Lanthanons(III) Complexes of Bifunctional Tridentate Schiff's Bases

A systematic study of the reactions of isopropoxides of praseodymium, neodymium and samarium with bifunctional tridentate Schiff bases (acetylacetone-O-aminophenol and benzoylacetone-O-aminophenol) in equimolar ratios resulting in the formation of products with formula M(OPrⁱ) (SB), M(SB) (SBH) and M₂(SB)3 (where SB is Schiff base anion, SBH is Schiff base and M is metal). The reactions have been found to be quite facile even at the room temperature as observed by immediate change of colour. The intensity of the colour of acetylacetone-O-aminophenol derivatives of rare earths decreased with the increasing stoichiometric ratio of the ligand i.e. from yellow to light yellow.     

Lanthanon (III) Derivatives of Monofunctional Bidentate Schiff Bases

The 1:1, 1:2 and 1:3 interactions of lanthanon (III) isopropoxide with monofunctional bidentate Schiff bases as salicylidene-o-toluidine (SOTH) and salicylidene-p-p-toluidine (SPTH) have been investigated. The resulting products Ln(OPr¹)₂(SB), Ln(OPr¹)(SB)₂ and Ln(SB)₃ (where Ln=Pr, Nd and Sm and SB^1? is the anion of the corresponding Schiff base) have been isolated in almost quantitative yields. The infrared spectra of these compounds have been recorded and plausible structures suggested.     

Organobismuth(III) Derivatives of Sterically Hindered Bifunctional Tetradentate Schiff Bases: Synthesis and Spectroscopic Characterization

The equimolar reactions of Ph 3 Bi with the bifunctional tetradentate Schiff bases proceed with cleavage of two Bi--C bond of Ph 3 Bi and result in the formation of phenylbismuth(III) derivatives PhBi[RC(NC 6 H 4 S)CH 2 (NC 6 H 4 S)CCOOCH 3 ] where R = C 6 H 5 , 4-ClC 6 H 4 ,4-BrC 6 H 4 , and 4-CH 3 C 6 H 4 . Physico-chemical, IR, and NMR ( 1 H and 13 C) spectral studies have been carried out to investigate the structural aspect of these derivatives which reveal a penta coordination around the central Bi atom.     

Iron(III) Complexes of Tetradentate SCHIFF Bases

The iron(III) complexes of the Schiff bases derived from 1,3-diaminopropane-2-ol and salicylaldehyde (SBH₂), 3-aldehydosalicylic acid (SB′H₂) and acetylacetone (SB″H₂) have been isolated in the pure state and characterized. The structures of these complexes are discussed on the basis of elemental analyses, molecular weights, conductivities and magnetic susceptibilities. The Schiff bases behave as bivalent, tetradentate ligands. Room temperature (30°C) magnetic moments observed for these chelate compounds are lower than the spinonly value for high-spin d⁵ system.     

Synthesis and Characterization of Some New Organoantimony(III) Derivatives of N,S Donor Bifunctional Tetradentate Schiff Bases

Reactions of triphenylantimony(III) with the corresponding Schiff bases in equimolar ratios yield the phenylantimony(III) derivatives, PhSb[RC(NC 6 H 4 S)CH 2 (NC 6 H 4 S)CCOOCH 3 ] (R = C 6 H 5 , 4-ClC 6 H 4 , 4-BrC 6 H 4 , and 4-CH 3 C 6 H 4 ). These derivatives have been characterized by elemental analyses, molecular weight measurements, and IR as well as NMR ( 1 H and 13 C) spectral studies which reveal a five coordination around the central antimony atom.     

Supramolecular Associates of Nickel(II) Complexes with Nitro-Substituted Tetradentate Schiff Bases

Crystal structures of N,N'-ethylenebis(3-nitrosalicylideneiminato)nickel(II) [Ni(3-NO2SalEn)] and N,N'-(2,3-dimethylbutane-2,3-diyl)bis(3-nitrosalicylideneiminato)nickel(II) [Ni(3-NO2SaltmEn)] were determined by single crystal X-ray diffraction analysis. The [Ni(3-NO2SalEn)] complex forms supramolecular associates in the crystal phase, which affects its solubility, thermogravimetric, and spectral characteristics.     

New Nickel(II) Complexes with Tetradentate Schiff Bases Containing Electron-Acceptor Substituents

Russian Journal of General Chemistry - Complexes [Ni(3-NO2SalEn)] and [Ni(3-NO2SaltmEn)] were synthesized and identified, and polymers based on them were obtained. It was found with the help of...     

