Synthesis,Spectral, Thermal and Biological Studies of Mn(II), Co(II), Ni(II) and Cu(II) Complexes with 1‐(((5‐Mercapto‐1H‐1,2,4‐triazol‐3‐yl)imino)‐methyl)naphthalene‐2‐ol

Mn(II), Co(II), Ni(II) and Cu(II) complexes of 5‐mercapto‐1,2,4‐triazol‐3‐imine‐2′‐hydroxynaphthaline have been synthesized and characterized by elemental analysis, IR, ¹H NMR, EI‐mass, UV‐Vis, and ESR (electron spin resonance) spectra, molar conductance, magnetic moment measurements, DC conductivity and thermogravimetric analysis. IR spectra confirm that the ligand molecule existed in both thione and thiole forms. The molar conductance values indicate the complexes are nonelectrolyte. The magnetic moment values of the complexes display paramagnetic behavior. All studies confirm the formation of an octahedral geometry for complex 1 and the other complexes have tetrahedral geometrical structures. The structures of the complexes have also been theoretically studied by using the molecular mechanic calculations by the hyperchem. 8.03 molecular modeling program which confirm the proposed structures. The Schiff‐base ligand and its metal complexes have also been screened for their antimicrobial activities.     

3‐(2‐(2‐Oxo‐2H‐chromene‐3‐carbonyl)hydrazono)‐N‐(pyridin‐2‐yl)butanamide Complexes: Synthesis,Characterization, DFT,Biological, and Ion‐flotation studies

Schiff base complexes of Cu(II), Ni(II), Cd(II), and Zn(II) with 3‐(2‐(2‐oxo‐2H ‐chromene‐3‐carbonyl)hydrazono)‐N ‐(pyridin‐2‐yl)butanamide (H₂L) were produced. The synthesized compounds were deduced by elemental analysis, molar conductance, magnetic susceptibility, and spectroscopic techniques. The geometry of the prepared complexes was estimated by applying DFT method. Also, Cu(II) and Zn(II) were separated using a simple, quick, and low‐cost quantitative flotation technique preceding to their determinations using atomic absorption spectrophotometric (AAS). Additionally, the biological activities (antimicrobial, antioxidant, and cytotoxic) of isolated compounds were carried out.     

Synthesis and Fungicidal Activity of (1Z, 3Z)‐4,4‐Dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one O‐[2,4‐dimethylthiazole(or 4‐methyl‐1,2,3‐thiadiazole)]‐5‐carbonyl Oximes

A series of novel (Z)‐1‐tert‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐ethanone O‐[2,4‐dimethylthiazole (or 4‐methyl‐1,2,3‐thiadiazole) ?5‐carbonyl] oximes 5a – 5c and (1Z, 3Z)‐4,4‐dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one O‐[2,4‐dimethylthiazole (or 4‐methyl‐1,2,3‐thiadiazole)‐5‐carbonyl] oximes 6a – 6e were synthesized by the condensations of (Z)‐1‐tert‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐ethanone oximes 3 or (1Z, 3Z)‐4,4‐dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one oximes 4 with 2,4‐dimethylthiazole‐5‐carbonyl chloride or 4‐methyl‐1,2,3‐thiadiazole‐5‐carbonyl chloride in the basic condition. Their structures were confirmed by IR, ¹H NMR, mass spectroscopy, and elemental analyses. The results of preliminary bioassays showed the title compounds 5 and 6 exhibited moderate to good fungicidal activities. For example, compound 6c possessed 86.4% inhibition against Fusarium oxysporum, and compound 6b exhibited 86.4 and 100% inhibition against Fusarium oxysporum and Cercospora arachidicola Hori at the concentration of 50 mg/L, respectively.     

