Synthesis,characterization, and investigations of antimicrobial activity of 6,6-dimethyl-3-aryl-3′,4′,6,7-tetrahydro-1′H,3H-spiro[benzofuran-2,2′-naphthalene]-1′,4(5H)-dione

Chalcone-like compounds 3a–l, 2-(benzylidene)-3,4-dihydronaphthalen-1(2H)-one, were synthesized from the addition of different benzaldehyde derivatives (2a–l) to 1,2,3,4-tetrahydro-1-napthalone (1) in basic medium. Mn(OAc)₃-mediated addition of dimedone (4) to chalcone-like compounds gave the spirobenzofuran derivatives (5a-l), 6,6-dimethyl-3-aryl-3′,4′,6,7-tetrahydro-1′H,3H-spiro[benzofuran-2,2′-naphthalene]-1′,4 (5H)-dione, in good yields. The structures of synthesized compounds 5a–l were elucidated on basis of spectral data (NMR, IR) and elemental analysis. In addition, their antibacterial activities were screened against some human pathogenic microorganisms.     

Two hydrazones derived from 1‐aryl‐3‐(p‐substituted phenyl)prop‐2‐en‐1‐one: synthesis,crystal structure,Hirshfeld surface analysis and in vitro biological properties

Two chalcones were synthesized by the aldolic condensation of enolizable aromatic ketones with substituted benzaldehydes under Claisen–Schmidt reaction conditions and then treated with 2,4‐dinitrophenylhydrazine to yield their corresponding hydrazones. The two (E,Z)‐2,4‐dinitrophenylhydrazone structures, namely (Z)‐1‐(2,4‐dinitrophenyl)‐2‐[(E)‐3‐(4‐methylphenyl)‐1‐phenylallylidene]hydrazine, C₂₂H₁₈N₄O₄, ( H1 ), and (Z)‐1‐[(E)‐3‐(4‐chlorophenyl)‐1‐(naphthalen‐1‐yl)allylidene]‐2‐(2,4‐dinitrophenyl)hydrazine, C₂₅H₁₇ClN₄O₄, ( H2 ), were isolated by recrystallization and characterized by FT–IR, UV–Vis, single‐crystal and powder X‐ray diffraction methods. The UV–Vis spectra of the hydrazones have been studied in two organic solvents of different polarity. It was found that ( H2 ) has a molar extinction coefficient larger than 40000. Single‐crystal X‐ray diffraction analysis reveals that the molecular zigzag chains of ( H1 ) and ( H2 ) are interconnected through noncovalent contacts. A quantitative analysis of the intermolecular interactions in the crystal structures has been performed using Hirshfeld surface analysis. All the synthesized chalcones and hydrazones were evaluated for their antibacterial and antioxidant activities. Results indicate that the studied compounds show significant activity against Gram negative Escherichia coli strain and the chalcone 3‐(4‐methylphenyl)‐1‐phenylprop‐2‐en‐1‐one, ( C1 ), was the most effective. In addition, only hydrazone ( H1 ) displayed a moderate DPPH (2,2‐diphenyl‐1‐picryl hydrazyl) scavenging efficiency.     

Dicationic liquid mediated synthesis of tetrazoloquinolinyl methoxy phenyl 4-thiazolidinones and their antibacterial and antitubercular evaluation

In a search of new potentially active antitubercular agents here we have synthesized 3-substituted phenyl-2-(4-(tetrazolo[1,5-a]quinolin-4-ylmethoxy)phenyl)thiazolidin-4-ones (8a–l) and evaluated their antibacterial, particularly antitubercular activity. These have been conveniently synthesized by performing one–pot cyclocondensation of 4-(tetrazolo[1,5-a]quinolin-4-ylmethoxy)benzaldehyde, anilines and mercaptoacetic acid in dicationic ionic liquid, (3-methyl-1-[3-(methyl-1H-imidazolium-1-yl)propyl]-1H-imidazolium dibromide [C₃(MIM)₂–2Br]) and obtained excellent yields of (8a–l). 4-Thiazolidinones (8a–l) were thoroughly characterized by their spectral analyses. These compounds have been screened for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Ra and Mycobacterium bovis (BCG). The compounds 8a, 8c, and 8e exhibited notable in vitro antitubercular activity compare to the reference, Rifampicin. Molecular docking study has also been performed to know the binding mode of these analogs in to the active site of DprE1 enzyme. The synthesized compounds were also evaluated for their in vitro antibacterial activity and amongst them compound 8k has shown moderate activity against both gram-negative and gram-positive bacterial strains.     