Zirconium (IV), Thorium (IV) and Dioxouranium (VI) Complexes of Dibasic Tridentate Schiff Bases

Dibasic tridentate Schiff bases obtained by the condensation of O -aminobenzoic acid with salicyldehyde and its 5-chloro and 5-bromo derivatives were synthesised and used to pracipitate Zr(IV), Th(IV) and UO₂(VI) metals as complexes. The 1:1 (metal-ligand) stoichiometry of these complexes is shown by elemental analysis, gravimetric estimations and conductometric titrations while the structures of the complexes are proved by i.r. spectra and thermogravimetric analysis. The magnetic susceptibility measurements by Gouy method show, these complexes to be monormeic and diamagnetic. The molar conductance values in nitrobenzene indicate the nonelectrolytic behaviour of the complexes. The results show that the complexes of the type Zr(OH)²L.H²O, Th(OH)²L.H²O and UO²L.H²O are formed having solvent molecule in co-ordination with metal ion.     

Copper(II), Nickel(II) and Cobalt(II) Complexes of Dibasic Tridentate Schiff Bases

Complexes of Cu(II), Ni(II) and Co(II) with the Schiff bases derived from o-aminobenzoic acid with salicylaldehyde and its 5-chloro and 5-bromo derivatives have been prepared. The 1:1 (metal-ligand) stoichiometry of these complexes is shown by elemental analysis, gravimetric estimations and conductometric titrations while the structures of the complexes are proved by i.r. spectra and thermogravimetric analysis. The magnetic susceptibility and electronic spectra of Cu(II) complexes indicate the nonplanar binuclear structures while that of Ni(II) and Co(II) show their paramagnetic octahedral geometry. The molar conductance values in nitrobenzene indicate the nonelectrolytic behaviour of the complexes. The results show that the complexes of the type (Cu·L)₂, Ni·L·3H₂O and Co·L·3H₂O are formed having solvent molecule in coordination with the metal ion. The monopyridine and monoammonia adducts of Cu(II) complexes were found to be monomeric.     

Zirconium (IV), Thorium (IV) and Dioxouranium (VI) Complexes of Dibasic Tridentate Schiff Bases

Dibasic tridentate Schiff bases obtained by the condensation of O -aminobenzoic acid with salicyldehyde and its 5-chloro and 5-bromo derivatives were synthesised and used to pracipitate Zr(IV), Th(IV) and UO₂(VI) metals as complexes. The 1: 1 (metal-ligand) stoichiometry of these complexes is shown by elemental analysis, gravimetric estimations and conductometric titrations while the structures of the complexes are proved by i.r. spectra and thermogravimetric analysis. The magnetic susceptibility measurements by Gouy method show, these complexes to be monormeic and diamagnetic. The molar conductance values in nitrobenzene indicate the nonelectrolytic behaviour of the complexes. The results show that the complexes of the type Zr(OH)₃L.H₂O₂ Th(OH)₂ L.H₂O and UO₂L.H₂O are formed having solvent molecule in co-ordination with metal ion.     

Synthetic,Spectroscopic, and Biological Aspects of Triorganosilicon(IV) Complexes of Tridentate Schiff Bases

Abstract

Hexacoordinated organosilicon complexes of type R₃Si(L) (R = ethyl, butyl, phenyl; HL = ligand, obtained by the condensation of 4-aminoantipyrine with 2-hydroxyacetophenone, 2-hydroxybenzophenone, 2-hydroxybenzaldehyde, and 2-hydroxynapthaldehyde) have been synthesized and characterized by elemental analysis, molar conductance, and spectroscopic studies (IR, ¹H, ¹³C, and ²⁹Si NMR). The spectroscopic studies indicated that the ligands acted as tridentate coordinating through azomethine nitrogen, carbonyl oxygen, and oxygen of hydroxyl after deprotonation to the central silicon atom. The ligands and their organosilicon complexes have been evaluated for antimicrobial activities against fungi (Aspergillus niger and Candida albicans), and against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis), and Gram-negative bacteria (Escherichia coli). The aim of the present work is to synthesize novel eco-friendly fungicides and bactericides and to study the effect of the biological activity of ligands on the complexation with organosilicon moiety. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Syntheses,Characterization, and Antibacterial Property of Polynuclear Cobalt(III) and Copper(II) Complexes Derived from Similar Tridentate Schiff Bases

An end-on azido-bridged trinuclear cobalt(III) complex [Co₃(L¹)₂(μ_1,1-N₃)₄(N₃)₂(OMe)(MeOH)] (I) and a phenolato-bridged dinuclear copper(II) complex [Cu₂(L²)₂(NCS)₂] (II), where L¹ is the deprotonated form of 2-((2-(dimethylamino)ethylimino)methyl)-4-fluorophenol, and L² is the deprotonated form of 2-((3-(dimethylamino)propylimino)methyl)-4-fluorophenol, have been prepared and characterized by elemental analyses, IR and UV-Vis spectra, and single crystal X-ray diffraction (CIF files CCDC nos. 1023376 (I); 1023377 (II)). The Co atoms in complex I are in octahedral coordination, and the Cu atoms in complex II are in square pyramidal coordination. The antibacterial properties have been tested on some bacteria and yeast.     

