Turning On MLCT Phosphorescence of Iridium(III)–Borane Conjugates upon Fluoride Binding

Abstract

The heteroleptic complexes (C ∧ N) 2 Ir III (C ∧ N: ppy, 2; btp, 3), bearing a 4-(dimesitylboryl)benzoate (Bbz) auxiliary ligand, and their fluoride adducts were prepared and characterized. While the PL spectra of 2 and 3 exhibit very weak emission in solution, the addition of fluoride turned on (C ∧ N) 2 Ir-centered phosphorescence (λ em 527 nm for 2 and 617 nm for 3). Experimental and DFT calculations suggest that the weak emission is ascribable to a photoinduced electron transfer from the MLCT state of the (C ∧ N) 2 Ir moiety to the Bbz ligand and is switched on by fluoride binding to the boron center of the Bbz ligand.

A highly selective ratiometric detection of F−based on excited-state intramolecular proton-transfer (imidazole) materials

“…7,8 Hence, the regulation and detection of uoride attracted considerable attention. Over the past decade a number of uoride ion sensors based on different signaling mechanisms, such as intramolecular charge transfer, 9,11,12 photo-induced electron transfer, [13][14][15][16][17][18][19][20][21][22] uorescence resonance energy transfer, [23][24][25][26][27] twisted intramolecular charge transfer, 28,29 excited state proton transfer, [30][31][32][33][34][35][36][37][38][39][40][41] metal-ligand charge transfer, [42][43][44][45][46] and excimer/exciplex [47][48][49] formation, have been used. However most of the reported probes suffer from low sensitivity (or) slow response, turn-off uorescence response and complicated synthetic procedures.…”

Synthesis and characterization of poly(tetraphenylimidazole)s and their application in the detection of fluoride ions

“…The development of selective and efficient sensors is of prime importance owing to their applications in biological, and analytical processes. 1-8 A number of sensors or probes have been reported for the detection of different analytes based on intramolecular charge transfer, 9,10 photoinduced electron transfer, [11][12][13][14][15] uorescence resonance energy transfer, [16][17][18][19][20] excimer/exciplex formation, [21][22][23] metal-ligand charge transfer, [24][25][26][27] and twisted intramolecular transfer. 28 Another unique process known as excited state intramolecular proton transfer (ESIPT) has given promising materials with applications ranging from organic light emitting diodes to uorescent probes.…”

Chalcone Based Colorimetric Sensor for Anions: Experimental and TD-DFT Study

“…Most of the sensor-anion interactions are based on hydrogen bonding interaction and some of them are followed by sensor deprotonation [4][5][6]. Furthermore, the chemosensor sensing mechanisms have been suggested as intramolecular charge transfer (ICT) [7], photoinduced electron transfer (PET) [8], excited states proton transfer (ESPT) [9], and metal-ligand charge transfer (MLCT) [10]. Chalcone derivative, 3-(4-hydroxy-3-methoxy phenyl)-1-phenyl-2-propen-1-one (1), is promising candidate for anion chemosensor because of its ability for proton donating in hydrogen bonding interaction and its conjugation system through phenol ring and enone group [11][12].…”