Synthesis, characterization, structural analysis of metal(II) complexes of N'-[(E)-3-Bromo-5-Chloro-2-hydroxybenzidene]-4-hydroxybenzohydrazide-Multisubstituted Schiff base as a F(-) and Cu(2+) ions selective chemosensor.
New colorimetric chemosensor, N'-[(E)-3-Bromo-5-Chloro-2-hydroxybenzidene]-4-hydroxybenzohydrazide, containing OH and NH groups as binding sites have been synthesized and characterized by spectral UV, IR, NMR and ESR. The molecular structure of ligand is determined by X-ray crystallography and it has the monoclinic space group P21/c with cell parameters a=15.1058(6), b=14.3433(6), c=17.5800(8)Å and Z=8. The electronic spectral measurements show that Co(2+), Ni(2+) and Zn(2+) complexes have tetrahedral geometry, while Cu(2+) complex has square planar geometry. Magnetic measurements show that Cu(2+), Co(2+) and Ni(2+) complexes have paramagnetic behavior and Zn(2+) complex has diamagnetic behavior. Anion binding studies carried out using (1)H NMR and UV-visible spectrophotometric titrations revealed that these receptors exhibit selective recognition towards F(-) over other halide anions. The selectivity for F(-) among the halides is attributed mainly to the hydrogen-bond interaction of the receptor with F(-). Receptor (5 × 10(-5)M) shows color change from colorless to yellow in the presence of tetrabutylammonium fluoride (TBAF, 1.5 × 10(-3)M). Moreover, F(-)-induced color changes remain the same even in the presence of large excess of Cl(-), Br(-) and I(-). The binding constant is found to be higher towards F(-) ion and this may be due to presence of OH group, which offers extra binding site. Chromogenic receptor undergoes distinct color changes from colorless to green on gradual addition of Cu(2+) can be used as colorimetric probes for spectrophotometric and visual analysis of Cu(2+) in the presence of other transition metal ions such as Co(2+), Ni(2+) and Zn(2+).
Department of Chemistry, Madras Medical College, Chennai 600 003, India.
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Sundar
Department of Chemistry, Government Arts College (Men), Nandanam, Chennai 600 036, India.
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Prabhu
PG & Research Department of Chemistry, Presidency College (Autonomous), Chennai 600 005, India.
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Indra Gandhi
Department of Chemistry, Government Arts College (Men), Nandanam, Chennai 600 036, India. Electronic address: mmarappan@yahoo.com.
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Marappan
Department of Chemistry, Madras Medical College, Chennai 600 003, India; Department of Chemistry, Government Arts College, Melur, Madurai 625 106, India. Electronic address: rajagopal18@yahoo.com.
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Rajagopal
D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000032:analysis*; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D005461:Fluorine / Q000032:analysis*; D062385:Hydroxybenzoates / Q000737:chemistry*; D007477:Ions / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D012545:Schiff Bases / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet
D056831:Coordination Complexes; D062385:Hydroxybenzoates; D007477:Ions; D012545:Schiff Bases; D005461:Fluorine; C002429:4-hydroxybenzoic acid hydrazide; D003300:Copper
Cation sensor; Chemosensor; Colorimetric; Fluoride sensor; Hydrazones; X-ray analyses