Synthesis, Structures, and Unique Luminescent Properties of Tridentate C^∧C^∧N Cyclometalated Complexes of Iridium

Abstract

The first C ∧ C ∧ N cyclometalated complexes of iridium that bear tridentate pyridylbiphenylene ligands are reported herein. These complexes were synthesized in good yields by means of the directed C-C bond activation of biphenylene with the assistance of pyridyl group precoordination. Their

Formation of 5-membered metallacycles at iPrPCPIr by C–H, O–H, and C–CO bond cleavage

“…These results indicate that the reaction of the iPr PCPIr fragment with biphenyl involves a double C-H activation with concomitant release of hydrogen (Scheme 3). While metallofluorene complexes of iridium are known, they have all been synthesized/ observed by reaction of 2,2 0 -dilithiobiphenyl with an iridium halide [35], by C-C activation of biphenylenes [30,36,37], or net C-CO and C-H activation of 2-arylbenzoyl chlorides [38]. To the best of our knowledge, the PCPIr system is the first example of iridium 2,2 0 -biphenyl complexes formed by double C-H activation, although double C-H activation of biphenyl with (dtbpm)Pt 0 is known [39].…”

Ring‐Shaped Silafluorene Derivatives as Efficient Solid‐State UV‐Fluorophores: Synthesis, Characterization, and Photoluminescent Properties

“…Intermolecular interactions in bulk solid can not only significantly alter the positions of the peaks in the emission spectra, but also can result in large changes in the luminescent intensity. [17] Many pathways, such as vibration (e.g., angle bending), [19] energy transfer between orbitals of similar levels, [20] short stacking distance, [21] and so forth, can contribute to possible fluorescence quenching or decay because of relaxation processes. Among these paths, short distance (5)(6) intermolecular interactions between fluorophores stacking on top of each other can lead to fluorescence decay in solid state because of enhanced exciton-phonon coupling.…”

Luminescent (N^C^C) Gold(III) Complexes: Stabilized Gold(III) Fluorides

“…Their solution emission quantum yields are in most cases over 0.16 and up to 0.28, aremarkable value in the arena of gold(III) emissive compounds.B esides the commonly encountered acetylides or NHC sigma donor ligands, also chloride and even af luoride ligand are able to activate the intraligand state ( 3 IL) emission of the corresponding cyclometalated Au III complexes,w ith 0.17 and 0.27 quantum yields,r espectively.A ss uch, the remarkable luminescent behavior of these compounds needs to stem from the special arrangement of the N^C^C scaffold. [16] Unlike most Au III compounds,w hich exhibit luminescence only at low temperature or are non-emissive,c omplexes 2-7a display luminescence in solution at ambient temperature and are comparable or even improve the performance of emissive classical (C^N^C)-pincer and (N^C)-phenylpyridine Au III complexes. [2,3,4a, 5b,17] In summary,anovel N^C^C pincer framework, able to stabilize gold in high oxidation state,i sr eported here.T he first examples of C(sp 2 )-gold(III) fluorides obtained through am ild Cl/F ligand exchange reaction have been described.…”