Highly selective CHEF-type chemosensor for lutetium (III) recognition in semi-aqueous media

R Selva Kumar; S K Ashok Kumar; Kari Vijayakrishna; Akell Sivaramakrishna; C V S Brahmnanda Rao; N Sivaraman; Suban K Sahoo

doi:10.1016/j.saa.2019.02.003

Highly selective CHEF-type chemosensor for lutetium (III) recognition in semi-aqueous media

Spectrochim Acta A Mol Biomol Spectrosc. 2019 May 5:214:32-39. doi: 10.1016/j.saa.2019.02.003. Epub 2019 Feb 5.

Authors

R Selva Kumar¹, S K Ashok Kumar², Kari Vijayakrishna¹, Akell Sivaramakrishna¹, C V S Brahmnanda Rao³, N Sivaraman³, Suban K Sahoo⁴

Affiliations

¹ Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India.
² Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India. Electronic address: ashok312002@gmail.com.
³ Indira Gandhi Centre for Atomic Research, Homi Bhabha National Institute (HNBI), Kalpakkam 603102, Tamil Nadu, India.
⁴ Department of Applied Chemistry, S. V. National Institute Technology, Surat 395007, Gujarat, India.

PMID: 30763916
DOI: 10.1016/j.saa.2019.02.003

Abstract

A simple phosphoryl quinolone (L) based sensor has been synthesized for the selective recognition of Lu³⁺ by spectrofluorimetric method. In methanol-water (1:1, v/v), the ligand L exhibits a weak emission peak at 400 nm upon excitation at 280 nm. Upon interaction with various f-metal and other selected metals from s, p, and d-block elements, the fluorescence of L is selectively enhanced in the presence of Lu³⁺ due to the chelation enhanced fluorescence (CHEF) effects. The quantum yield (φ) of L (φ = 0.063) is enhanced to φ = 0.118 upon chelation with Lu³⁺ ion. From the titration experiment, the limit of detection (LOD) of sensor L to recognize Lu³⁺ is estimated down to 24.2 nM, which is much lower than the WHO guidelines (76 μM) in drinking water. The formation of host-guest complexation between L and Lu³⁺ in 2:1 binding stoichiometry is studied by Job's method and the binding constant is estimated by band fit analysis (logK_f = 5.1). Further, the coordination behaviour between L and Lu³⁺ is well supported by FT-IR, ¹H NMR, ¹³C NMR, ³¹P NMR, ESI mass spectral data and the theoretical results.

Keywords: AIE; CHEF; DFT; Fluorescent chemosensors; Lu(3+).