Density functional theory/B3LYP study of nanometric 4‐(2,4‐dihydroxy‐5‐formylphen‐1‐ylazo)‐N‐(4‐methylpyrimidin‐2‐yl)benzenesulfonamide complexes: Quantitative structure–activity relationship,docking, spectral and biological investigations

New metal ion complexes were isolated after coupling with 4‐(2,4‐dihydroxy‐5‐formylphen‐1‐ylazo)‐N ‐(4‐methylpyrimidin‐2‐yl)benzenesulfonamide (H₂L) drug ligand. The structural and molecular formulae of drug derivative and its complexes were elucidated using spectral, analytical and theoretical tools. Vibrational spectral data proved that H₂L behaves as a monobasic bidentate ligand through one nitrogen from azo group and ionized hydroxyl oxygen towards all metal ions. UV–visible and magnetic moment measurements indicated that Fe(III), Cr(III), Mn(II) and Ni(II) complexes have octahedral configuration whereas Cd(II), Zn(II) and Co(II) complexes are in tetrahedral form. The Cu(II)complex has square planar geometry as verified through electron spin resonance essential parameters. X‐ray diffraction data indicated the amorphous nature of all compounds with no regular arrangement for the solid constituents during the precipitation process. Transmission electron microscopy images showed homogeneous metal ion distribution on the surface of the complexes with nanometric particles. Coats–Redfern equations were applied for calculating thermo‐kinetic parameters for suitable thermal decomposition stages. Gaussian09 and quantitative structure–activity relationship modelling studies were used to verify the structural and biological features. Docking study using microorganism protein receptors was implemented to throw light on the biological behaviour of the proposed drug. The investigated ligand and metal complexes were screened for their in vitro antimicrobial activities against fungal and bacterial strains. The resulting data indicated that the investigated compounds are highly promising bactericides and fungicides. The antitumour activities of all compounds were evaluated towards human liver carcinoma (HEPG2) cell line.     

Synthesis and Antifungal Activities of ω‐[4‐Aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thio]‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenones

New 4‐aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thiones 3 have been synthesized by the intramolecular cyclization of 4‐aryl‐1‐(1‐phenyl‐5‐methyl‐1,2,4‐triazol‐4‐formyl)thiosemicarbazides 2 with an 8% NaOH solution, and then 3 reacted with ω‐bromo‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenone to afford ω‐[4‐aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thio]‐ω‐(1H‐1,2,4‐triazol‐1‐yl)‐acetophenones 4 . The preliminary biological test showed that the representative compounds possess some anti fungal activities.     

A novel three‐dimensional cadmium(II) coordination polymer incorporating 1,4‐bis­(1,2,4‐triazol‐1‐ylmethyl)­benzene and thio­cyanate

In the title complex, poly[cadmium(II)‐μ₂‐1,4‐bis­(1,2,4‐triazol‐1‐ylmeth­yl)benzene‐di‐μ₂‐thio­cyanato], [Cd(NCS)₂(C₁₂H₁₂N₆)]_n, the Cd^II atom lies on an inversion centre in a distorted octa­hedral environment. Four N atoms from the thio­cyanate and 1,4‐bis­(1,2,4‐triazol‐1‐ylmeth­yl)benzene (bbtz) ligands occupy the equatorial positions, and two S atoms from symmetry‐related thio­cyanate ligands occupy the axial positions. The benzene ring of the bbtz ligand lies about an inversion centre. Single thio­cyanate bridges link the Cd^II atoms into two‐dimensional sheets containing novel 16‐membered [Cd₄(μ‐NCS‐N:S)₄] rings. The bbtz ligands further link these two‐dimensional sheets into an unprecedented covalent three‐dimensional network for the cadmium–thio­cyanate system.     

Synthesis and Fungicidal Activity of 5‐Aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole

A series of novel 5‐aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole 3a – 3n were synthesized by the annulation of 2‐aryloxyacetohydrazides with 3‐aryl‐1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)prop‐2‐en‐1‐ones ( 2 ) in the presence of a catalytic amount of acetic acid. Compounds 2 were obtained by the Knoevenagel reactions of 1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanone ( 1 ) with aromatic aldehydes in the presence of piperidine. Their structures were confirmed by IR, ¹H‐NMR, ESI‐MS, and elemental analyses. The preliminary bioassay indicated that some compounds displayed moderate to excellent fungicidal activity. For example, compounds 3l , 3m , and 3n possessed 100% inhibition against Cercospora arachidicola Hori at the concentration of 50 mg/L.     

