SYNTHESIS AND SPECTROSCOPIC STUDIES OF SOME NEW REDOX-ACTIVE BENZYLAMINE COMPLEXES OF COPPER(II) AND ESR STUDIES OF THEIR OXIDATIONREDUCTION PRODUCTS

Abstract

New Cu(II) complexes Cu(L′_x)₂, where L′_x=L′₁, L′₂, L′₃, L′₄ are monoanion of unsubstituted, 5-Cl, 5-Br and 3,5-di-Br-substituted 2-hydroxybenzylamines of redox-active N-(3,5-di-tert-butyl-1-hydroxyphenyl)-2-hydroxybenzylamines were synthesized. Each compound of L′_xH and Cu(L′_x)2 as well as products of their oxidation and reduction by PbO2 and PPh3, respectively, was characterized by IR, UV-visible and ESR spectroscopy. ESR results showed that one-electron oxidation of mononuclear tetrahedrally distorted Cu(L′_x)2 chelates with PbO2, via C-C coupling of the Cu(II)-stabilized ligand radical intermediates and by the oxidative dehydrogenation of amine-chelates, produce new Cu(II) complexes with square-planar geometry. The powder ESR spectra of these new Cu(II) complexes exhibit a triplet-state type pattern with the zero-field splitting due to interaction between the copper(II) pairs. Interaction of Cu(L′_x)2 with PPh3 via intramolecular ligand-metal electron transfer results in the formation of radical species and reduction of the metal center. All radical intermediates were characterized by ESR parameters.     

Bis[N-(2,6-di-t-butyl-1-hydroxyphenyl)salicylideneaminato]palladium(II) complexes and their radical intermediates generated by PbO2 and PPh3

New bis[N-(2,6-di-t-butyl-1-hydroxyphenyl)salicylideneminato]palladium(II) [Pd(L ^x )₂] complexes bearing HO and MeO substituents on the salicyaldehyde moiety were prepared, and their spectroscopic properties, as well as redox reactivity towards PbO₂ and PPh₃, examined by e.s.r. and u.v. spectroscopy. The complexes display charge-transfer bands in the 670–692 nm range in polar solvents, which are assigned to the d(Pd) * (chelated quinoid) transition. One-electron oxidation of Pd(L ^x )₂ produces Pd^II-stabilized radicals in which the unpaired electrons are localized on the phenoxy fragments and do not couple with the two radical centers. The complexes are easily reduced with PPh₃ via intramolecular electron-transfer from ligand to metal to give various radical intermediates and Pd. All detected radical species have been characterized by e.s.r. spectroscopy.     

Synthesis, Spectral Characterization and Electrochemical Properties of New vic-dioxime Complexes Bearing Carboxylate

Three new vic-dioxime ligands, [N-(ethyl-4-amino-1-piperidine carboxylate)-phenylglyoxime (L¹H₂), N-(ethyl-4-amino-1-piperidine carboxylate)-glyoxime (L²H₂), and N,N′-bis(ethyl-4-amino-1-piperidine carboxylate)-glyoxime (L³H₂)], and their Co(II) with Cu(II) metal complexes, were synthesized for the first time. Mononuclear complexes of these ligands with a 1:2 metal-ligand ratio were prepared with Co(II) and Cu(II) salts. The BF₂⁺-capped Co(II) and mononuclear complexes of the vic-dioxime were prepared for [Co(L¹·BF₂)₂] and [Co(L²·BF₂)₂]. The ligands act in a polydentate fashion bonding through nitrogen atoms in the presence of a base, as do most vic-dioximes. The cobalt(II) and copper(II) complexes are non-electrolytes as shown by their molar conductivities (Λ_M) in DMF. The structures of the ligands and complexes were determined by elemental analyses, FT-i.r., u.v.–vis., ¹H- and ¹³C-n.m.r. spectra, magnetic susceptibility measurements, and molar conductivity. The comparative electrochemical studies show that the stabilities of the reduced or oxidized species and the electrode potentials of the complexes are affected by the substituents attached on the oxime moieties of the complexes.     

