Versatile emissive three-coordinated gold(I) systems-properties and perspectives

This article also appears in: Board Members RSEQ-GEQO Prize Winners.Trigonal planar coordination at gold allows phosphorescent 3MC transitions, not expected for luminescent mononuclear linear gold complexes. The careful selection and nature of the ancillary ligands bonded to gold, being fluorophore groups or not emissive ligands may cause a distortion of ideal trigonal planar coordination favoring different origins for the emissions. Consequently, intraligand (IL) or charge transfer (CT) transitions may be present and besides the expected phosphorescent MC transitions, fluorescence or thermally activated delayed fluorescence (TADF) may be the origin of the luminescence. In addition of the advantages of triplet population and deactivation via phosphorescent or delayed fluorescence processes, these systems are very versatile and may show interesting properties such as mechanochromism and vapochromism and, consequently, have revealed as promising candidates for optical applications. The objective of this review is to provide an overview of the reported luminescent three-coordinated gold systems and to get insight into their emissive properties.We thank the Agencia Estatal de Investigación PID2019-104379RB-C21 and DGA-FSE (E07_20R) for financial support. A. Alconchel appreciates the predoctoral contract award BES-2017-082997.Peer reviewe