APPLIED ORGANOMETALLIC CHEMISTRY Appl. Organometal. Chem. 2006; 20: 505–511 Published online 22 June 2006 in Wiley InterScience (www.interscience.wiley.com) DOI:10.1002/aoc.1100 Materials, Nanoscience and Catalysis Synthesis, characterization and biocidal studies of new ferrocenyl thiadiazolo-triazinone complexes Said M. El-shiekh 1 , Mokhles M. Abd-Elzaher 2 * and Mohamed Eweis 3 1 Nanomaterials Laboratory, Advanced Materials Department, Central Metallurgical Research and Development Institute, CMRDI, PO Box 87, Helwan 11421, Cairo, Egypt 2 Inorganic Chemistry Department, National Research Centre, PO 12622 Dokki, Cairo, Egypt 3 Department of Botany, Faculty of Science, Cairo University, Cairo, Egypt Received 30 March 2006; Revised 21 April 2006; Accepted 26 April 2006 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, 1 H 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. KEYWORDS: diacetylferrocene; thiadiazolo-triazinone; magnetic properties; biocidal activity INTRODUCTION Ferrocene compounds are characterized by their ability to make metal-centred redox systems, so they have wide appli- cations in various fields such as molecular recognition as sensors and biosensors, 1,2 in homogenous and asymmetric catalysis, 3–5 in polymer science as red-ox active polymers and dendrimers, 6 in synthesis of photochemical complexes 7 or in the design of new nonlinear optical materials, 8,9 new materi- als such as liquid crystals 10 and supramolecular chemistry. 11 Ferrocene is often incorporated into some organic molecules in order to obtain newly compounds which have higher bio- logical activity due to unique structure, different membrane- permeation properties and anomalous metabolism. 12,13 A successful example is the application of platinum ferrocene complexes as antitumour agents. 14 Therefore, ferrocene compounds, such as ferrocifen 15 – 18 and 7-chloro-4[2-(N ′ ,N ′ - dimethylaminomethyl)-N-ferrocenyl-methylamino]quino- *Correspondence to: Mokhles M. Abd-Elzaher, Inorganic Chemistry Department, National Research Centre, PO 12622 Dokki, Cairo, Egypt. E-mail: mokhlesm20@yahoo.com line, 19 – 21 have good activities as medicals and chemotherapy agents. On the other hand, several reports have indicated that (1,3,4)thiadiazolo(2,3-c)(1,2,4)triazin-4-one derivatives have significant biological activities against Aspergillus niger and Fusarium oxysporium. 22 – 24 It was found also that some thiadiazole derivatives have wide applications as antitumour agents, pesticides, dyes lubricants, herbicides and analytical reagents. 25 – 27 In continuation of our previous studies, 28 – 30 a new ligand has been 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 has high potential to react with var- ious ions to form stable complexes. Therefore, the aim of the article was extended to prepare and characterize the Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes with the mentioned ligand in order to obtain the heterobimetallic complexes. The prepared ligand and its complexes have been characterized by IR and 1 H NMR spectra as well as elemental analysis and magnetic susceptibility. These compounds were evaluated for their biocidal activity against Aspergillus niger, Cladosporium herbarum, Fusarium moniliforme, Escherichia coli and Staphylococcus aureus. Copyright  2006 John Wiley & Sons, Ltd.