Cobalt (II) Complexes with Tri- and Tetradentate Schiff Bases Derived From 2-Furyl Glyoxal and Some Amines

Coordination compounds of cobalt (II) with four new schiff bases of furyl glyoxal, 2-furyl-methyl-2′-carboxylato ketoanil (2 FMCKA), 2-furyl glyoxal ethyenediimine (2 FGED), 2-furyl giyoxal-2′-sulphonic acid anil (2 FGSAA) and 2-furyl glyoxal-2′-chloro-4-nitro anilimimine (2 FGCNA) were prepared and characterised with the help of elemental analyses, magnetic measurements, infra-red and electonic spectral data. Various ligand field parameters such as 10 Dq, B & C, F² & F⁴, f² & f⁴, h, B° etc. and transition energies ν₁;, ν₂ & ν₃, were calculated with the help of electronic spectral data. The ν(C=N) bands in the IR spectra of all the ligands are lowered in complexation indicating nitrogen coordination of the ligands. All these studies indicate that cobalt(II) ion is in a distorted octahedral environment.     

三齿配体杂环五配位有机锡化合物的合成与生物活性

邻氨基苯酚与邻羟基芳香醛(酮)反应,合成了4个三齿Schiff碱配体(2a,2d,2g和2j),2分别与二苄基二氯化锡,二苯基二氯化锡,二正丁基二氯化锡反应合成了12个未见文献报道的三齿配体杂环五配位有机锡配合物(3a~3l),其结构经1HNMR,IR和元素分析确证。体外抗菌和抗癌活性测试结果表明,3b,3c,3f,3i和3k具有较强的抑菌活性;3c和3l具有较好的抗癌活性。     

Spectroscopic Characterization of Some Tetradentate Schiff Bases and Their Complexes with Nickel,Copper and Zinc

Three ligands have been formed by the 1:2 molar condensation of o‐phenylenediamine with salicyldhyde, 2‐hydroxy‐1‐naphthaldhyde or o‐hydroxyacetophenone. The potentially tetradentate ligands are N,N′‐bis(salicyldhyde)‐o‐phenylenediamine(SalophH₂), N,N′‐bis(2‐hydroxy‐1‐naphthaldhyde)‐o‐phenylenediamine (NophH₂) and N,N′‐bis(o‐hydroxyacetophenone)‐o‐phenylenediamine (AophH₂), respectively. These ligands form complexes (1:1 molar ratio) with nickel, copper and zinc ions. The complexes have been characterized by IR, ¹HNMR, MS, uv/vis spectra in addition to elemental analysis. The spectral data of the ligands and their complexes with nickel, copper and zinc are discussed in connection with the structural changes which occur due to complexation.     

Schiff Base Complexes of Rhodium(I) with Tridentate N-Methyl-S-methyldithiocarbazate Ligands

Schiff bases derived from the condensation of β-diketones with N-methyl-S-methyldithiocarbazates yield cis dicarbonyl complexes Rh(CO)₂ (Schiff) on reaction with [Rh(μ-Cl)(CO)₂]₂. Those derived from aromatic aldehydes form trans dicarbonyl complexes. These complexes with excess of triphenylphosphine give only Rh(CO)(PPh₃)(Schiff). cis-1,5-cyclooctadiene (COD) reacts with cis dicarbonyl complexes to yield the carbonyl-free product Rh(COD)(Schiff); similar reactions have not been observed in the case of trans-dicarbonyl complexes. Oxidative addition of bromine to these complexes yields dibromo derivative in which the Schiff base acts as bidentate chelate. Rh(PPh₃)₂(Schiff) complexes have been obtained from the reaction of above Schiff bases with Rh(PPh₃)₃Cl. The structures of these new complexes have been determined based on IR and ¹H NMR spectra.     