Synthesis,Crystal Structure,and Antibacterial Activity of 1,2,4‐Triazoles and 1,2,4‐Triazol‐3‐one

A straightforward method has been developed for the synthesis of 1,2,4‐triazol‐3‐one 3 and 1,2,4‐triazoles 6a , 6b , 6c , 6d starting from N¹‐substituted‐N¹‐tosylhydrazonates 2 and hydrazine monohydrate. This methodology affords a number of 1,2,4‐triazol‐3‐one 3 and 1,2,4‐triazoles 6a , 6b , 6c , 6d in reasonable yields. The structures of all new compounds were elucidated using infrared, ¹H and ¹³C NMR, high‐resolution mass spectrometry, elemental analysis, and the X‐ray crystallography (for compounds 3 and 6a ). Some of the newly synthesized compounds were screened for their antibacterial activity.     

Synthesis and Characterization of Complexes of Copper(II), Nickel(II) and Cobalt(II) with vic-Dioximes Bearing N''-p-Aminobenzoyl Benzaldehyde Hydrazone

Six different arylhydrazone derivatives of p-aminobenzoic hydrazide of vic-dioximes were synthesized by reaction of chloroglyoxime and dichloroglyoxime with N＇-p-aminobenzoyl benzaldehyde, 4-hydroxybenzaldehyde and 4-methoxybenzaldehyde hydrazones, respectively. Metal-ligand （1 ： 2） complexes of vic-dioxime derivatives with Cu（Ⅱ）, Ni（Ⅱ） and Co（Ⅱ） were prepared from corresponding metal acetates. The ligands and their complexes were characterized on the basis of elemental analyses and spectral data. The complexing abilities of these new vic-dioximes toward transition metals of Co（Ⅱ）, Cu（Ⅱ）, Ni（Ⅱ）, Zn（Ⅱ）, Cd（Ⅱ）, Mn（Ⅱ） and Cr（Ⅲ） were determined by solid-liquid extraction studies.     

1,2,4‐Triazol‐3‐ylidenes with an N‐2,4‐Dinitrophenyl Substituent as Strongly π‐Accepting N‐Heterocyclic Carbenes

The synthesis and characterisation of a series of new Rh and Au complexes bearing 1,2,4‐triazol‐3‐ylidenes with a N‐2,4‐dinitrophenyl (N‐DNP) substituent are described. IR, NMR, single‐crystal X‐ray diffraction and computational analyses of the Rh complexes revealed that the N‐heterocyclic carbenes (NHCs) behaved as strong π acceptors and weak σ donors. In particular, a natural bond orbital (NBO) analysis revealed that the contributions of the Rh→C_carbene π backbonding interaction energies (ΔE_bb) to the bond dissociation energies (BDE) of the Rh? C_carbene bond for [RhCl(NHC)(cod)] (cod=1,5‐cyclooctadiene) reached up to 63 %. The Au complex exhibited superior catalytic activity in the intermolecular hydroalkoxylation of cyclohexene with 2‐methoxyethanol. The NBO analysis suggested that the high catalytic activity of the Au^I complex resulted from the enhanced π acidity of the Au atom.     

Green Synthesis of 1‐(1,2,4‐Triazol‐4‐yl)spiro[azetidine‐2,3′‐(3H)indole]‐2′,4′(1′H)‐diones as Potential Insecticidal Agents

One pot green synthesis of 1‐(1,2,4‐triazol‐4‐yl)spiro[azetidine‐2,3′‐(3H)‐indole]‐2′,4′(1′H)‐diones was carried out by the reaction of indole‐2,3‐diones,4‐amino‐4H‐1,2,4‐triazole and acetyl chloride/chloroacetyl chloride in ionic liquid [bmim]PF₆ with/without using a catalyst. It was also prepared by conventional method via Schiff's bases, 3‐[4H‐1,2,4‐triazol‐4‐yl]imino‐indol‐2‐one. Further, the corresponding phenoxy derivatives were obtained by the reaction of chloro group attached to azetidine ring with phenols. The synthesized compounds were characterized by analytical and spectral (IR, ¹H NMR, ¹³C NMR, and FAB mass) data. Evaluation for insecticidal activity against Periplaneta americana exhibited promising results.     