Synthesis and characterization of binary and ternary oxovanadium complexes of N,N′‐(2‐pyridyl)thiourea and curcumin: Catalytic oxidation potential,antibacterial, antimicrobial,antioxidant and DNA interaction studies

Two binary and two ternary mono‐oxovanadium (IV) complexes of acetylacetonate, curcumin and N ,N ′‐bis(2‐pyridyl)thiourea were synthesized. They were characterized using elemental analysis, infrared and UV–visible spectroscopies and magnetic and conductivity measurements. The formation constants K _f were determined from spectrophotometric measurements. The catalytic potential of the VO complexes was investigated for the oxidation of 1‐octene by aqueous H₂O₂ in acetonitrile. They display high catalytic potential for the conversion of 1‐octene with low chemoselectivity to the epoxy product. The VO complexes exhibit good antibacterial and antimicrobial activities. The antioxidant activity of the VO complexes and their ligands was investigated. The VO complexes show high DNA affinity and DNA cleavage ability.     

Synthesis,characterization, and antimicrobial activity of new benzoylthiourea ligands

In this study, new benzoylthiourea derivatives, (E)-N-[(2-benzamidomethyleneamino)ethylcarbamothioyl]benzamide H₃L′, N-(1-(3-benzoylthioureido)propan-2-ylcarbamothioyl)-benzamide H₄L″, (E)-N-[4-(benzamidomethyleneamino)phenylcarbamothioyl]benzamide H₃L‴, were synthesized. Structures of the compounds were identified by spectroscopic techniques. In addition, all synthesized compounds were evaluated for in vitro antibacterial and antifungal activity. Compound H₃L‴ exhibited antibacterial activity.     

Synthesis,characterization and bioactivity of Schiff base copper(II) complexes derived from L-glutamine and L-asparagine

To investigate the structure–activity relationship of L-glutamine and L-asparagine Schiff base copper complexes in applications, L-glutamine and L-asparagine Schiff bases (GV and AV) and their copper complexes [Cu₃(GV)₂(CH₃COO)₂(H₂O)] · 2H₂O (GVC) and [CuAV(H₂O)₃] (AVC) have been synthesized and characterized by molar conductance, elemental analysis, UV-Vis, IR, ¹H-NMR, and TG-DTG. We examined the geometries of GV, AV, GVC, and AVC through Hartree–Fock method and electronic absorption spectra. We also tested their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis bacteria and antiproliferation activity on human breast cancer MDA-MB-231 cells. The side chain difference between L-glutamine and L-asparagine results in different geometry of GV and AV, which leads to different geometry of GVC and AVC. GVC, a trinuclear Cu(II) complex, shows the highest antibacterial activity and the highest growth inhibition activity on MDA-MB-231 cells. Our results suggest that GVC has potential as an antibacterial and anticancer agent.     

Synthesis,Structures, and Antibacterial Activities of Four Similar 1D Metal-organic Polymers with Different Metal Ions

Four similar 1D metal-organic polymers [Cd(impc)₂(H₂O)₂]_n ( 1 ), [Co(impc)₂(H₂O)₂]_n ( 2 ), [Mn(impc)₂(H₂O)₂]_n ( 3 ), and {[Cu(impc)₂] · [jy2H₂O}_n ( 4 ) based on an asymmetric 5-(1H-imidazole-l-yl)-3-pyridinecarboxylic acid (Himpc) were prepared hydrothermally and structurally characterized. According to the frontier molecular orbital (FMOs) calculations, the photoluminescence of 1 should be assigned as the n→π* transition. The antibacterial properties of 1 – 4 were studied. 1 exhibited good antibacterial activities towards B. subtilis and S. aureus with the smallest MIC value of 2 μg · mL^–1. Compared with Co^II, Mn^II and Cu^II ions, the polymer with Cd^II ion has the better antibacterial activity. Our work preliminarily reveals that the metal ions also have different influences on antibacterial activities of complexes.     