Synthesis,Crystal Structures,and Antibacterial Activity of Manganese(III) Complexes with Schiff Bases

Russian Journal of Coordination Chemistry - Two new manganese(III) complexes, [MnL1(EtOH)(Acac)] (I) and [MnL2(DMF)(Esal)] · H2O (II), where L1 and L2 are the dianionic form of...     

Tetradentate asymmetric Schiff bases and their Ni(II) and Fe(III) complexes

Three asymmetric Schiff-base tetradentate diimines H₂L¹, H₂L², and H₂L³ [(2-OH)C₆H₄N=CHC₆H₄2-N=CHC₆H₃(2-OH)(5-X), X?=?H, CH₃, Cl respectively] have been synthesized by a two step process. The reaction of 2-hydroxy aniline with 2-nitro-benzaldehyde in EtOH gave the starting Schiff base, 2-hydroxy-N-(2-nitrobenzylidene)aniline (SB-NO₂), which was reduced into the amino derivative (SB-NH₂) in solution. Reacting SB-NH₂ with 2-hydroxybenzaldehyde, 2-hydroxy-5-methylbenzaldehyde and 2-hydroxy-5-chlorobenzaldehyde gave the three new ligands H₂L¹, H₂L², and H₂L³ respectively. Their dimeric, binuclear metal complexes with Ni(II) and Fe(III) have also been synthesized. The ligands and their complexes were characterized by elemental analyses, LC–MS, IR, electronic, ¹H and ¹³C-NMR spectra, TGA, conductivity and magnetic measurements. All of the spectroscopic, analytical and other data indicate octahedral geometry M₂L₂(H₂O)X₂ (M: Ni,Co;X: Cl or H₂O), except for NiL² which is monomeric. Antimicrobial activities of the ligands and the complexes were evaluated against five bacteria. While the ligands and the Ni complexes are inactive towards Pseudomonas aeruginosa and Staphylococcus aureus, Fe complexes are active; only Fe complexes are inactive against Escherichia coli. All of the compounds have antimicrobial activities against Bacillus subtilis, and Yersinia enterecolitica.     

Designing,Structural Elucidation and Comparison of the Cleavage Ability of Metal Complexes Containing Tetradentate Schiff Bases 1

New N₂O₂ donor type Schiff bases have been designed and synthesized by condensing acetylaceto-4-aminoantipyrine/acetoacetanilido-4-aminoantipyrine with 2-amino benzoic acid in ethanol. Solid metal complexes of the Schiff bases with Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) metal ions were synthesized and characterized by elemental analyses, magnetic susceptibility, molar conduction, FAB Mass, IR, UV-Vis., ¹H NMR, and ESR spectral studies. The data show that the complexes have a composition of the ML type. The UV-Vis., magnetic susceptibility, and ESR spectral data of the complexes suggest a square planar geometry around the central metal ion, except for VO(IV) complexes, which have square-pyramidal geometry. The redox behavior of copper and vanadyl complexes has been studied by cyclic voltammetry. The nuclease activity of the above metal complexes shows that the complexes cleave DNA through redox chemistry. In the presence of H₂O₂, all the complexes are capable of cleaving calf thymus DNA plasmids, in order to compare the cleavage efficiency of all metal complexes in the two different ligand environments. In this assay, Cu(II), Ni(II), Co(II), and Zn(II) exhibit more cleavage efficiency than other metal ions. This article was submitted by the authors in English.     

Bioactive Penta-Coordinated Diorganotin(Iv) Complexes of Pyridoxalimine Schiff Bases

Abstract

Diorganotin(IV) complexes of an extended system derived from the condensation of pyridoxal hydrochloride with 2-amino phenol (H₂L¹), 2-amino-4-methyl phenol (H₂L²), 2-amino-4-chloro phenol (H₂L³), 2-amino-4-nitro phenol (H₂L⁴), 1-amino-2-naphthol hydrochloride (H₂L⁵) have been synthesized by the reaction of dichlorodiorganotin(IV) in a 1:1 molar ratio with these ligands. Spectral studies (IR, ¹H, ¹³C, ¹¹⁹Sn NMR) along with physical data evidenced the formation of penta-coordinated species with the ligands acting as tridentate (ONO) with oxygen occupying the axial positions, and nitrogen at one of the equatorial positions. The ligands and their organotin complexes have been evaluated for antimicrobial activity against phytopathogenic fungi Candida albicans and Aspergillus niger at 25 ± 1 °C and bacteria Bacillus subtilis, Escherichia coli, and Staphylococcus aureus at 37 ± 1 °C. The activities of the ligands have been enhanced on complexation and the results indicate that they exhibit significant antimicrobial properties.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.