Synthesis of Luminescent Phosphine-Containing Rigid-Rod Dinuclear Alkynylgold(I) Complexes and Their X-Ray Structural, Photophysical, Self-Assembly and Electroluminescence Studies

Abstract

A series of rigid-rod dinuclear alkynylgold(I) complexes bearing triethylene glycol monomethyl ether or dibutoxy-substituted oligo(p-phenylene ethynylene)s moieties as the backbone, and phosphine ligands that are charge-neutral or bear a positive or negative charge, has been designed and synthesized. The alkynylgold(I) complexes with charge-neutral phosphines are found to show polymeric zig-zag chain structure with short gold‧‧‧gold distances in their X-ray crystal structures, while those with negatively charged phosphine ligands demonstrate spherical aggregates in dimethyl sulfoxide (DMSO)-water dispersions. The aggregation behaviour of the complex with positively charged phosphine ligand is found to follow an isodesmic mechanism upon increasing the water content in DMSO. Representative complexes have been applied as the emitting material in solution-processed organic light-emitting devices, exhibiting sky-blue emission with emission maxima at 432 nm. This work has provided further insights into the aggregation behaviour of this class of alkynylgold(I) complexes, as well as the understanding of their molecular packing and alignment for the future design of structurally-related rigid-rod organometallic materials.