A Novel Rhodamine-Benzimidazole Conjugate as a Highly Selective Turn-on Fluorescent Probe for Fe3+

Abstract

In this manuscript, a novel probe RHBI based on the rhodamine-benzimidazole conjugate was designed and synthesized. RHBI showed an extreme selectivity for Fe(3+) over other metal ions such as Pb(2+), Ni(2+), Co(2+), Mn(2+), Zn(2+), Hg(2+), Cd(2+), Ag(+), Mg(2+), Ca(2+), Ba(2+), Na(+) and K(+) in acetonitrile. Upon the addition of 10 equiv. of Fe(3+), a 1098-fold fluorescence intensity enhancement was observed at the maximum emission wavelength of 582 nm. Both the Job's plot and ESI-MS showed that RHBI coordinated with Fe(3+) in a 1:1 stoichomitry and the calculated binding constant was 1.01 × 10(4) M(-1). The competition experiment for Fe(3+) ions mixed with other metal ions exhibited no obvious change except Cu(2+) that could induce a mild fluorescence quenching. Moreover, the fluorescence emission increased linearly with the Fe(3+) concentration in the range of 6 × 10(-6)-4 × 10(-5) M and the detection limit was 1.5 × 10(-8) M.

Bis-Benzimidazolyl Diamide Based Fluorescent Probe for Copper(II): Synthesis, Structural and Fluorescence Studies

“…No such behavior was figure S8). The binding constant is found to be smaller than those reported with other ligating system [10,53].…”

“…A large numbers of new fluorescent probes that detect transition metal ions in solution have been reported [4][5][6][7][8][9][10][11][12][13][14][15]. A new area where organic molecules are utilized to act as sensors, switches, triggers and logic gates has developed rapidly.…”

A Novel Chemosensor Based on Rhodamine Derivative for Colorimetric and Fluorometric Detection of Cu2+ in Aqueous Solution

“…Besides, rhodamine derivatives are well-known for their spirolactam (fluorescence "off") to ring-opened amide (fluorescence "on") equilibrium, during which significant fluorescence enhancement as well as color changes will take place, and based on this mechanism, a variety of rhodamine-based spirolactam derivatives have been designed as probes for the recognition of different metal ions such as Pb 2+ [16,17], Hg 2+ [18][19][20], Cu 2+ [21][22][23][24], Fe 3+ [25][26][27], Cr 3+ [28,29].…”

A nanostructured LUS-1 based organic–inorganic hybrid optical sensor for highly selective sensing of Fe3+ in water

“…Up to now, various molecular sensors have been successfully developed for the detection of low-level of Fe 3 þ ions [16][17][18][19][20][21][22], however, many of these sensors suffer from some disadvantages including interference problems caused by other transition metal cations such as Cr 3 þ [23][24][25][26] and Cu 2 þ [27] and poor direct applicability in 100% aqueous solution [28,29]. Therefore, there is room for introducing a novel hybrid optical sensor to overcome these drawbacks.…”