A New Highly Selective, Ratiometric and Colorimetric Fluorescence Sensor for Cu²⁺ with a Remarkable Red Shift in Absorption and Emission Spectra Based on Internal Charge Transfer

Abstract

A new 1,8-diaminonaphthalene based ratiometric and highly selective colorimetric "off-on" type of fluorescent probe, receptor 2 has been designed and synthesized that senses only Cu(2+) among the other heavy and transition metal ions examined on the basis of internal charge transfer (ICT). The visual sensitivity of the receptor 2 is remarkable, showing dual color changes from colorless (receptor) to purple followed by blue and a large red shift in emission upon Cu(2+) complexation.

A novel system for Fe3+ ion detection based on fluorescence resonance energy transfer

“…6). While the absorption intensity of donor gradually increased, the absorption peak of acceptor showed bathochromic shift with increasing Fe 3+ ion concentration [28,29].…”

Thiophene aldehyde-diamino uracil Schiff base: A novel fluorescent probe for detection and quantification of cupric, silver and ferric ions

“…Copper ion fluorescent sensors include heptamethine cyanine-based near-infrared fluorescent probe [17], dansyl-based probe [18], 6-(N,N-dimethylamino)-2-naphthoylacryl acid [19], triarylpyrazoline-based Cu(I) sensor [20], coumarin Schiff base [21], near-infrared fluorescent probe based on photo-induced electron transfer mechanism [22], bis-benzimidazolyldiamide-based probe [23], riboflavin-stabilized gold nanoclusters [24], [3-diam inophenazine, 1,2-diamino-anthraquinone and 2,4-dinitrophen ylhydrazine] [25], coumarin-based sensor [26,27], dehydroabietyl derivative bearing a 2-(2 0 -hydroxyphenyl) benzimidazole unit [28], rhodamine B hydrazide hydrazone derivative [29], carboxylic acid-functionalized tris(2,2 0 -bipyridine)-ruthenium(II) complex [30], thiourea-based probe [31], carbazole-based Schiff base [32], rhodamine-based probe [33], silver nanoclusters (Ag NCs) [34], 1,8-diaminonaphthalene-based sensor [35] and malonamide fluoroionophore [36].…”

Spectroscopic (FT-IR, 1H, 13C NMR, UV), DOS and orbital overlap population analysis of copper complex of (E)-4-(2-(4-nitrophenyl) diazenyl)-N, N bis ((pyridin-2-yl) methyl) benzamine by density functional theory

“…To overcome these difficulties many chemo sensors techniques have been developed and reported in the literature [5][6][7]. Out of these techniques, calorimetric techniques have many advantages like they are convenient to examine with naked eyes [8]. The title compound shows experimentally well proven sensing properties for selective detection of Cu2 + ions based on azobenzene as signaling unit [9].…”