Synthesis and Characterization of Novel 1‐Methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazole Derivatives

A series of novel 1‐methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles was synthesized in three steps from 5‐(1‐methyl‐1H‐indazol‐3‐yl)‐4‐phenyl‐2H‐1,2,4‐triazole‐3(4H)‐thiones. 5‐(1‐Methyl‐1H‐indazol‐3‐yl)‐4‐phenyl‐2H‐1,2,4‐triazole‐3(4H)‐thiones were converted into 1‐methyl‐3‐(5‐(methylsulfonyl)‐4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles upon methylation followed by treatment with aq. KMnO₄. The reaction of 1‐methyl‐3‐(5‐(methylsulfonyl)‐4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles with Raney nickel resulted in desulphonylation to afford corresponding 1‐methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles. All the new synthesized compounds were characterized by spectral techniques.     

Some divalent metal(II) complexes of novel potentially tetradentate Schiff base N,N′‐bis(2‐carboxyphenylimine)‐2,5‐thiophenedicarboxaldhyde: Synthesis,spectroscopic characterization and bioactivities

A novel tetradentate dianionic Schiff base ligand, N ,N ′‐bis(2‐carboxyphenylimine)‐2,5‐thiophenedicarboxaldhyde (H₂L) and some first row d‐transition metal chelates (Co(II), Cu(II), Ni(II) and Zn(II)) were synthesized and characterized using various physicochemical and spectroscopic methods. The spectroscopic data suggested that the parent Schiff base ligand coordinates through both deprotonated carboxylic oxygen and imine nitrogen atoms. The free Schiff base and its metal chelates were screened for their antimicrobial activities for various pathogenic bacteria and fungi using the agar well diffusion method. The antibacterial and antifungal activities of all the newly synthesized compounds are significant compared to the standard drugs ciprofloxacin and nystatin. The antioxidant activities of the compounds were determined by reduction of 1,1‐diphenyl‐2‐picrylhydrazyl and compared with that of vitamin C as a standard. DNA binding ability of the novel Schiff base and its complexes was investigated using absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and thermal denaturation. The obtained results clearly demonstrate that the binding affinity with calf thymus DNA follows the order: Cu(II) complex > Ni(II) complex > Zn(II) complex > Co(II) complex >H₂L. Furthermore, the DNA cleavage activity of the newly synthesized ligand and its metal complexes was investigated using supercoiled plasmid DNA (pUC18) gel electrophoresis.     

Investigation of Mixed Chiral Selectors of Different Metal Ion-L-Alanine Complex and β-Cyclodextrin on the Chiral Separation of Dansyl Amino Acids with Capillary Electrophoresis

Chiral separation of dausyl amino acids by capillary electrophoresis using mixed selectors of Mn(ll)-L-alanine complex and β-cyclodextrin (β-CD) was studied. Resolution was considerably superior to that obtained by using either Mn (Ⅱ)-L-alanine complex or β-CD alone. The effects of separation parameters, such as pH value of buffer solution, capillary temperature, the concentration of Mn (Ⅱ)-L-alanine complex, the types of CD and ligand on the migration times and resolutions were investigated. Six different transition metal complexes,Cu(Ⅱ), Zn(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Hg(Ⅱ) and Cd(Ⅱ)-L-alanine complexes have been employed and compared with Mn(Ⅱ)complex. Differences in retention and selectivity were found.The substitution of Cu(Ⅱ), Zn(Ⅱ), Co(Ⅱ) and Ni(Ⅱ) for Mn(Ⅱ) resulted in a better chiral resolution while Hg(Ⅱ) and Cd(Ⅱ) showed poorer resolution abilities. The chiral separation mechanism was also discussed briefly.     