Synthesis and antibacterial activities of metal(II) complexes with Schiff bases derived from 3,5-diiodosalicylaldehyde

Two new Schiff bases (2,4-diiodo-6-[(2-morpholin-4-yl-ethylimino)-methyl]-phenol and 2,4-diiodo-6-[(3-morpholin-4-yl-propylimino)-methyl]-phenol), condensed from 3,5-diiodosalicylaldehyde with 2-morpholinoethylamine and 3-morpholinopropylamine, have been designed and synthesized. Reaction of the Schiff bases with Zn(OAc)₂ · 2H₂O, Cu(OAc)₂ · H₂O, Ni(OAc)₂ · 4H₂O, Co(OAc)₂ · 4H₂O, Cd(OAc)₂ · 2H₂O, Mn(OAc)₂ · 4H₂O, Fe(SO4)₂ · 7H₂O, and Hg(OAc)₂ led to the formation of 16 new mononuclear complexes. The complexes were characterized by UV, Infrared, ESI-MS, and elemental analyses, and 3,5-diiodosalicylalidene-2-morpholinoethylaminozinc(II) (1) and 3,5-diiodosalicylalidene-2-morpholinoethylaminocopper(II) (2) were characterized by single crystal X-ray diffraction. Based on crystal structural analysis of 1 and 2, coupled with their spectral similarity with 3–16, it can be concluded that 3–16 have structures similar to 1 and 2. All the complexes were assayed for antibacterial activities against three Gram positive bacterial strains (Bacillus subtilis, Staphylococcus aureus, and Streptococcus faecalis) and three Gram negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter cloacae) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. Among the complexes tested, 8 and 16 showed the most favorable antibacterial activity with minimum inhibitory concentration of 0.781, 12.5, 6.25, 3.125, 3.125, 6.25 and 1.562, 6.25, 1.562, 3.125, 3.125, 1.562 µg mL^?1 against B. subtilis, S. aureus, S. faecalis, P. aeruginosa, E. coli, and E. cloacae, respectively.     

Synthesis,characterization and antibacterial studies of some new tellurated azo compounds

A series of tellurated azo compounds [i.e. (4-HOC₆H₄N=N-Ar)TeBr₃ and (4-HOC₆H₄N=N-Ar)₂TeBr₂, where Ar=5-BrC₆H₃, 5-CH₃C₆H₃ and 5-NO₂C₆H₃] were prepared by the reaction of the corresponding 2-(4-hydroxyphenylazo)aryl mercury chloride with tellurium tetrabromide in 1:1 and 2:1?mole ratio, respectively in dry dioxane as a solvent. The reduction of (4-HOC₆H₄N=N-Ar)TeBr₃ by hydrazine hydrate gave the corresponding ditelluride (i.e., (4-HOC₆H₄N=N-Ar)₂Te₂). Treatment of (4-HOC₆H₄N=N-Ar)₂TeBr₂ with hydrazine hydrate afforded the corresponding tellurides, (4-HOC₆H₄N=N-Ar)₂Te), in good yields. The structures of all newly synthesized compounds were assigned on the basis of their elemental and spectroscopic data. The antibacterial activity of tellurated azo compounds along with mercurated azo compounds was tested with agar diffusion method against the bacteria strains Staphylococcus aureus and Escherichia coli. The antibacterial activities of tellurated azo compounds were in some cases equal or better than those of the reference drug. The mercurated azo compounds were found to be the more antibacterial activity of than those of tellurated azo compounds.     

Synthesis,spectroscopic, antimicrobial and anti-inflammatory studies of 5(2′-hydroxyphenyl)-3-(4-x-phenyl)pyrazolinates of copper(II) and their addition complexes with donor ligands