Magnetic measurements and spectral studies on copper(II) complexes of semicarbazones derived from isatin,benzoin and 2-hydroxy-naphthaldehyde

Summary The preparation and spectral properties of five copper(II) complexes of semicarbazones, derived from 2-hydroxy-naphthaldehyde (NPSCZ), benzoin (BZSCZ) and isatin (ISSCZ) are described. I.r., electronic, e.s.r. ¹H and ¹³C n.m.r. spectra show that the semicarbazone's coordination is distorted trigonal bipyramidal for [Cu(BZSCZ-2H)(H₂O)], distorted tetragonal pyramidal for [Cu(NPSCZ)₂](ClO₄)₂ and dimeric for the other three complexes.     

Crystal structures,electrochemical properties,antioxidant screening and in vitro cytotoxic studies on four novel Cu(II) complexes of bidentate Schiff base ligands derived from 2-methoxyethylamine

Four novel Schiff base ligands and their copper(II) complexes, [Cu(L¹)₂] (1), [Cu(L²)₂] (2), [Cu(L³)₂] (3), and [Cu(L⁴)₂] (4), were synthesized and characterized by elemental analyses, FT-IR, and UV–Vis spectroscopy. The ligands were synthesized from the condensation of 2-methoxyethylamine with various salicylaldehyde derivatives (x-salicylaldehyde for HLⁿ, x = H (n = 1), 5-Br (n = 2), 3-OMe (n = 3), and 4-OMe (n = 4)). The molecular structures of 1, 2, and 3 were determined by the single crystal X-ray diffraction technique. The redox behavior studies of the complexes in acetonitrile display the electronic effects of the groups on the redox potential. The antioxidant activity of the Schiff base ligands and their Cu(II) complexes was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method and FRAP assay. Furthermore, the in vitro anticancer activity of compounds was screened, including MTT and migration assays against gastric cancer cell line (MKN-45). The results show that all ligands and complexes have antioxidant and anticancer activity in a concentration-dependent way.     

Synthesis and characterization of mononuclear cadmium(II) and dinuclear uranyl(VI) complexes with <Emphasis Type="Italic">vic</Emphasis>-dioximes

In this study, the mononuclear complexes of cadmium(II) and dinuclear complexes of uranyl(VI) with five vic-dioximes have been obtained. Cadmium(II) forms, with ligands, complexes [(L ^xH)(Cl)(H₂O)(Cd)] with x=1–5. Mononuclear complexes with a metal: ligand ratio of 1:1 were obtained for cadmium(II) with the ligands, and a chloride ion and a water molecule are also coordinated to the cadmium(II) ions. Uranyl(VI) complexes of these ligands are a dinuclear structure with μ-hydroxo-bridges. Uranyl(VI) forms, with ligands, complexes [(L^xH)₂(OH)₂(UO₂)₂] with x=1–5, which have a 2:2 metal:ligand ratio. The structures of the complexes were identified by elemental analysis, i.r., and ¹H-n.m.r. spectra, u.v.–vis. spectroscopy, magnetic susceptibility measurements, conductivity measurements and thermogravimetric analysis (t.g.a.).     

Synthesis,Characterization and Redox Properties of Three New <Emphasis Type="Italic">vic</Emphasis>-dioximes and their Nickel(II) Metal Complexes

Three novel vic-dioximes: cyclohexylamine-p-tolylglyoxime (L₁H₂), t-butylamine-p-tolylglyoxime (L₂H₂) and sec-butylamine-p-tolylglyoxime (L₃H₂) were prepared by the reaction of anti-p-tolylchloroglyoxime with cyclohexylamine, t-butylamine and sec-butylamine in absolute THF. The detection of H-bonding in all of the Ni(II) complexes by i.r. revealed the square-planar MN₄ coordination of mononuclear complexes. MN₄ coordination of the [(L₁H)₂Ni] complex was also determined by ¹H and ¹³C-n.m.r spectroscopy. Mononuclear complexes with a 1:2 metal-ligand ratio were prepared using Ni(II) salts. All Ni(II) complexes are insoluble in common solvents. The ligands and complexes were characterized by elemental analyses, FT-i.r., u.v.–vis., ¹H and ¹³C-n.m.r. spectra, magnetic susceptibility measurements, thermogravimetric analyses (t.g.a.) and cyclic voltammetry.     

