title: Bay Functionalized Perylenediimide with Pyridine Positional Isomers: NIR Absorption and Selective Colorimetric/Fluorescent Sensing of Fe3+and Al3+Ions.
abstract: Bay functionalized perylene diimide substituted with pyridine isomers, (2-pyridine (2HMP-PDI), 3-pyridine (3-HMP-PDI) and 4-pyridine (4-HMP-PDI)) have been synthesized and explored for selective coloro/fluorimetric sensing of heavy transition metal ions. HMP-PDIs showed strong NIR absorption (760-765 nm) in DMF. The absorption and fluorescence of HMP-PDIs have been tuned by make use of pyridine isomers. Reddish-orange color was observed for 2-HMP-PDI (λmax= 437, 551, 765 nm) whereas 4-HMP-PDI exhibited light green (λmax= 432, 522, 765 nm). 3-HMP-PDI showed orange-yellow (λmax= 431, 524, 762 nm). The fluorescence spectra of 2-, 3- and 4-HMP-PDI showed λmaxat 585, 538, 546 nm, respectively. Interestingly, HMP-PDI dyes showed selective color change (intense pink color) and fluorescence quenching for Fe3+and Al3+metal ions in DMF. Absorbance spectra revealed complete disappearance of NIR absorption and intensification/appearance of new peak at lower wavelength. The concentration dependent studies suggest that 4-HMP-PDI can detect up to 36.52 ppb of Fe3+and 43.12 ppb of Al3+colorimetrically. The interference studies in presence of other metal ions confirmed the good selectivity for Fe3+and Al3+. The mechanistic studies indicate that Lewis acidic character of Fe3+and Al3+ions were responsible for selective color change and fluorescence quenching.
authors.affiliation: School of Chemical & Biotechnology, SASTRA University, Thanjavur, Tamil Nadu, 613401, India.
authors.forename: Anu
authors.initials: A
authors.lastname: Kundu
authors.affiliation: Department of Chemistry, Karunya University, Coimbatore, Tamil Nadu, 641 114, India.
authors.forename: Jayaraman
authors.initials: J
authors.lastname: Pitchaimani
authors.affiliation: Department of Chemistry, Karunya University, Coimbatore, Tamil Nadu, 641 114, India. madhu@karunya.edu.
authors.forename: Vedichi
authors.identifier: http://orcid.org/0000-0003-0253-6864
authors.initials: V
authors.lastname: Madhu
authors.affiliation: Materials Chemistry Division, School of Advanced Science, VIT University, Vellore, 632014, India.
authors.forename: Pachagounder
authors.initials: P
authors.lastname: Sakthivel
authors.affiliation: Materials Chemistry Division, School of Advanced Science, VIT University, Vellore, 632014, India.
authors.forename: Ramasamy
authors.initials: R
authors.lastname: Ganesamoorthy
authors.affiliation: School of Chemical & Biotechnology, SASTRA University, Thanjavur, Tamil Nadu, 613401, India. philip@biotech.sastra.edu.
authors.forename: Savarimuthu Philip
authors.initials: SP
authors.lastname: Anthony
keywords: Bay functionalized perylenediimide; NIR absorption; Pyridine positional isomers; Selective colorimetric/fluorescent sensing of Fe3+ and Al3+ ions