Pyridyl Azolate Based Luminescent Complexes: Strategic Design, Photophysics, and Applications

Abstract

This chapter summarizes the deliberate design of the chelating C -linked 2 -pyridyl azolate ligands. Attempts have been made in ligand functionalization and modification to fi ne -tune the photophysical properties of the associated metal complexes. Moreover, this chapter also reports the synthetic strategies, leading to a series of high emissive, boron as well as osmium, ruthenium, iridium, and platinum metal complexes, which all possess at least one 2 -pyridyl azolate chromophore. Spectroscopic and dynamic measurements, in combination with theoretical analyses, have thus gain much insight into their electronically excited state properties such as the energy gap and nature of the lowest lying excited states, mechanism of intersystem crossing, and the effi ciency of corresponding radiative decay and nonradiative deactivation processes. From the application point of view, efforts have been made to the exploitation of these emitting materials as dopants for preparation of high effi ciency, true -blue and saturated -red polymer light -emitting diodes (PLEDs), and organic light -emitting diodes (OLEDs). IntroductionThe transition -metal complexes incorporating simple diimine ligands [1] such as 2,2 ′ -bipyridine (bpy) and/or cyclometalated ligands [2] such as 2 -phenyl pyridine (ppy) have attracted a great interest in recent years. Research work in this area was principally motivated by the use of these complexes in the study of excitedstate electron and energy transfer [3] as well as the potential applications in the fabrication of chemical sensors, photovoltaics and organic light -emitting diodes (OLEDs) [4] .

Difluoroboron Complexes Based on Benzimidazole–Phenolates as Blue Emitters

“…In the tetracoordinated boron compounds, boron bonded to a π-conjugated chelate with different architectures, producing luminescent materials with high carrier mobility. These compounds find applications in organic light-emitting diodes (OLEDs) − and organic field effect transistors, , functioning as emitting and electron-transport materials. Additionally, they are used in photosensitive, sensory, − and bioimaging applications, showcasing their versatility across various technological domains. , …”