Synthesis and structural studies of (2E,3E)-3-[(6-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}pyridin-2-yl)imino]butan-2-one oxime, ligand and its mono-, di- and trinuclear copper(II) complexes

A new dioxime ligand, (2E,3E)-3-[(6-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}-pyridin-2-yl)imino]butan-2-one oxime, (H₂Pymdo) (3) has been synthesized in H₂O by reacting 2,3-butenedione monoxime (2) with 2,6-diaminopyridine. Mono-, di- and tri-nuclear copper(II) complexes of the dioxime ligand (H₂Pymdo) and/or 1,10-phenanthroline have been prepared. The dioxime ligand (H₂Pymdo) and its copper(II) complexes were characterized by ¹H-n.m.r., ¹³C-n.m.r. and elemental analyses, magnetic moments, i.r. and mass spectral studies. The mononuclear copper(II) complex of H₂Pymdo was found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes, in which the first Cu(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms. The trinuclear copper(II) complex (6) was formed by coordination of the third Cu(II) ion with dianionic oxygen atoms of each of two molecules of the mononuclear copper(II) complexes. The data support the proposed structure of H₂Pymdo and its Cu(II) complexes.     

Synthesis and spectroscopic studies of transition metal dinuclear/ polynuclear complexes with azolo-2,4-pentanedione

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.     

Synthesis,characterization and ascorbic acid oxidase mimetic catalytic activity of copper(II) picolyl hydrazone complexes

Four new picolyl hydrazones were prepared via Schiff-base condensation of picolonic acid hydrazide with α-formyl-(L¹), α-acetyl-(L²), α-benzoyl-(L³) pyridine and α-formyl-(L⁴) thiophene. Copper(II) complexes of these hydrazones and a series of copper(II) complexes containing (L²) and various anions (Cl, Br, NO₃, SCN, SO₄, ClO₄, AcO, PF₆ and BF₄) have been synthesized. Elemental, thermal analysis, molar conductivity, magnetic moment measurements and spectral (i.r., electronic and e.s.r.) studies have been used to characterize the prepared compounds. The overall structure and reactivity of the reported copper(II) chelates critically depend on the ligand structure and the nature of counter anion incorporated in the complex molecule. Octahedral [complex (7)], square-pyramidal [complex (8)] and square-planar monomeric species [complexes (1–6), (9) and (10)] and a dimeric structure with oxygen bridge in square-planar geometry [complexes (11) and (12)] were suggested. The reported copper(II) complexes exhibit promising oxidase catalytic activity towards the aerobic oxidation of vitamin C. A linear correlation exists between the oxidase catalytic activity and the Lewis-acidity of the central copper(II) ion created by the donating properties of the parent ligand, as well the irregularity of the coordination environment. The probable mechanistic implications of the catalytic oxidation reactions are discussed.     

Synthesis,structural characterization,antimicrobial, DNA-binding,and photo-induced DNA cleavage activity of some bio-sensitive Schiff base copper(II) complexes

Schiff base mixed-ligand copper complexes [CuL¹(phen)Cl₂], [CuL¹(bipy)Cl₂], [Cu(L¹)₂Cl₂], [Cu(L²)₂Cl₂], [CuL²(bipy)Cl₂], and [CuL²(phen)Cl₂] (where L^1?=?4-[3,4-dimethoxy-benzylidene]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazole-3-one; L^2?=?4-[3-hydroxy-4-nitro-benzylidene]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazole-3-one; phen?=?1,10-phenanthroline; and bipy?=?2,2′-bipyridine) have been synthesized and characterized. Their DNA-binding properties have been studied by electronic absorption spectra, viscosity, and electrochemical measurements. The absorption spectral and viscosity results suggest that the copper(II) complexes bind to DNA via partial intercalation. The addition of DNA resulting in the decrease of the peak current of the copper(II) complexes indicates their interaction. Interaction between the complexes and DNA has also been investigated by submarine gel electrophoresis. The copper complexes cleave supercoiled pUC19 DNA to nicked and linear forms through hydroxyl radical and singlet oxygen in the presence of 3-mercaptopropionic acid as the reducing agent. These copper complexes promote the photocleavage of pUC19 DNA under irradiation at 360?nm. Mechanistic study reveals that singlet oxygen is likely to be the reactive species responsible for the cleavage of plasmid DNA by the synthesized complexes. The in vitro antimicrobial study indicates that the metal chelates have higher activity against the bacterial and fungal strains than the free ligands.     

