Monobasic Bidentate Schiff Base Research Articles

Synthesis, spectral, electrochemical and DNA binding properties of ruthenium (III) complexes of Schiff bases containing N,O donor atoms

A new series of octahedral Ru(III) complexes of the type [Ru (Cl)2 (DMAPIMP-X) (EPh3)2]; DMAPIMP={2-[(4-N,N’-dimethylaminophenylimino)-methyl]-4-X-phenol}; X = Cl, Br or I; E = P or As) have been prepared and characterized by spectral, magnetic and cyclic voltammetric studies. The Ru (III) complexes are low spin and paramagnetic with one unpaired electron. These complexes absorb strongly in the visible region owing to the metal to ligand charge transfer (MLCT) transition. The IR spectral data reveals that the monobasic bidentate Schiff base ligands are chelated to ruthenium through the imine nitrogen and the deprotonated phenolic oxygen. The three line e.s.r spectrum of RuIII complexes with gx ≠ gy ≠ gz indicates magnetic anisotropy and an asymmetry in the electronic environment around the Ru atom. All Ru(III) complexes display the redox couple in the range – 0.826 to – 0.971 V. Further more the DNA binding experiment of the complexes were carried out by UV–Vis absorption spectral titration and the binding constant Kb = 1.2 ± 0.3 × 104 M−1 to 4.4 ± 0.3 × 104 M−1 have been found. The hyperchromism with moderate red shift of 2–4 nm, such a small change in λmax is more in keeping with groove binding, leading to small perturbations.

Syntheses, characterization, superoxide dismutase, antimicrobial, crystal structure and molecular studies of copper (II) and nickel (II) complexes with 2-((E)-(2, 4-dibromophenylimino) methyl)-4-bromophenol as Schiff base ligand

Three new copper (II) and nickel (II) complexes viz. [Cu(L)2](1a), [Cu(L)2](1b) and [Ni(L)2].DMF(2), where HL = 2-((E)-(2, 4-dibromophenylimino) methyl)-4-bromophenol, have been synthesized and characterized by using various physico-chemical and spectroscopic techniques. The crystal structures of Schiff base (HL) and their metal complexes (1a), (1b) and (2) were determined by single crystal X-ray diffraction. IR and UV–Vis spectra and magnetic susceptibility measurements agree with the observed crystal structures. The crystallographic and spectroscopic studies confirmed four coordinate environments around the metal (II) ions. The synthesized Schiff base ligand (HL) crystallizes in the orthorhombic system of the space group Pbca. Complex (1a) of HL was crystallized in the monoclinic system of the space group P21/c, a = 10.1712(9) Å, b = 10.9299(10) Å,c = 12.7684(11) Å,α = 90̊,β = 104.649(2)̊, γ = 90̊ and Z = 2 whereas complex (1b) and (2) crystallized in the triclinic system of the space group P-1, a = 11.499(5)Å, b = 11.598(5)Å, c = 12.211(5)Å, α = 98.860(5), β = 115.653(5),γ = 100.906(5) and Z = 2 for (1b), a = 9.080(6) Å, b = 9.545(8)Å, c = 9.545(8)Å, α = 101.43(4)º,β = 99.63(3)̊, γ = 117.71(2)º and Z = 1 for (2). The synthesized ligand (HL) was behaved as monobasic bidentate Schiff base ligand having N and O donor sites. The electron paramagnetic resonance spectra indicate a dx2–y2ground state (g|| > g⊥> 2.0023) for (1a) and (1b). Copper (II) complexes display X-band EPR spectra in 100% DMSO and 77 K, giving indicating dx2–y2ground state. Superoxide dismutase-like activities of HL and its complexes were investigated by nitrobluetetrazolium chloride-DMSO assay and IC50 values were evaluated. These complexes were also tested for their in vitro antimicrobial activities against two bacteria (E. coli and Salmonella typhi) and two fungi (Pencillium, Aspergillus sp.) comparing with the Schiff base. The antimicrobial results showed that the complexes were more biologically active compounds to the Schiff base (HL).

Manganese(II) and Dioxomolybdenum(VI) Complexes with Monobasic Bidentate Schiff Bases : Synthesis, Characterization and Biological Investigation

spectral studies. The magnetic moment values of the manganese(II) complexes are in the range of 5.80-6.15 B.M. suggesting a high spin state of manganese in these complexes. The spectral data are consistent with a tetrahedral geometry around Mn(II) and an octahedral geometry for Mo(VI), in which the ligands act as bidentate chelating agents, coordinated through the nitrogen and sulfur/oxygen atoms. The ligands and their metal complexes have been tested against a number of pathogenic fungi and bacteria at different concentrations and were found to possess sufficient fungicidal and bactericidal properties. Further, the complexes were also tested for their antifertility activity in male albino rats and the results were indeed positive.

