Luminescent Organogold(III) Complexes with Long‐Lived Triplet Excited States for Light‐Induced Oxidative CH Bond Functionalization and Hydrogen Production

Abstract

All that glitters is gold: highly phosphorescent gold(III) complexes with extended π-conjugated cyclometalating ligands exhibit rich photophysical and photochemical properties. They act as efficient photocatalysts/photosensitizers for oxidative functionalizations of secondary and tertiary benzylic amines and homogeneous hydrogen production from a water/acetonitrile mixture.

The chemistry of amine radical cations produced by visible light photoredox catalysis

“…The Che group synthesized a photoactive gold(III) complex that was shown to catalyze α-cyanation of N -aryltetrahydroisoquinolines [75]. Very recently, Zhu and coworkers used an analogous gold(III) complex to catalyze the reactions similar to those reported by the Rueping group (Scheme 9) [76].…”

Thermally Stable Donor–Acceptor Type (Alkynyl)Gold(III) TADF Emitters Achieved EQEs and Luminance of up to 23.4% and 70 300 cd m−2 in Vacuum‐Deposited OLEDs

“…[3][4][5][6][7] Due to the electrophilic nature/relatively high reduction potential of Au(III) ion, the luminescent excited states of Au(III) complexes are usually ligand centered with little metal character, resulting in long triplet emission lifetimes, [8][9][10][11][12][13][14][15] thereby posing significant challenges to achieve high performance OLEDs with low efficiency roll-off at high luminance and driving voltage. The first example of gold OLED was reported by Ma and Che in 1999 [1,2] with inferior performance, and device performance has been improved in recent years exploiting luminescent cyclometalated Au(III) complexes.…”

Light-induced catalytic and cytotoxic properties of phosphorescent transition metal compounds with a d 8 electronic configuration

“…In the presence of light irradiation, Au2 could effectively catalyse the aerobic oxidation of secondary amines to imines and C−H bond functionalization of tertiary amines with nucleophiles such as cyanide and nitromethane (figure 15). The results described in To et al [34] could be favourably compared with the related literature findings when considering the low catalyst loading used (0.15 mol%). While luminescent platinum(II) compounds are well documented to sensitize light-induced hydrogen production from aqueous medium, there has been no report on using gold(III) compounds for light-induced hydrogen production prior to the report of To et al [34].…”

“…The results described in To et al [34] could be favourably compared with the related literature findings when considering the low catalyst loading used (0.15 mol%). While luminescent platinum(II) compounds are well documented to sensitize light-induced hydrogen production from aqueous medium, there has been no report on using gold(III) compounds for light-induced hydrogen production prior to the report of To et al [34]. Recently, Au2 was found to sensitize photoinduced hydrogen production by irradiating a degassed acetonitrile/water mixture of Au2 been used as phosphorescent dopants in organic light-emitting diodes [5,6].…”

“…As discussed in §3, the [Au(C ∧ N ∧ C)(NHC)] + compounds containing extended π-conjugated C ∧ N ∧ C ligands (Au2 and Au3) have long phosphorescence lifetimes (506 μs for Au2; 282 μs for Au3) and high emission quantum yields (11.4% for Au2; 5.5% for Au3) [34], making them good candidates as effective photooxidative catalysts and photosensitizers for PDT. Although these compounds are non-emissive at room temperature due to efficient quenching of their phosphorescence by oxygen, they could be used as luminescent probes for cell imaging under hypoxia conditions.…”