Synthesis and structural studies of (2 E ,3 E ,6 R ,9 E ,11 E )-6-isopropenyl-3,6,10-trimethyl-5,8-dioxa-4,9-diazadodeca-3,9-diene-2,11-dione dioxime, ligand and its Mono-, homo, and heterodinuclear copper(II)/nickel(II) complexes

This article describes the synthesis of a new (2E,3E,6R,9E,11E)-6-isopropenyl-3,6,10-trimethyl-5,8-dioxa-4,9-diazadodeca-3,9-diene-2,11-dione dioxime (H₂hmdm), and its mono-, homo, and heterodinuclear copper(II)/nickel(II) complexes. Elemental analyses, stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). The Cu(H₂hmdm), molecule coordinates to the second copper(II) ion through the oximate oxygens to afford a binuclear structure doubly bridged by the oximate groups in the cis arrangement. In the dinuclear complexes, in which the first Cu^II ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu^II ion is ligated with the 1,10-phenanthroline nitrogen atoms. Ligand and its mononuclear copper(II), homo and heterodinuclear copper(II)–nickel(II) complexes of (H₂hmdm) were characterized by elemental analyses, magnetic moments, ¹H-n.m.r. and ¹³C-n.m.r., i.r., and mass spectral studies. The data support the proposed structure of H₂hmdm and its complexes.     

Copper(II) and palladium(II) complexes of 2-amino-5-chlorobenzophenone and 2-(2-hydroxybenzylidene)amino-5-chlorobenzophenone-<Emphasis Type="Italic">S</Emphasis>-methyl-thiosemicarbazones

The S-methyl thiosemicarbazone derivatives of 2-amino-5-chlorobenzophenone and 2-(2-hydroxybenzylidene)amino-5-chlorobenzophenone (L^I and L^II) and their copper(II) and palladium(II) chelates were synthesized. The solid compounds, [Cu(L^I)Cl]Cl · 2H₂O, [Cu(L^II)Cl]Cl · H₂O, [Pd(L^I)Cl]Cl, and [Pd(L^II)Cl₂], were characterized by elemental analysis, thermogravimetric measurements, electronic, i.r., ¹H-n.m.r. and e.p.r. spectroscopy. The ligand behavior of the L^I and L^II explained by means of spectroscopic data. The experimental X-band e.p.r. spectra recorded from two different copper(II) ion coordinated powder complexes have characteristic line shapes that exhibit the axial symmetry around the paramagnetic ions. The theoretically well fitted spectra prove this case too. The absence of hyperfine signals has been attributed to the strong covalency effects of copper electrons with neighbouring N atoms. Orbital energy levels for magnetic electrons were determined from Spin Hamiltonian parameters. The anisotropic Lande splitting factors were specified in an order of and this case indicates that the unpaired electrons are located mainly in the orbital.     

Copper and palladium complexes with substituted pyrimidine-2-thiones and 2-thiouracils: syntheses,spectral characterization,and X-ray crystallographic study

Copper(I) and palladium(II) complexes containing 5-acetyl-6-methyl-1,2,3,4-tetrahydropyrimidine-2-thione (L¹), ethyl 4,6-dimethyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (L²), cis-5-acetyl-6-ethyl-5,6-dihydro-2-thiouracil (L³), and 5,6-dihydro-2-thiouracil (L⁴) have been synthesized. All complexes were characterized by elemental analysis, IR, ¹H, and ¹³C NMR spectroscopy. To assign bands in the IR spectra of L¹ and L² and complexes with Cu(I) and Pd(II), deuterium substitution of movable protons at N-atoms was used. The crystal structures of two compounds, [Cu(L²)₂Cl] and [Pd(L⁴)₂Cl₂], were determined by X-ray single-crystal and powder diffraction, respectively. In [Cu(L²)₂Cl], copper has a rare coordination number of three and triangular surrounding of two neutral L² molecules, coordinated through sulfurs, and chloride. In [Pd(L⁴)₂Cl₂], palladium has a standard square-planar geometry, formed by two uracil molecules and two chlorides. A new method for the synthesis of 5,6-dihydro-2-thiouracil, starting from β-aminopropionic acid, was suggested.     