Spectral and biocidal studies of manganese(II), dioxomolybdenum(VI) and oxovanadium(V) complexes with monobasic bidentate Schiff base ligands

Spectral and biocidal studies of manganese(II), dioxomolybdenum(VI) and oxovanadium(V) complexes with monobasic bidentate Schiff base ligands

Coordination chemistry of palladium(II) and platinum(II) complexes with bioactive Schiff bases: Synthetic, spectral, and biocidal aspects

The Schiff bases, 5-nitro-indol-2,3-dionehydrazinecarboxamide (HSCZ1) and 7-nitro-indol-2,3- dionehydrazinecarboxamide (HSCZ2), have been synthesized by the condensation of 5-nitro-indol-2,3-dione and 7-nitro-1H-indol-2,3-dione with semicarbazide hydrochloride, respectively. The palladium(II) and platinum( II) complexes have been prepared by mixing palladium chloride and platinum chloride in 1: 2 molar ratios with monobasic bidentate Schiff bases. The ligands and complexes of palladium and platinum have been characterized by elemental analyses, melting point determinations, conductance measurements, molecular weight determinations, and IR, 1H NMR, and UV spectral studies. These studies showed that the ligands coordinate to the metal atoms in a monobasic bidentate mode, coordinating through oxygen and nitrogen donor systems. Thus, a tetracoordinated environment around the metal atom has been proposed. Both the ligands and their complexes have been screened for their biological activity on several pathogenic fungi and bacteria and were found to possess appreciable fungicidal and bactericidal properties. Plant growth regulating activity of one of the ligands and its complexes has also been recorded on gram plant, and results have been discussed.

Synthesis and characterization of polystyrene-anchored monobasic bidentate Schiff base and its complexes with bi-, tri-, tetra- and hexavalent metal ions

A new monobasic bidentate ON donor Schiff base PS–LH2 (where PS–LH2 = polystyrene-anchored Schiff base obtained by condensation of chloromethylated polystyrene (containing 1.17 mmol of chlorine per gram of resin cross-linked with 2% divinylbenzene), 2-hydroxy-1-naphaldehyde and 4-aminosalicylic acid has been synthesized. PS–LH2 reacts with metal complexes to form polystyrene-anchored complexes: PS–LHM(CH3Coo) · DMF (where M = Cu, Zn, Cd, UO2), PS–LHZr(OH)2(CH3Coo) · 2DMF, PS–LHFeCl2 · 2DMF, PS–LHM′(CH3Coo) · 3DMF (where M′ = Mn and Ni) and PS–LHMoo2(acac), where acacH = acetylacetone. The polystyrene-anchored complexes have been characterized by elemental analysis, IR, ESR and magnetic susceptibility measurements. The per cent reaction conversion of PS–LH2 to polystyrene supported coordination compounds lies between 30–95. Shifts of the azomethine ν(C=N) and phenolic ν(C–O) stretches are indicative of ON donor behaviour of the polystyrene-anchored ligands. The complexes, PS–LHCu(CH3Coo) · DMF, PS–LHFecl2 · 2DMF, PS–LHMn(CH3Coo) · 3DMF and PS–LHNi(CH3Coo) · 3DMF are paramagnetic, while PS–LHZn(CH3Coo) · DMF, PS–LHCd(CH3COO) · DMF, PS–LHUo2(CH3Coo) · DMF, PS–LHZr(OH)2(CH3COO) · 2DMF and PS–LHMoO2(acac) are diamagnetic. The copper(II) complex exhibits a square planar structure, zinc(II) and cadmium(II) complexes have tetrahedral structures, nickel(II), manganese(II), iron(III), dioxomolybdenum(VI) and dioxouranium(VI) complexes have octahedral structure and zirconium(IV) complex is pentagonal bipyramidal.

Spectral and biocidal studies of palladium(II) and platinum(II) complexes with monobasic bidentate Schiff bases

The monobasic bidentate Schiff base complexes of palladium(II) and platinum(II) derived from 1H-indol-2,3-dione thiosemicarbazone (L1H) and 1H-indol-2,3-dione semicarbazone (L2H) have been characterized on the basis of elemental analysis, molecular weight determinations, i.r., 1H n.m.r. and u.v. spectral studies. Based on these studies a square planar environment around the metal atoms has been proposed. Antimicrobial effects of both the ligands and their complexes on different species of pathogenic fungi and bacteria have been recorded and these are found to possess significant fungicidal and bactericidal properties.