Metal complexes of novel Schiff base derived from iron sandwiched organometallic and 4‐nitro‐1,2‐phenylenediamine: Synthesis,characterization, DFT studies,antimicrobial activities and molecular docking

The condensation of 2‐acetylferrocene with 4‐nitro‐1,2‐phenylenediamine in a 1:1 molar ratio, resulting in formation of a novel bi‐dentate organometallic Schiff base ligand (L), (2‐(1‐((2‐amino‐5‐nitrophenyl)imino)ethyl)cyclopenta‐2,4‐dien‐1‐yl)(cyclopenta‐2,4‐dien‐1‐yl)iron. Also, its Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes have been synthesized. The stoichiometric ratios of the prepared compounds were estimated using elemental analysis (C, H, N, M), molar conductivity, FT‐IR, UV‐Vis, ¹H‐NMR, SEM and mass spectral analysis. Furthermore, their TG and DTG properties were studied. The geometrical structure of the complexes was found to be octahedral. From spectral analysis, the Schiff base coordinated to metal ions through the azomethine and amine groups. DFT‐based molecular orbital energy calculations of the synthesized ligand have been studied, in which the ligand was theoretically optimized. The Schiff base and its metal complexes have been screened for their antimicrobial activities against different bacterial and fungal species by using disc diffusion method. The anticancer activities of the ligand and its metal complexes have also been studied towards breast cancer (MCF‐7) and human normal melanocytes (HFB‐4) cell lines. Molecular docking was also used to identify the interaction between the Schiff base ligand and its Cd(II) complex with the active site of the receptors of breast cancer mutant oxidoreductase (PDB ID: 3HB5), crystal structure of Staphylococcus aureus (PDB ID: 3Q8U) and yeast‐specific serine/threonine protein phosphatase (PPZ1) of Candida albicans (PDB ID:5JPE).     

A novel two‐dimensional network cadmium(II) coordination polymer containing one 1,4‐bis­(1,2,4‐triazol‐1‐yl)butane and double dicyanamide bridges

In the crystal structure of the title complex, poly[μ‐1,4‐bis­(1,2,4‐triazol‐1‐yl)butane‐di‐μ‐1,5‐dicyanamido‐cadmium(II)], [Cd(C₂N₃)₂(C₈H₁₂N₆)]_n or [Cd(dca)₂(btb)]_n, where dca is dicyanamide and btb is 1,4‐bis­(1,2,4‐triazol‐1‐yl)butane, each Cd^II atom occupies a center of symmetry and is in a six‐coordinated distorted octa­hedral environment. Four N atoms from four dca ligands fill the equatorial positions, and two N atoms from two btb ligands occupy the axial positions. The dca ligands adopt an end‐to‐end coordination mode and link the Cd^II atoms to form a 12‐membered Cd(dca)₂Cd ring, and neighboring rings extend along the b axis to form a [Cd(dca)₂]_n chain. The btb ligands, acting as bridging bidentate ligands, link the Cd^II atoms of adjacent one‐dimensional [Cd(dca)₂]_n chains, forming a rhombic two‐dimensional network.     

Synthesis and pharmacological properties of N‐substituted‐N′‐(4,6‐dimethylpyrimidin‐2‐yl)‐thiourea derivatives and related fused heterocyclic compounds

A series of new N‐Substituted‐N′‐(4,6‐dimethylpyrimidin‐2‐yl)‐thiourea derivatives ( 3a , 3b , 3c , 3d ) and related fused heterocyclic compounds ( 4a , 4b , 4c , 4d ) were synthesized using tetrabutylammonium bromide as phase transfer catalyst (PTC). N‐[(2E)‐5,7‐dimethyl‐2H‐[1,2,4] thiadiazolo [2,3‐a] pyrimidin‐2‐ylidene] derivatives ( 4a , 4b , 4c , 4d ) were prepared by oxidative cyclization of 3a , 3b , 3c , 3d . The structures of these novel compounds were characterized by IR, ¹H NMR, ¹³C NMR, mass spectrometry, and the elemental analysis. The crystal structures were determined from single crystal X‐ray diffraction data. The results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms and showed higher activity against fungi than bacteria. Compounds 3d and 3a exhibited the greatest antimicrobial activity. J. Heterocyclic Chem., 2011.     