Binuclear copper(II) complexes of 5-nitrosalicylaldehyde N(3)-substituted thiosemicarbazones

Summary Binuclear copper(II) complexes with six 5-nitrosalicylaldehyde N(3)-substituted thiosemicarbazones have been prepared and characterized. I.r., electronic and e.s.r. spectra of the complexes, as well as i.r., electronic, and ¹H-and ¹³C-n.m.r. spectra of the thiosemicarbazones, have been obtained. The crystal structure of a monomeric copper(II) complex of 5-nitrosalicylaldehyde piperidyl-thiosemicarbazone, H₂5NO₂Sapip, grown from DMF solution, has been solved. Neither the thiosemicarbazones or their binuclear copper(II) complexes show growth inhibitory activity against Aspergillus niger, but the copper(II) complexes show some activity against the fungus Paecilomyces variotii.     

Decomposition of Copper Formate Clusters: Insight into Elementary Steps of Calcination and Carbon Dioxide Activation

The decomposition of copper formate clusters is investigated in the gas phase by infrared multiple photon dissociation of Cu(II)_n(HCO₂)_2n+1⁻, n≤8. In combination with quantum chemical calculations and reactivity measurements using oxygen, elementary steps of the decomposition of copper formate are characterized, which play a key role during calcination as well as for the function of copper hydride based catalysts. The decomposition of larger clusters (n > 2) takes place exclusively by the sequential loss of neutral copper formate units Cu(II)(HCO₂)₂ or Cu(II)₂(HCO₂)₄, leading to clusters with n=1 or n=2. Only for these small clusters, redox reactions are observed as discussed in detail previously, including the formation of formic acid or loss of hydrogen atoms, leading to a variety of Cu(I) complexes. The stoichiometric monovalent copper formate clusters Cu(I)_m(HCO₂)_m+1⁻, (m=1,2) decompose exclusively by decarboxylation, leading towards copper hydrides in oxidation state +I. Copper oxide centers are obtained via reactions of molecular oxygen with copper hydride centers, species containing carbon dioxide radical anions as ligands or a Cu(0) center. However, stoichiometric copper(I) and copper(II) formate Cu(I)(HCO₂)₂⁻ and Cu(II)(HCO₂)₃⁻, respectively, is unreactive towards oxygen.     

Synthesis,spectroscopic and electrochemical studies of copper(II) and cobalt(II) complexes of three unsymmetrical vic -dioximes ligands

Cobalt(II) and copper(II) complexes with three dioxime ligands cyclohexylamine-p-tolylglyoxime (L₁H₂), tert-butyl amine-p-tolylglioxime (L₂H₂) and sec-butylamine-p-tolylglyoxime (L₃H₂), have been prepared. The metal to ligand ratios of the complexes were found to be 1?:?2. The Cu(II) complexes of these ligands are proposed to be square planar; the Co(II) complexes are proposed to be octahedral with water molecules as axial ligands. Ligands and complexes are soluble in common solvents such as DMSO, DMF, CHCl₃ and C₂H₅OH. The ligands have been characterized by elemental analysis, IR, UV-VIS, ¹H?NMR, ¹³C?NMR and thermogravimetric analysis (TGA). The complexes were characterized by elemental analysis, IR, UV-VIS, magnetic susceptibility measurements, thermogravimetric analysis (TGA) and electrochemistry. Electrochemical properties of metal complexes show quasi-reversible one-electron redox processes. However, Co(L₁H)₂ and Cu(L₁H)₂ complexes show another oxidation peak in the positive region. This single irreversible oxidation peak is caused by the cyclic ring of the ligand. Data also revealed that the electron transfer rates of metal complexes with L₁H₂ are higher than the other complexes.     