Synthesis, characterization, electro chemistry, catalytic and biological activities of ruthenium(III) complexes with bidentate N, O/S donor ligands

New hexa-coordinated ruthenium(III) complexes of the type [RuX2(EPh3)2(L)] (E=P or As; X=Cl or Br; L=monobasic bidentate Schiff base derived from the condensation of benzhydrazide with furfuraldehyde, 2-acetylfuran and 2-acetylthiophene) have been synthesized from the equimolar amounts of [RuX3(EPh3)3] or [RuBr3(PPh3)2(MeOH)] and Schiff bases in benzene. The new complexes have been characterized by analytical, spectral (IR, electronic and EPR), magnetic moment, and cyclic voltammetry. An octahedral structure has been tentatively proposed. All the complexes have exhibited catalytic activity for the oxidation of benzyl alcohol, cyclohexanol and cinnamylalcohol in the presence of N-methylmorpholine-N-oxide as co-oxidant. All the new complexes were found to be active against the bacteria such as E. coli, Pseudomonas, Salmonella typhi and Staphylococcus aureus. The activity was compared with standard Streptomycin.

Syntheses, magnetic and spectral studies on polystyrene supported coordination compounds of bidentate and tetradentate Schiff bases

The reaction of aminomethylated polystyrene (PSCH2-NH2) and 2-hydroxyacetanilide in DMF results in the formation of polystyrene-anchored monobasic bidentate Schiff base, PSCH2-LH (I). On the other hand, the reaction of chloromethylated polystyrene (PSCH2-Cl), 3-formylsalicylic acid, ethylenediamine and acetylacetone in DMF in presence of ethyl acetate (EA) and triethylamine (TEA) produces another polystyrene-anchored dibasic tetradentate Schiff base, PSCH2-L′H2 (II). BothI andII react with a number of di-, tri-and hexavalent metal ions like Co, Ni, Cu, Zn and Cd to form polystyreneanchored coordination compounds, and these have been characterized and discussed.

Catalytic and biological activities of Ru(III) mixed ligand complexes containing N,O donor of 2-hydroxy-1-naphthylideneimines

A series of stable low spin Ru(III) complexes of the type [RuX 2(EPh 3) 2(L)] (where E = P or As; X = Cl or Br; L = mono basic bidentate Schiff bases) have been synthesized and were characterized by analytical, spectral and electrochemical data. A distorted octahedral geometry has been proposed for all the complexes. These complexes catalyze oxidation of primary alcohols and secondary alcohol with high yields in the presence of N-methylmorpholine- N-oxide (NMO). The ruthenium(III) Schiff base complexes show growth inhibitory activity against the bacteria Staphylococcus aureus ( 209p) and E. coli ESS ( 2231).

Synthesis, spectra, dioxygen affinity and antifungal activity of Ru(III) Schiff base complexes

The reaction of ruthenium(III) complexes, [RuX 3(EPh 3) 3] (E=As, X=Cl or Br; E=P, X=Cl) and [RuBr 3(PPh 3) 2(CH 3OH)] with bidendate Schiff base ligands derived by condensing salicylaldehyde with methylamine (Hsalmet), cyclohexylamine (Hsalchx), 2-aminopyridine (Hsalampy) have been carried out. The complexes were characterized by analytical and spectral studies (IR, electronic and EPR) and are formulated as [RuX(EPh 3)(LL′) 2] (where LL′=monobasic bidentate Schiff base ligand; E=P or As, X=Cl or Br). An octahedral geometry has been tentatively proposed for the new complexes. Dioxygen affinity of some of the Ru(III) Schiff base complexes was studied by cyclic voltammetry. The representative Schiff bases and their complexes were tested in vitro to evaluate their activity against fungui, namely, Aspergillus flavus ( A. flavus) and Fusarium species.

Synthesis, Spectral and Antifungal Activity of Ru(II) Mixed‐Ligand Complexes

Several new hexa‐coordinated ruthenium(II) complexes of the type [Ru(CS)(Cl)(Py)(PPh3)(L)], [Ru(CS)(Cl)(Bipy)(L)] and [Ru(Cl)(Phen)(PPh3)(L)], (where Py = pyridine, Bipy = 2,2′‐bipyridyl, Phen = 1,10‐phenanthroline, L = monobasic bidentate Schiff base viz salicylaldehydemethylamine (HSalmet), salicylaldehydecyclohexylamine (HSalchx) and salicylaldehyde‐2‐aminopyridine (HSalampy)) have been synthesized. All of the new complexes have been characterised on the basis of analytical and spectral data. These new complexes showed a reasonable amount of antifungal activity.