Complexes of copper(II) with 5(2′-hydroxyphenyl)-3-(4-x-phenyl)pyrazolines, (C₁₅H₁₂N₂OX)₂Cu [X =–H,–Cl,–CH₃,–OCH₃] have been synthesized with their addition complexes with 2,2′-bipyridine, 1,10-phenanthroline and triphenylphosphine. The complexes were characterized by elemental analyses, molecular weight measurement, magnetic, conductivity measurement, IR, electronic, ³¹P NMR, ESR and FAB mass spectra. The complexes were examined for crystalline/amorphous nature through XRD. Square-planar geometry around copper(II) is suggested with two bidentate pyrazoline ligands. In the additional complexes pyrazoline is monodentate. The bidentate and monodentate behavior of pyrazoline ligands was confirmed by IR and ³¹P NMR spectral data. All complexes were tested for in vitro antibacterial and antifungal activity and exhibit very good antibacterial and antifungal activity; coordination has a pronounced effect on the microbial activities. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties. All complexes and adducts displayed potent cytotoxic activity against Artemia salina. Anti-inflammatory activity was also carried out by the carrageenan induced rat paw edema test. The complexes and adducts were found to have higher anti-inflammatory activity.     

Synthesis,Bioactivity, and the Anion‐Binding Property of 2‐Sulfydryl‐1,3,4‐thiodiazole Derivatives

Two new compounds ( 1 and 2 ) containing 2‐sulfydryl‐1,3,4‐thiodiazole have been synthesized and optimized. They both showed wide antibacterial activity for colon bacillus, Staphylococcus aureus, S. albus, dysentery bacillus and inferior activity for Bacillus subtilis. In addition, their binding properties were evaluated for biologically important anions (F^–, Cl^–, Br^–, I^–, AcO^–, and H₂PO₄^–) by theoretical investigation, UV–vis, fluorescence, and ¹H NMR titration experiments, and they displayed strong binding ability for H₂PO₄^– without the interference of other anions tested. Especially the binding ability of compound 2 containing anthracene with H₂PO₄^– was 1000 times stronger than that of compound 1 containing nitrobenzene. Two compounds based on 2‐sulfydryl‐1,3,4‐thiodiazole have both properties of anion recognition and antibacterial activity.     

Investigation and comparison of biological effects of regioselectively synthesized thiazole derivatives

In this study, anticancer, antibacterial (against hospital-isolated antibiotic-resistant Escherichia coli strains), antifungal, and antioxidant effects of synthesized heterocyclic compounds 5 and 7 containing thiazole core were examined. Cytotoxicity testing was utilized against MCF-7 breast cancer cells via MTT cell viability assay. Antibacterial and antifungal activities were checked out according to Clinical and Laboratory Standards Institute (CLSI) guidelines, and antioxidant properties were evaluated through scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals. Results showed the viability of breast cancer cell lines was reliant on concentration of heterocycles and time of incubation. Synthetic compounds exhibited excellent antibacterial and antifungal properties base on their minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) values as well as high antioxidant activities according to their IC₅₀ values. Higher anticancer and antibacterial properties were observed with compound 7; on the contrary, thiazole 5 had better antioxidant effects. They can be introduced as potent antimicrobial, antioxidant, and anticancer agents.     

Construction and properties of drug molecules modifying octamolybdate hybrid compounds

By introducing antibacterial drug pipemidic acid into octamolybdates, two new compounds, (HPPA)₄[Mo₈O₂₆] 2H₂O (1) and [Ni₂(PPA)₂(H₂O)₄] [Mo₈O₂₆] 3H₂O (2) (PPA?=?8-ethyl-5,8-dihydro-5-oxo-2-(1-piperazinyl)pyrido(2,3-d)pyrimidine-6-carboxylic acid), have been synthesized and characterized by physical methods. Single-crystal X-ray analysis reveal that 1 and 2 crystallize in the triclinic system, space group P-1, in which supramolecular interactions play vital roles in stabilizing the structure of 1 and 2. The results of their antitumor activities in vitro show that the compounds exhibit good anti-SGC7901 and anti-SMMC7721 activities, which indicates that the antitumor activities of Polyoxometalates can be modulated by the surface modification with drugs.     

