Recent Progress on the Exploration of the Biological Utility of Cyclometalated Iridium(III) Complexes

Abstract

Molecular imaging employing cyclometalated Ir(III) complexes is one of the fastest growing research areas. In this minireview, the key advances in phosphorescent bioimaging and photodynamic applications employing cyclometalated Ir(III) complexes are introduced. Focus is on understanding the structure−property relationships, with the aim to provide useful guidance to future development of molecular materials showing the intended photofunctions. The research covered in this minireview demonstrates that cyclometalated Ir(III) complexes can serve as versatile platforms for biological applications.

Ancillary Ligand Effects on Red‐Emitting Cyclometalated Iridium Complexes

“…Phosphorescent iridium(III) complexes have been extensively used in numerousa pplications,s uch as bioimaging, [1][2][3][4][5] photoredox catalysis, [6][7][8] and sensing. [9,10] The most prolifica nd commerciallyf ruitful application has been in optoelectronic technology,i ncludingorganic light-emitting diodes( OLEDs) [11][12][13][14] and light-emitting electrochemical cells.…”

3D vs. turbostratic: controlling metal–organic framework dimensionality via N-heterocyclic carbene chemistry

“…The final fit results thus indicate three types of atoms coordinated to iridium: C1 at 2.00(8) Å (Ir-benzene ring), C 2 at 2.06(8) Å (Ir-NHC) and O1 at 2.16(8) Å (Ir-THF), all with a coordination number of 2.6(3). It is expected that this complex has a +1 total charge, 45–50 and therefore, possesses a counterion, which is most likely BF 4 − originating from the NHC ligand precursor. The small quantity of Ir( i ) seen in the XPS data is explained by the fractional presence of Ir( i )-NHC complexes coordinated to the cod ligand; these complexes were not refined separately and thus, likely explain the small increase in the EXAFS coordination number when compared to the expected value of 2.…”

Unexpected reactivity of cyclometalated iridium(iii) dimers. Direct synthesis of a mononuclear luminescent complex

“…Phosphorescent cyclometalated iridium( iii ) complexes displaying strong and tunable emission have been the subject of intense research and many interesting applications. They have been extensively used in different fields, such as optoelectronic technology (OLED or LEC), 1,2 biocompatible probes for in vitro bioimaging, 3–8 photoredox catalysis, 9 and sensing 10,11 thanks to their peculiar features, such as chemical inertness, good thermal and photostability, and, most importantly, photophysical properties. The latter can be finely tuned with simple chemical modifications of the ligands coordinated with the metal center.…”