Synthesis of a novel N,N',N'-tetraacetyl-4,6-dimethoxyindole-based dual chemosensor for the recognition of Fe3+ and Cu2+ ions

• Published in: Inorganica Chimica Acta Vol. 495; p. 118947
• Main Authors: Şenkuytu, Elif, Bingul, Murat, Saglam, Mehmet F., Kandemir, Hakan, Sengul, Ibrahim F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2019; Elsevier Science Ltd
• Subjects: Aluminum; Binding sites; Calcium ions; Cations; Chemical sensors; Chemical synthesis; Chemoreceptors; Chemosensors; Cobalt; Colorimetry; Copper; Cupric ions; Dimethylformamide; Ferric ions; Fluorescence; Indole; Iron; Manganese; Mass spectrometry; NMR; Nuclear magnetic resonance; Recognition; Single crystals; Stoichiometry; Triethylamine; Fluorescence; Iron; Copper; Indole; Chemosensors
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2019.05.046

[Display omitted] •Synthesis and characterizations of a novel N,N',N'-tetraacetyl-4,6-dimethoxyindole is presented.•Single crystals were grown and whose structure was analysed.•The photophysical properties and metal sensing behaviour of new dimethoxyindole were also examined.•The indole ligand system displayed an exclusive selectivity and sensitivity response toward both Cu+2 and Fe3+. A novel N,N',N',1-tetraacetyl-4,6-dimethoxy-1H-indole-2-carbohydrazide 5, bearing four N-acetyl groups (N-COCH3) as cation binding sites was successfully synthesized by the reaction of readily available 4,6-dimethoxy-1H-indole-2-carbohydrazide 4 with acetic anhydride in dimethyl formamide in the presence of triethylamine. The structure of the acetyl indole 5 was confirmed using 1H NMR, 13C NMR, FT-IR, mass spectrometry and single crystal X-ray diffraction techniques. The colorimetric sensing ability of targeted compound 5 was investigated by monitoring UV–Vis and fluorescence spectroscopy spectral changes upon addition of different cations. The compound 5 demonstrated selective recognition toward the Fe+3 and Cu+2 ions over other cations examined such as Li+, Na+, K+, Mg2+, Ca2+, Ba2+, Mn2+, Fe2+, Cr3+, Co2+, Ni2+, Ag+, Cd2+, Al3+, Hg+, Zn2+. The complex stoichiometry of the compound 5 and Cu2+/Fe3+ ions were determined as 2:1 (ligand/metal) by fluorescence titrations (Job's plot). This is the first report showing 4,6-dimethoxyindole moiety represents a dual chemosensor capable of detecting the Cu2+ and Fe3+ ions.