Versatile Emissive Three‐Coordinated Gold(I) Systems‐Properties and Perspectives

Abstract

Trigonal planar coordination at gold allows phosphorescent 3 MC 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.

Enhanced circularly polarized luminescence of chiral Eu(iii) coordination polymers with structural strain

“…Transition metal complexes in their ligand-to-metal charge transfer (LMCT) or metal-to-ligand charge transfer (MLCT) states exhibit characteristic photofunctional properties such as photocatalytic activity, [1][2][3][4][5][6] solar cell efficiency, [7][8][9] and luminescence behavior. [10][11][12][13] Ritter provided the synthetic method of aryl fluoride from benzoic acids using LMCT excited states of a Cu(II) complex. 4 Moreover, Wenger recently reported characteristic MLCT luminescence from air-stable Mn(I) complexes with isocyanide chelate ligands.…”

Linkage of the Dinuclear Gold(I) Complex Luminescence and Origin of Endocyclic Amino Group of Cyclic P2N2-Bridging Ligands

“…Gold­(I) complexes have been intensely studied in the last two decades due to their rich photophysical properties and bioactivity allowing them to be considered as promising candidates in a broad field of applications, e.g., optoelectronics, chemosensors, sensors for mechanic stress, biosensors, anticancer agents, etc. − The presence of metal–metal interactions (aurophilicity) − is considered to be responsible for both the intense photoluminescence and for the stimuli responses of the luminescent characteristics.…”

“…In the dinuclear gold­(I) complexes, the ability to “switch on/off” the aurophilic interactions as usual depends on the conformational lability of the ligand backbone. ,− This switching of the aurophilicity is one of the important characteristics in the view of luminescent sensor design. Due to the wide variety of structural motifs, the luminescence of the gold­(I) complexes is possibly caused either by the metal-centered (MC) transitions for the polynuclear complexes with three-coordinated gold­(I) ions ,− or metal-to-ligand charge transfer (MLCT) and intraligand charge transfer (ILCT) transitions for the two-coordinated gold­(I) complexes. ,− …”