3)L(3)] (where R=C(13)H(27), C(15)H(31) or C(17)H(35,) HSB=Schiff bases and L=Ethanol) have been synthesized by the stepwise substitutions of acetate ions from μ(3)-oxo-hexa(acetato)tri(aqua)iron(II)diiron(III), first with straight chain carboxylic acids and then with Schiff bases. The complexes were characterized by elemental analyses, molecular weight determinations and spectral (electronic, infrared, FAB mass, Mössbauer and powder XRD) studies. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bridging nature of carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Mössbauer spectroscopic studies indicated two quadrupole-split doublets due to Fe(II) and Fe(III) ions at 80, 200 and 295K, confirming the complexes are mixed-valence species. This was also supported by the observed electronic spectra of the complexes. Magnetic susceptibility measurements displayed octahedral geometry around iron in mixed-valence state and a net antiferromagnetic exchange coupling via μ-oxo atom. Trinuclear nature of the complexes was confirmed by their molecular weight determination and FAB mass spectra. A plausible structure for these complexes has been established on the basis of spectral and magnetic moment data.

Synthesis and characterization of some bi, tri and tetravalent transition metal complexes of N'-(furan-2-yl-methylene)-2-(p-tolylamino)acetohydrazide HL1 and N'-(thiophen-2-yl-methylene)-2-(p-tolylamino)acetohydrazide HL2

The tetradentate Schiff bases hydrazone ligands HL(1), HL(2) and their metal complexes have been prepared and characterized by analytical, spectral (IR, UV-vis, (1)H NMR and ESR), molar conductivity, magnetic and TGA measurements. The results show that all the metal complexes are non-electrolytes, except (2, 10 and 20) which have ionic nature. The ligands coordinate in keto-neutral form and act as bidentate or tridentate for all metal complexes, except complexes (4 and 12). The ligands react as monobasic tetradentate and tridentate for complexes (4 and 12), respectively. Octahedral/tetrahedral Co(II) and Ni(II), octahedral/square planar Cu(II), and octahedral Mn(II), Fe(III), Cr(III), Ru(III), Hf(IV) and Zr(IV)O geometries were proposed. The ESR spectra of copper complexes (12 and 14) indicate d(x2-y2) ground state with covalent bond character. The thermal decomposition and the types of crystallized water for some metal complexes were studied. The studied metal complexes are very weakly active against the tested microorganisms.

Photoluminescent nano-sized ternary and quaternary complexes of thorium(IV)

Some ternary and quaternary complexes of thorium(IV) with the general formula [Th(OOCCH3)2−n (SB) n (OOCC15H31)2] (HSB=Schiff bases and n=1 or 2) have been synthesized by the stepwise substitutions of acetate ions from thorium(IV) acetate, first with straight chain carboxylic acid and then with Schiff bases. The complexes are characterized by elemental analyses, spectral (electronic, infrared, 1H NMR, FAB mass, photoluminescence and powder XRD) and TEM studies. Conductance measurements indicated non-conducting behaviour of the complexes. Structural parameters from powder XRD data for complexes 5 and 6 which indicate poorly crystalline nano-sized triclinic particles. Electronic absorption spectra of the complexes showed π→π * and n→π * charge transfer transitions. All complexes displayed fluorescence and a correlation was sought between luminescence spectra of complexes in solution at room temperature. On the basis of physico-chemical studies, coordination number 8 was assigned for thorium(IV) in the complexes. The morphology and microstructure of the complexes were examined with transmission electron microscopy (TEM) and the selected area electron diffraction (SAED).

First raw transition metal complexes of salicylidene and 2-hydroxy-1-naphthylidene-N-cyanoacetohydrazone

Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of salicylidene-N-cyano-acetohydrazone H2L1 and 2-hydroxy-l-naphthylidene-N-cyanoacetohydrazone H2L2 have been prepared in ethanolic solution and characterized by analytical, spectral, magnetic susceptibility, molar conductivity and TGA measurements. The analytical data show that all the complexes derived from H2L1 and H2L2 are formed in molar ratios 1M:2L, except the complexes of Mn(II), Co(II) and Cu(II) acetates of H2L2 and the complexes of Mn(II), Co(II) and Ni(II) acetates and CuCl2 of H2L1 are formed in 1:1 molar ratios. The conductance data show that all metal complexes are non-electrolytes. Electronic absorption spectra and magnetic susceptibility measurements proved that the prepared complexes have octahedral configuration except [Co(HL2)OAc] which has tetrahedral structure. The ligand field parameters were calculated for the Co(II) and Ni(II) complexes and the data show that the covalent character of the metal ligand sigma-bond is low. The ESR parameters of the Cu(II) complexes at room temperature were calculated. Thermal TGA for some solid complexes are reported.