Borylated Arylisoquinolines: Photophysical Properties and Switching Behavior of Promising Tunable Fluorophores

A series of blue-emissive 7-(diphenylamino)-4-phenoxycoumarin derivatives bearing -CF , -OMe, or -N(Me) substituents on the phenoxy subunit were synthesized. Although both the -CF and -N(Me) modifications were found to trigger redshifted fluorescence, the -OMe substitution was demonstrated to exert an unexpected blueshift color-tuning effect toward the deep-blue region. The reason is that the moderate electron-donating -OMe group can endow coumarins with unaltered HOMO but elevated LUMO energy levels. Moreover, the -OMe substitution was found to be beneficial to the thermal stability of these coumarins. Therefore, the trimethoxy-substituted objective compound can act as a high-performance deep-blue organic light-emitting diode (OLED) emitter, and OLED based on it emits deep-blue light with CIE coordinates of (0.148, 0.084), maximum luminance of 7800 cd m , and maximum external quantum efficiency of 5.1 %. These results not only shed light on the molecular design strategy for high-performance deep-blue OLED emitters through color-tuning, but also show the perspective of coumarin derivatives as deep-blue OLED emitters.

Section: Figurecontrasting

confidence: 63%

Acquiring High‐Performance Deep‐Blue OLED Emitters through an Unexpected Blueshift Color‐Tuning Effect Induced by Electron‐Donating ‐OMe Substituents

Peng

Zhao

et al. 2018

“…However, we believe that this is unlikely in practice as the energy difference is quite high (Δ G =5.7 kcal mol −1 ), favoring the structure in which B–N coordination is preserved. The underlying structure‐property relationships appear rather complex as boronic esters in this class can show fluorescence with highly variable quantum yields …”

Section: Resultsmentioning

confidence: 99%

“…The underlying structure-property relationships appearr ather complex as boronic esters in this class can show fluorescencew ith highly variable quantum yields. [29] TuningBOBIPYs for bioapplications…”

Section: Stability Studiesmentioning

confidence: 99%

A Modular Class of Fluorescent Difluoroboranes: Synthesis, Structure, Optical Properties, Theoretical Calculations and Applications for Biological Imaging

Bachollet

Volz

Fiser

et al. 2016

Ten borylated bipyridines (BOBIPYs) have been synthesized and selected structural modifications have been made that allow useful structure-optical property relationships to be gathered. These systems have been further investigated using DFT calculations and spectroscopic measurements, showing blue to green fluorescence with quantum yields up to 41%. They allow full mapping of the structure to determine where selected functionalities can be implemented, to tune the optical properties or to incorporate linking groups. The best derivative was thus functionalised with an alkyne linker, which would enable further applications through click chemistry and in this optic, the stability of the fluorophores has been evaluated.

“…This was motivated by our earlier studies of arylisoquinoline boronic esters (BAI dyes) whose fluorescence properties can be conveniently controlled by the variation of electronic properties of substituents, protonation or temperature. [25][26][27] The herein investigated N,C chelates (see structures in Scheme 1) feature a higher -conjugation than the abovementioned photochromic B(ppy)Mes2 compounds. [23] In addition they contain electrondonating substituents and the electron-accepting isoquinolinyl moiety.…”

Section: Introductionmentioning

confidence: 87%

Strongly Emissive and Photostable Four‐Coordinate Organoboron N,C Chelates and Their Use in Fluorescence Microscopy

Pais

Alcaide

López‐Rodríguez

et al. 2015

Self Cite

112

Six strongly fluorescent four-coordinate organoboron N,Cchelates, containing an arylisoquinoline skeleton, were prepared. Remarkably, the fluorescence quantum yields reach values of up to 0.74 in oxygen-free toluene. The strong B-N interaction was corroborated by the single-crystal X-ray analysis of two dyes. The intramolecular charge-transfer (ICT) character of the fluorophores was evidenced by solvatochromic studies and time-dependent density-functional-theory calculations at the PCM(toluene)/CAM-B3LYP/6-311++G(2d,p)//PCM(toluene)/B3LYP/6-311G(2d,p) level of theory. The compounds combine high chemical stability with high photostability (especially when equipped with electron-donating substituents). The strong fluorescence and the large Stokes shifts predestine these compounds for their use in confocal fluorescence microscopy. This was demonstrated for the imaging of the N13 mouse microgial cell line. As a surplus, significant two-photon absorption cross sections (up to 61 GM) allow the use of excitation wavelengths in the near-infrared region (> 800 nm).