Molecular design and application of luminescent materials composed of group 13 elements with an aggregation-induced emission property

Complexation of p-conjugated ligands by metal or semimetal ions leads to the enhancement of the planarity and rigidity of pi-conjugated systems. Boron, especially, has played a central role in the design of luminescent main-group complexes. However, these complexes still suffer the disadvantage of aggregation-caused quenching as well as typical organic fluorophores. It has recently been reported that some types of boron complexes exhibit the aggregation-induced emission (AIE) property. Moreover, AIE behavior from complexes and organometallic compounds composed of the other group 13 elements, such as aluminum and gallium, has emerged in this decade. These observations greatly encourage us to develop advanced functional materials based on the group 13 elements. Indeed, recent research has demonstrated that these classes of materials are potentially versatile scaffolds for constructing chromic luminophores, efficiently emissive pi-conjugated polymers and so on. This review mainly describes AIE-active group 13 complexes with four-coordinate structures and their application as photo-functional materials. Proposed mechanisms of the origins of AIE behavior are briefly discussed.

Automated summary

The complexation of p-conjugated ligands by metal or semimetal ions enhances the planarity and rigidity of pi-conjugated systems. Boron has a key role in the design of luminescent main-group complexes, but suffers from aggregation-caused quenching like typical organic fluorophores. Recent studies have shown that some boron complexes exhibit aggregation-induced emission (AIE) properties and AIE behavior has also been observed in complexes and organometallic compounds of other group 13 elements. These findings encourage the development of advanced functional materials based on group 13 elements, which are versatile scaffolds for constructing chromic luminophores and efficiently emissive pi-conjugated polymers.