In vitro antifungal and antibacterial properties of thiodiamine transition metal complexes

Synthesis, characterization and biological studies of some thiodiamine metal complexes are described. Cobalt(II) and copper(II) complexes of type [Cu(L)₂Cl₂] and [Co(L)₂SO₄], where L = (cyclohexyl-N-thio)-1,2-ethylenediamine (L¹) and (cyclohexyl-N-thio)-1,3-propanediamine (L²), were synthesized. The synthesized copper and cobalt thiodiamine complexes were characterized by elemental analysis, IR, mass, UV-VIS and ¹H NMR spectroscopic studies. Thiodiamines coordinate as a bidentate N-S ligand. The binding sites are azomethine nitrogen and thioamide sulfur. Molar conductance values in dimethylsulfoxide indicate non-electrolyte nature of the complexes. In vitro-antimicrobial screening shows promising results against both bacterial and fungal strains.     

Synthesis,characterization, and biological activity studies on (E)-N′-[2-hydroxy-1,2-di(pyridin-2-yl)ethylidine]aroyl hydrazides and their copper(II) complexes

The reaction of copper(II) salts with (E)-N-(2-hydroxy-1,2-di(pyridin-2-yl)ethylidene)aroyl hydrazide (H₂L¹, H₂L², H₃L³) or (E)-N-(2-hydroxy-1,2-di(pyridin-2-yl)ethylidene) isonicotinohydrazide (H₂L⁴) afforded the complexes [(L)Cu(H₂O)₃], [(H₂L)Cu(OAc)(H₂O)], [(HL)Cu(OAc)] _n , [(H₂L)Cu(H₂O)](ClO₄)₂ and [(H₂L)Cu(OAc)(H₂O)], where n = 1 or 2 and L is the dinegative ion of the ligands. The ligands and their complexes are characterized by elemental analyses, spectral (IR, NMR, electronic, and ESR) and magnetic studies. The FT-IR indicates that the ligands are neutral or anionic polydentate. The number of the coordinating centers depends on the nature of the metal used and the reaction conditions. The room temperature magnetic moment values, electronic spectra and ESR data indicate square planar, trigonal bipyramidal, square pyramidal, and distorted octahedral ligand fields around copper(II). Thermal decomposition of the complexes was monitored by TG and DTG under N₂ and the thermal decomposition mechanisms are given. The compounds were screened for their antimicrobial activities on some Gram-positive and Gram-negative bacterial species. The free ligands are inactive against all studied bacteria. The complexes have variable activity with the most active [(H₂L)Cu(H₂O)](ClO₄)₂, where H₂L is H₂L¹ or H₂L². The minimum inhibition concentrations for these two complexes were determined. These biological activity results are related to the structures of the compounds.     

Synthesis,spectroscopic and the biological activity studies of thiosemicarbazones containing ferrocene and their copper(II) complexes

Two Schiff bases, 1-acetylferrocene thiosemicarbazone (HL¹) and 1,1′-diacetyl-ferrocene dithiosemicarbazone (H₂L²) and their copper(II) complexes were prepared and characterized by elemental analysis, magnetic susceptibility, conductivity, and spectral (IR, UV–Vis, ESR) measurements The IR spectra showed that HL¹ acts as neutral or monobasic bidentate ligand, coordinating to copper(II) through either thiono- or thiolo-sulphur and azomethine-N atoms, whereas H₂L² is a neutral or dibasic mononucleating or binucleating quadridentate ligand coordinating through the same atoms. Other spectral measurements indicate that complexes [(L¹)₂Cu], [(L²)Cu] and [(HL¹)₂Cu]X₂, X?=?Cl, Br or ClO₄ have square-planar geometry around copper(II) while [(HL¹)CuX₂] and [(H₂L²)Cu₂X₄], X?=?Cl or Br, have distorted tetrahedral geometry. The biological activity studies of the complexes and the free ligands towards two gram positive and two gram negative bacteria and one fungal species have been studied and the potential is related to the nature and structure of the tested compounds.