Synthesis,characterization, spectroscopic and theoretical studies of transition metal complexes of new nano Schiff base derived from l‐histidine and 2‐acetylferrocene and evaluation of biological and anticancer activities

A new Schiff base derived from the condensation of 2‐acetylferrocene with l ‐histidine was prepared and characterized using elemental analyses and spectroscopic methods. Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of the Schiff base were prepared and characterized using various physicochemical methods such as elemental analysis, Fourier transform infrared and UV–visible spectroscopies, molar conductance, thermal analysis and scanning electron microscopy (SEM). Both ligand and complexes were investigated for their biological and anticancer activities. The elemental analyses showed that complexes were formed in a metal‐to‐ligand ratio of 1:1 stoichiometry. The spectral analyses proved that the ligand was tridentate and all complexes had an octahedral geometry, except the Zn(II) complex that was tetrahedral. SEM showed that the ligand and its Cd(II) complex were of nanometric structure. The molecular and electronic structure of the free ligand was optimized theoretically and the quantum chemical parameters were calculated. The molecular structure can be used to investigate the coordination sites and the total charge density around each atom. According to anticancer studies, Cd(II) complex was recommended to be used as anti‐breast cancer drug as it had very low IC₅₀ (3.5 μg ml^?1). Molecular docking was used to predict the binding between the free ligand and its Cd(II) complex and crystal structure of Staphylococcus aureus (PDB ID: 3Q8u), receptors of breast cancer mutant oxidoreductase (PDB ID: 3Hb5) and crystal structure of Escherichia coli (PDB ID: 3 T88) and to identify the binding mode and the crucial functional groups interacting with the three proteins.     

Synthesis and Characterization of New (Z)‐5‐((1H‐1,2,4‐Triazol‐1‐yl)methyl)‐3‐arylideneindolin‐2‐ones

Ten compounds of new (Z)‐5‐((1H‐1,24‐triazol‐1‐yl)methyl)‐3‐arylideneindolin‐2‐ones ( 5a – j ) have been synthesized by the Knoevenagel condensation of 5‐((1H‐1,2,4‐triazol‐1‐ylmethyl)indolin‐2‐one ( 3 ) with 4‐substituted aromatic aldehydes ( 4a – j ).     

Synthesis,characterization and biocidal studies of new ferrocenyl thiadiazolo‐triazinone complexes

One‐pot synthesis of ferrocenyl ligand, 1,1′‐bis[1,5‐methyl‐4H‐(1,3,4)‐thiadiazolo(2,3‐c)(1,2,4)triazin‐4‐one]ferrocene was prepared from the reaction of 1,1′‐diacetylferrocene with 4‐amino‐2,3‐dihydro‐6‐methyl‐3‐thioxo[1,2,4]triazin‐5(4H)one. The ligand, L, forms 1:1 complexes with Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) in good yield. Characterization of the ligand and its complexes was carried out using IR, ¹H NMR, magnetic susceptibility as well as elemental analysis. Biocidal activity of the ligand and its complexes were determined against the standard fungal strains of Aspergillus niger, Cladosporium herbarum and Fusarium moniliforme using the paper disc diffusion method; and against bacterial strains of Escherichia coli and Staphylococcus aureus using viable cell counting technique. The results indicated that the complexes are biologically more active than the free ligand. The biocidal activity depends on the metal ion, concentration as well as the tested fungi and bacteria. Copyright © 2006 John Wiley & Sons, Ltd.