Synthesis,structure, ADME and biological activity of three 2,6-disubstituted thiosemicarbazone derivatives

Three new 2,6-disubstituted thiosemicarbazone derivatives of pyridine, namely, 2-{amino[6-(pyrrolidin-1-yl)pyridin-2-yl]methylidene}-N,N-dimethylhydrazine-1-carbothioamide, C₁₃H₂₀N₆S, 2-{amino[6-(piperidin-1-yl)pyridin-2-yl]methylidene}-N,N-dimethylhydrazine-1-carbothioamide, C₁₄H₂₂N₆S, and 2-[amino(6-phenoxypyridin-2-yl)methylidene]-N,N-dimethylhydrazine-1-carbothioamide monohydrate, C₁₅H₁₇N₅OS·H₂O, have been synthesized and characterized by NMR spectroscopy and low-temperature single-crystal X-ray diffraction. In addition, their antibacterial and anti-yeast activities have been determined. The ability of the tested compounds to inhibit bacterial growth was comparable to vancomycin as a reference drug. Compared to isoniazid (MIC 0.125 and 8 µg ml⁻¹), the compounds showed the ability to inhibit the growth of Mycobacterium tuberculosis to a moderate degree for the standard strain and at the same level or higher (MIC 4–8 µg ml⁻¹) for the resistant strain. All three compounds adopt the zwitterionic form in the crystal structure regardless of the presence or absence of solvent molecules.     

Synthesis and investigation of antibacterial activities and carbonic anhydrase and acetyl cholinesterase inhibition profiles of novel 4,5-dihydropyrazol and pyrazolyl-thiazole derivatives containing methanoisoindol-1,3-dion unit

Novel 4,5-dihydropyrazole derivatives (3a–i), 3-(4-((3aR,4S,7R,7aS)-1,3-dioxo-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindol-2(3H)-yl)phenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbothio amide, were obtained by the addition of thiosemicarbazide (2) to the chalcones (1a–i). The addition–cyclization of 2,4′-dibromoacetophenone (4) to pyrazole derivatives (3a–i) gave the new pyrazolyl-thiazole derivatives (5a–i), (3aR,4S,7R,7aS)-2-(4-(1-(4-(4-bromophenyl)thiazol-2-yl)-5-phenyl-4,5-dihydro-1H-pyrazol-3-yl)phenyl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione. Antibacterial and acetylcholinesterase (AChE) enzyme and human carbonic anhydrase (hCA) I, and II isoform inhibitory activities of the compounds 3a–i and 5a–i were investigated. Some of the compounds showed promising antibacterial activity. In addition, the hCA II and I were effectively inhibited by the lately synthesized derivatives, with K_i values in the range of 18.90?±?2.37 ?58.25?±?13.62?nM for hCA II and 5.72?±?0.98 ?37.67?±?5.54?nM for hCA I. Also, the K_i parameters of these compounds for AChE were obtained in the range of 25.47?±?11.11???255.74?±?82.20?nM. Also, acetazolamide, clinical molecule, was used as a CA standard inhibitor that showed K_i value of 70.55?±?12.30?nM against hCA II, and 67.17?±?9.1?nM against hCA I, and tacrine inhibited AChE showed K_i value of 263.67?±?91.95.     

Synthesis,antimicrobial and antioxidant activity of bis sulfonamide/carbamate derivatives of bis-(4-aminophenyl) methane

A series of new bis sulfonamide/carbamate derivatives of bis-(4-aminophenyl)methane 3 ( a–d )/ 5 ( a–f ) were synthesized from bis-(4-aminophenyl)methane ( 1 ) using various pharmacologically active sulfonyl chlorides 2 ( a–d ) and carbonochloridates 4 ( a–f ) in high yields. The structures of all the newly synthesized compounds were characterized by the Infrared spectroscopy, NMR (¹H and ¹³C), mass, and elemental analyses. Further, all the synthesized compounds were tested for the antioxidant activity by using 2, 2-diphenyl-1-picrylhydrazyl, NO, and H₂O₂ scavenging methods and antimicrobial activity. Most of the compounds exhibited good antioxidant and antimicrobial activities.     

Synthesis,spectroscopic characterization,and biological screening of levofloxacin based organotin(IV) derivatives

Four new organotin (IV) complexes with general formula R₃SnL/R₂SnL₂, where R = CH₃, n-C₄H₉, C₆H₅ and L = Levofloxacin, were synthesized and characterized by elemental analyses, FT-IR and NMR (¹H and ¹³C) spectroscopy. Spectroscopic data suggested a six-coordinated geometry for diorganotin(IV) derivatives and a five-coordinated geometry for triorganotin(IV) derivatives. The value of Me–Sn–Me bond angle for di- and trimethyltin complexes using the Lockhart equation, were 150° and 116°, respectively, that corresponded to six and five-coordinate geometry, accordingly. The ligand and its complexes were screened for their antibacterial, antifungal, cytotoxic, and free radical scavenging (DPPH) antioxidant activities. The biological data indicated those as potentially bioactive in each field of the study. Accumulated data of DNA interaction with the synthesized complexes based on UV-Vis, cyclic voltammetry and viscometry suggested an intercalative mode of the interaction.     

