Development of Rhodamine 6G-Based Fluorescent Chemosensors for Al³⁺-Ion Detection: Effect of Ring Strain and Substituent in Enhancing Its Sensing Performance

Abstract

Four rhodamine 6G-based chemosensors (H 3 L1–H 3 L4) are designed for selective detection of Al3+ ion. They are characterized using various spectroscopic techniques and X-ray crystallography. All absorption and emission spectral studies have been performed in 10 mM N-(2-hydroxyethyl)­piperazine-N′-ethanesulfonic acid (HEPES) buffer solution at pH 7.4 in H2O/MeOH (9:1, v/v) at 25 °C. In absorption spectra, chemosensors exhibit an intense band around 530 nm in the presence of Al3+ ion. Chemosensors (H 3 L1–H 3 L4) are nonfluorescent when excited around 490 nm. The presence of Al3+ ion enhances the emission intensity (555 nm) many times. The formation of complexes 1–4 is established with the aid of different spectroscopic techniques. The limit of detection value obtained in the nanomolar range confirms the high sensitivity of the probes toward Al3+ ion. It has been observed that the presence of aliphatic spacers in the diamine part and different halogen substituents in the salicylaldehyde part strongly influences the selectivity of the chemosensors toward Al3+ ion. The propensity of the chemosensors to identify intracellular Al3+ ions in triple-negative human breast cancer cell line MDA-MB-468 by fluorescence imaging is also examined in this study.

A Highly Selective “Turn‐On” Fluorescent Sensor for Aluminum Ion Detection in Aqueous Solution Based on Imidazo[2,1‐b]thiazole Schiff Base

“…[5] Recently, fluorescent chemosensors for detection of biologically or environmentally important ions have drawn general interest comparing to traditional methods duo to their advantages of high sensitivity, high selectivity, fast response time, simple manipulation, easy visualization and bioimaging capability. [6] Over the past few years, various fluorescent chemosensors including hydrazide, [3c] phenolphthalein, [4] naphthyl, [6a] thiophene, [7] coumarin, [8] naphthalimide, [9] rhodamine, [10] and BODIPY [11] were designed for detection of Al 3 + . However, most of the reported fluorescent sensors could only work in organic solvents, [12] which severely limits their potential application in environmental and biological systems.…”

“…Over the past few years, various fluorescent chemosensors including hydrazide, [3c] phenolphthalein, [4] naphthyl, [6a] thiophene, [7] coumarin, [8] naphthalimide, [9] rhodamine, [10] and BODIPY [11] were designed for detection of Al 3+ . However, most of the reported fluorescent sensors could only work in organic solvents, [12] which severely limits their potential application in environmental and biological systems.…”

Recent Progress in Small Spirocyclic, Xanthene-Based Fluorescent Probes

“…The final section will summarize recent advances in the synthesis and understanding of their structure including novel computational approaches. Even though a lot of progress has been achieved, pH-sensing [60][61][62][63][64], metal ion detection [65][66][67][68][69][70][71][72], and the use of Spirocyclic, xanthene-based probes usually have a hydroxy-or carboxy-moiety or other intramolecular nucleophiles at the 2 position of a pendant aromatic ring at the C-9 -atom of the xanthene core (Scheme 1) [41,42]. This intramolecular nucleophilic-moiety attacks the sp 2 -hybridized C-9 -atom and forms the colorless spirocyclic form.…”

“…The final section will summarize recent advances in the synthesis and understanding of their structure including novel computational approaches. Even though a lot of progress has been achieved, pH-sensing [ 60 , 61 , 62 , 63 , 64 ], metal ion detection [ 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ], and the use of nanoparticles [ 21 , 73 , 74 , 75 , 76 , 77 , 78 ] or any other solid support [ 79 , 80 , 81 , 82 ] will be omitted, given the scope of this review.…”

Multifunctional rhodamine B appended ROMP derived fluorescent probe detects Al3+ and selectively labels lysosomes in live cells

“…In this respect, and due to the potential impact of Al 3+ on human health and the environment, it is of considerable importance to develop new fluorescent sensor probes. To date, most of the reported Al 3+ probes developed are based on small organic molecules [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] , carbon dots [26][27][28] , MOFs 7,29 , and transition metal complexes 30,31 . However, many of such systems suffer from achieving specificity either due to the interference of other transition metal ions 4,9,32,33 or weak coordination and strong hydration ability (enthalpies of hydration is − 4680 kJ/mol) character.…”