Synthesis, mesomorphism, photophysics and device performance of liquid-crystalline pincer complexes of gold(iii)

Abstract

Emissive gold(iii) complexes with liquid-crystalline properties have been prepared, with most complexes showing a columnar hexagonal phase. The emissive response has been characterised in solution and in OLED devices.

Synthesis, Mesomorphism, Photophysics, and Device Properties of Liquid-Crystalline Pincer Complexes of Gold(III) Containing Semiperfluorinated Chains

“…It is instructive to consider the data in the light of both the other complexes described in this work and the all-hydrocarbon analogues published previously. 35 …”

“…Thus, while 16a–c all form Col h phases, the phase ranges are narrow once melted from the solid, and in one sense, it is perhaps remarkable that they are liquid crystals at all given that they possess three terminal chains. Indeed, of the all-hydrocarbon equivalents, 35 only one shows a mesophase and that is monotropic. Considering the data obtained from SAXS, the columnar lattice parameters for 16a and 16c are a = 33.1 and 35.9 Å, respectively, which are greater than the longest possible dimension of a complex ( ca 28 Å from the 4-hydrogen on the pyridyl ring to the terminal methyl group of the dodecyl chain on the pincer).…”

“…The UV–visible absorption spectra of complexes 16 – 21 , recorded in dichloromethane solution at room temperature, are essentially identical to the spectra of the corresponding complexes featuring hydrocarbon chains. 35 Since the fluorinated regions of the chains are electronically isolated from the core of the molecules through the −(CH 2 ) 2 – linkage, their inclusion would not be expected to alter the electronic energies of any of the orbitals involved in absorption transitions in this region of the spectrum, nor the oscillator strengths of the transitions.…”

“…The thermal behavior is summarized in Table and is represented graphically in Figure , while the X-ray data are collected in Table S1. It is instructive to consider the data in the light of both the other complexes described in this work and the all-hydrocarbon analogues published previously …”

Organic Light-Emitting Diodes Based on Luminescent Self-Assembled Materials of Copper(I)

“…Since then, extensive research interest has been directed toward the design and synthesis of phosphorescent metal-based emitters for OLED applications. While precious metal complexes, such as those of iridium − and platinum, − are extensively used as the triplet emitters in phosphorescent OLEDs, advances in the field have led to the successful fabrication of efficient OLEDs based on complexes of osmium, − ruthenium, ,, gold, ,− and those based on earth-abundant elements, such as copper, , zinc, − tungsten, , and nickel . Apart from small molecules, the self-assembly of multiple metal centers into metal clusters and coordination polymers , has given rise to intriguing luminescence properties of metal-based materials.…”