A near-infrared phosphorescent probe for F− based on a cationic iridium(III) complex with triarylboron moieties

Abstract

In this work, a near-infrared (NIR) phosphorescent probe for F  based on a cationic Ir(III) complex [Ir(Bpq) 2 (quqo)]PF 6 (1) with dimesitylboryl (Mes 2 B) groups on the cyclometalated C^N ligands (Bpq) and 2-(quinolin-2-yl)quinoxaline (quqo) as N^N ligand was designed and synthesized. The excited state properties of 1 were investigated in detail using molecular orbital calculations and experimental methods. Upon excitation, complex 1 shows NIR phosphorescent emission around 680 nm. Interestingly, the complex can be excited with long wavelength around 610 nm. Such long-wavelength excitation can reduce the background emission interference and improve the signal-to-noise ratio. Furthermore, the selective binding between boron atom and F  can give rise to the quenching of emission and realize the near-infrared phosphorescent sensing for F  . We wish that the results reported herein will be helpful for the further design of excellent near-infrared phosphorescent probes based on heavy-metal complexes.

Functionalized Quinoxaline for Chromogenic and Fluorogenic Anion Sensing

“…Xu et al [54] designed an ovel NIR-emitting cationic Ir III complex with CN ligandsc ontaining dimesitylboryl groups and an extended NN ligand, 28-Ir III (Figure 23). Upon photoexcitation, the complex shows NIR phosphorescent emissiona round 680 nm.…”

“…Xu et al . designed a novel NIR‐emitting cationic Ir III complex with CN ligands containing dimesitylboryl groups and an extended NN ligand, 28‐Ir III (Figure ).…”

Room temperature phosphorescence from natural products: Crystallization matters

“…The essential differences between fluorescence and phosphorescence are the degeneracy of the excited states, the far longer lifetimes of triplets versus singlets, and the sensitivities of triplets to a wider variety of quenching conditions. Such differences endow phosphorescent materials unique photophysical properties and advantages in a number of potential applications, for examples, organic light emitting diodes [1,2], photovoltaic devices [3,4], sensors [5,6] and bioimaging [7,8]. However, so far phosphorescent luminogens are essentially inorganic and organometallic compounds because metals could promote spin-orbit coupling.…”

Boron‐Functionalized Phosphorescent Iridium(III) Complexes

“…This showed a near-infrared (NIR) phosphorescent emission (Table 1), and selective B-F binding could also quench the emission and produce a NIR phosphorescence response to F -. [24] Ratiometric detection measures the luminescence intensity ratio changes at two different wavelengths, which can increase the sensitivity and minimize external and environmental influences. The two ratiometric F -chemical sensors 13 and 14, with Bpq as the cyclometalated C^N ligands (Scheme 2) and based on Ir III complexes with conjugated and nonconjugated D-A structures, respectively, were synthesized, and their photophysical properties were investigated.…”