6-(Arylvinylene)-3-bromopyridine derivatives as lego building blocks for liquid crystal, nonlinear optical, and blue light emitting chromophores
Abstract
A novel general synthetic strategy, based on a convergent approach, allowed us to prepare a series of conjugated 6,6′-distyryl-3,3′-bipyridine derivatives via the Suzuki reaction. First, the key electron-donor and electron-acceptor 6-(arylvinylene)-3-bromopyridine building blocks were synthesized by Knoevenagel-or Siegrist-type reactions. Second, some of them were transformed to the corresponding pyridylboronic esters. Finally, for the first time, we successfully demonstrated that such blocks can be homo- and cross-coupled in high yields and multigram scales, leading to noncentrosymmetic or symmetric chromophores. Their mesogenic, electrochemical, and optical properties have been investigated depending on the electronic structure. In this series, push-pull compounds are liquid crystals and promising for NLO applications. Whatever the structure, all of these compounds exhibit a high electron affinity and are strongly fluorescent. As an application, lasing properties of one push-pull and one symmetrical compound are reported. In addition, a blue-emitting LED was fabricated whose performances at 10 mA/cm 2 are a luminous efficiency of 3.9 cd/A, a power efficiency of 1.4 lmAV, and an external quantum efficiency of 2.9%. Thus, this versatile synthetic route is of particular interest due to the potential applications of the chromophores in several optoelectronic fields.
Keywords
Chromophores
Derivatives
Electronic structure
Esters
Light emitting diodes
Liquid crystals
Optical properties
Quantum efficiency
Electron acceptor
Electron-donor
Lasing properties
Suzuki reaction
Olefins
3 bromopyridine derivative
6' distyryl 3
3' bipyridine derivative
bipyridine derivative
unclassified drug
vinyl derivative
absorption spectroscopy
article
blue light
carbon nuclear magnetic resonance
chemical reaction
chromatophore
conjugation
cyclic potentiometry
differential scanning calorimetry
electrochemical analysis
electron
electronics
fluorescence spectroscopy
Knoevenagel condensation
light emitting diode
liquid crystal
nonlinear optical chromatophore
optics
photoluminescence
proton nuclear magnetic resonance
Siegrist reaction
synthesis
X ray diffraction