Multi-functional bis(alkynyl)gold(iii) N⁁C complexes with distinct mechanochromic luminescence and electroluminescence properties.

A new class of donor-acceptor type luminescent bis(alkynyl)gold(iii) N⁁C complexes has been synthesized and characterized. These gold(iii) complexes not only exhibit high photoluminescence quantum yields of up to 0.81, but also interesting mechanochromic luminescence behaviors that are reversible. Upon grinding, a dramatic luminescence color change from green to red can be observed in solid samples of the gold(iii) complexes, and the mechanochromic luminescence can be readily tuned via a judicious selection of substituents on the pyridine ring. In addition, solution-processable OLEDs based on this class of complexes with EQE values of up to 4.0% have been realized, representing the first demonstration of bis(alkynyl)gold(iii) N⁁C complexes as emissive materials in solution-processable OLEDs.

Versatile Synthesis of Luminescent Tetradentate Cyclometalated Alkynylgold(III) Complexes and Their Application in Solution-Processable Organic Light-Emitting Devices.

A new class of cyclometalated tetradentate alkynylgold(III) complexes has been successfully synthesized by post-synthetic modification. Through the judicious design and choice of pincer ligands, post-synthetic cyclization could be achieved to produce the robust and structurally rigid class of tetradentate gold(III) C^N^C^C complexes with high photoluminescence quantum yields of up to 0.49 in solution and 0.78 in doped thin films at room temperature, at least an order of magnitude higher than those of the structurally related uncyclized tridentate alkynylgold(III) analogues. High-performance yellow to orange-red emitting solution-processable organic light-emitting devices have also been achieved with external quantum efficiency of 11.1 %. This work describes for the first time of the use of post-synthetic ligand modification approach to overcome the synthetic challenge for tetradentate alkynylgold(III) complexes.

Air-Stable Spirofluorene-Containing Ladder-Type Bis(alkynyl)borane Compounds with Readily Tunable Full Color Emission Properties.

A series of air-stable spiro-fused ladder-type boron(III) compounds has been designed, synthesized, and the electrochemistry and photophysical behavior have been characterized. By simply varying the substituents on the pyridine ring and extending the π-conjugation of the spiro framework, the emission color of these compounds can be easily fine-tuned spanning the visible spectrum from blue to red. All compounds exhibit a broad and structureless emission band across the entire visible region, assigned as an intramolecular charge-transfer transition originating from the thiophene of the spiro framework to the pyridine-borane moieties. In addition, these compounds demonstrate high photoluminescence quantum yields of up to 0.81 in dichloromethane solution and 0.86 in doped thin films. Some of the compounds have also been employed as emissive materials, in which solution-processed organic light-emitting devices (OLEDs) with tunable emission colors spanning the visible spectrum from blue, green to red have been realized, demonstrating the potential applications of these boron compounds in OLEDs.