Synthesis,spectroscopic (IR,electronic, FAB-mass,and PXRD), magnetic,and antimicrobial studies of new iron(III) complexes containing Schiff bases and substituted benzoxazole ligands

Mixed ligand complexes of iron(III), [Fe(sb)₂(py)Cl]?·?2H₂O (1–9) [where sbH?=?Schiff bases (derived from condensation of 2-aminopyridine (sapH), 2-aminophenol (saphH), o-toluidine (o-smabH), aminobenzene (sabH), p-toluidine (p-smabH), 3-nitroaniline (snabH), and anthranilic acid (saaH) with salicylaldehyde and substituted (mercapto-)benzimidazole (mbzH), {2-(o-hydroxyphenyl)}benzoxazole, (pboxH)], have been synthesized by the interactions of iron(III) chloride with corresponding ligands in 1?:?2 molar ratio in refluxing pyridine. These complexes have been characterized by elemental analyses, melting points, spectral, and magnetic studies. Powder X-ray diffraction studies of some representative complexes are also reported herein. The antibacterial and antifungal activities of the free ligands and their iron(III) complexes were found in vitro. The complexes showed good antibacterial and antifungal effect to some bacteria and fungi. Two standard antibiotics (chloromphenicol and terbinafine) were used for comparison with these complexes.     

Synthesis of novel 1,2,3-thiadizoles and 1,2,3-selenadiazoles as new antimicrobial agents

Abstract

A series of novel 1,2,3-thiadiazoles and 1,2,3-selenadiazoles having a long alkyl chain were synthesized by reacting semicarbazones with SOCl₂ and SeO₂, respectively. The structures of the target compounds 5–12 were confirmed by spectroscopy (IR, ¹H NMR, ¹³C NMR, and MS) and elemental analysis. Their antibacterial and antifungal activities were evaluated against six bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis, Staphylococcus epidermidis, Staphylococcus aureus) and three fungi (Candida albicans, Candida parapsilosis, Candida tropicalis). The results of bioassays indicated that the compounds 5-Dodecyl-4-(4-methoxy-phenyl)-[1-3]selenadiazole (7), 4-Methyl-5-tetradecyl-[1-3]selenadiazole (8) and 5-Dodecyl-4-(4-methoxy-phenyl)-[1-3]thiadiazole (11) displayed moderate antibacterial activity against S. Epidermidis. On the other hand, according to antifungal screening results, compounds 5-Dodecyl-4-phenyl-[1-3]selenadiazole (5), 4-p-Tolyl-5-undecyl-[1-3]selenadiazole (6), and 5-Dodecyl-4-(4-methoxy-phenyl)-[1-3]selenadiazole (7) exhibited significant antifungal activities studied yeast strains.     

Design,synthesis, characterization and biological studies of copper(II) complexes with 2‐aminobenzimidazole derivatives as biomimetic agents

Four novel copper(II) complexes of 2‐aminobenzimidazole derivatives (obtained from the Knoevenagel condensation of acetylacetone (obtained from acetylacetone and halogen‐substituted benzaldehydes) and 2‐aminobenzimidazole) were synthesized. They were characterized using elemental analysis, molar conductance measurements, and fast atom bombardment mass, Fourier transform infrared, NMR, UV–visible and electron paramagnetic resonance spectroscopies. On the basis of the spectral studies, a distorted square planar geometry was assigned for all the complexes. The antibacterial screening of the ligands and their complexes revealed that all the complexes had higher activities than the free ligands. Superoxide dismutase and antioxidant activities of the copper complexes were also studied. The shifts in ΔE _p, E _1/2, I _pc and I _pa values were explored for the interaction of the complexes with calf thymus DNA using the electrochemical technique.