NNS tridentate thiosemicarbazide and 1,3,4-thiadiazole-2-amine complexes of some transition metal ions: syntheses,structure and fluorescence properties |
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| Authors: | A Bharti Pooja Bharati NK Singh |
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| Institution: | 1. Department of Chemistry, Banaras Hindu University, Varanasi, India;2. Department of Chemistry, Kirori Mal College, University of Delhi, Delhi, India |
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| Abstract: | The reactions of Zn(II), Mn(II), and Ni(II) acetates with 1-picolinoyl-4-phenyl-3-thiosemicarbazide (Hppts) yielded Zn(ppts)2]·CHCl3 (3), Mn(ppts)2]·THF (4), and Ni(ppts)2]·THF (5), respectively, but HgCl2 gave a cyclized product N-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole-2-yl-amine (2). The treatment of Hppts with conc. H2SO4 formed N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-yl-amine (1). Hppts is a nonfluorescent material, but 3, 4 and the cyclized products 1,3,4-oxadiazole/1,3,4-thiadiazole are fluorescent. The cyclized ligand N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-amine (1) formed Zn(2-Hppt)2(OAc)2] (6) and Cd2(2-Hppt)2(OAc)2(μ-OAc)2] (7) in which Cd(II) has a binuclear acetate-bridged seven coordinate pentagonal bipyramidal geometry. Complex 7 is also a fluorescent material with maximum emission at 425 nm at an excitation wavelength of 254 nm. |
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| Keywords: | NNS tridentate thiosemicarbazide thiadiazole complexes Zn(II) complexes fluorescence properties |
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