SYNTHESIS AND CHARACTERISATION OF RUTHENIUM(III) COMPLEXES CONTAINING MONOBASIC BIDENTATE SCHIFF BASES AND THEIR BIOLOGICAL ACTIVITIES

ABSTRACT New hexa-coordinated ruthenium(III) complexes of the type [RuX2 F(L)(EPh3)2] (X=Cl or Br; L=monobasic bidentate Schiff base ligand; E=P or As) have been synthesised by the reactions of [RuCl3(PPh3)3], [RuCl3(AsPh3)3], [RuBr3-(AsPh3)3] or [RuBr3(PPh3)2(MeOH)] with the appropriate ligands such as anthranilic acid cinnamaldehyde (Hanthcin), anthranilic acid p-tolualdehyde (Hanth-p-tol) and anthranilic acid p-anisaldehyde (Hanth-p-ans). All of these new complexes were characterised using various physico-chemical methods such as elemental analyses, spectral (IR, electronic and EPR), magnetic moment and cyclic voltammetric data. The antibacterial activities of ligands and their complexes have also been determined. An octahedral structure has been tentatively assigned to all of the new complexes.

Synthesis and Biocidal Activity of Isothiocyanato-Chromium(III) Complexes of Some Newly Synthesized Heterocyclic Schiff Bases

Abstract Eight new bidentate Schiff bases were synthesized by reaction of 2-aminobenzothiazole or 2-amino-4-phenyl-5-phenylazothiazole with 2-hydroxy-1-naphthaldehyde or substituted (2-hydroxy-, 4-hydroxy-, 3-methoxy-4-hydroxy-) benzaldehyde. The reaction products of these Schiff bases with potassium hexathiocyanatochromium(III) were of the type: K[Cr(NCS)2(B1)2] and K[Cr(NCS)4(B2)], where HB1 [dbnd] N, O donor monobasic bidentate Schiff bases and B2 [dbnd] N, N donor bidentate Schiff bases. They were characterized on the basis of elemental analysis, molecular mass determination, conductance, magnetic measurements, infrared and UV-visible spectral studies. The complexes were of octahedral structure. Different ligand field parameters 10Dq, B, β35 and C.F.S.E. were calculated and discussed. The Schiff bases and the complexes were also screened for microbiological activity against the fungi Aspergillus niger, Alternaria alternata and bacterium Escherichia coli. The mixed ligand complexes were found more acti...

Synthesis and Characterization of Some Complexes of Indium(III) Chloride with Schiff Bases

Abstract The reactions of indium (III) chloride with some bidentate (SBH) and tridentate Schiff bases (SB'H2) such as, salicylideneaniline (SALAH), salicylidene-o-toluidine (o-SALTH), salicylidene-m-toluidine (m-SALTH), salicylidene-p-toluidine (p-SALTH), 2-hydroxyacetophenone-aniline (o-HyAcPhAH), 2-hydroxy-1-naphthylidene-aniline (o-HyNAH), acetylacetone-o-aminophenol (AcAcAmPH2) and benzoylacetone-o-aminophenol (BacAmPH2) have been carried out in 1:1 or 1:2 molar ratios in dry retrahydrofuran in the presence of tsisthylamine under anhydrous conditions. The compounds of the stoichiometry InC12L, InC1L2 and InC1L′ where L =a monobasic bidentate Schiff base and L′ =a dibasic tridentate Schiff base, have been synthesized and characterized by elemental analysis, molecular weight and spectral (infrared and 1Hn.m.r.) studies

Vibrational spectra of dioxouranium(VI) thiocyanate complexes with monobasic bidentate Schiff bases

AbstractBidentate Schiff base complexes UO2(NCS)2(pBH)2 and UO2(NCS)2(bBH)2 · 2 EtOH(pBH = N‐phenyl salicylindenimin, bBH = N‐benzyl salicylindenimin) have been synthesized and charactetrized. Their infrared and Raman spectra indicate that these complexes have C2h molecular symmetry.

Schiff Base Complexes of Uranium(V) - PART I Novel Synthesis of U(V) Complexes of Monobasic Bidentate Schiff Bases Derived from Salicylaldehyde and Alkylamines

Abstract Schiff base complexes of uranium(V) of the type U(OC2H5)5-x(SB)x (where SB represents the anion of the Schiff bases derived from salicylaldehyde and alkylamines of the type o-HOC6H4 CH[dbnd]NR, where R = C2H5, n-C4H7 or n-C4H9 and x = 1, 2 or 3) have been synthesised in almost quantitative yields by the reactions of uranium pentaethoxide with the Schiff base (SBH) in 1:1, 1:2 and 1:3 molar ratios under anhydrous conditions. Complexes of the type U(OC2H5) (SB) and U(OC2H5)3(SB)2 appear to be dimeric, whereas U(OC2H5)2(SB), type of complexes are monomeric in boiling benzene. The infrared spectra of these complexes show coordination of uranium to oxygen as well as nitrogen. The exchange reactions of some of these complexes in presence of excess of tertiary butanol and phenol have also been carried out.