Geometric isomers of asymmetric rigid four-membered chelating ring based deep-red-emitting iridium complexes featuring three charged (0, −1, −2) ligands

Abstract

Geometric isomers are very important and interesting in the field of optical materials. In this work, we have designed and synthesized a new series of geometric isomers of iridium complexes...

Three-Charge (0, −1, −2) Ligand-Based Binuclear and Mononuclear Deep-Red Phosphorescent Iridium Complexes Bearing Benzo[d]oxazole-2-Thiol Ligand

“…The fabricated devices with two mononuclear iridium complexes both show efficient deep red emission (629 nm for Ir1 , 632 nm for Ir2 ) with CIE x,y coordinates [(0.61, 0.33) for Ir1 , (0.62, 0.34) for Ir2 ] originating only from themselves (Figure b,c and Table S5), indicating an effective energy transfer from the host material to the guest material. In addition, the devices exhibit EQEs comparable to previously reported iridium complexes with similar CIE coordinates . Notably, the device EQE of complex Ir2 (5.5%) is significantly higher than that of Ir1 (3.5%) (Figure e and Table S5), which is attributed to the fact that the ligand 1,10-phenanthroline is more rigid than the ligand 2,2′-bipyridyl.…”

“…In addition, the devices exhibit EQEs comparable to previously reported iridium complexes with similar CIE coordinates. 21 Notably, the device EQE of complex Ir2 (5.5%) is significantly higher than that of Ir1 (3.5%) (Figure 4e and Table S5), which is attributed to the fact that the ligand 1,10-phenanthroline is more rigid than the ligand 2,2′-bipyridyl. In addition, both devices exhibit a low turn-on voltage (2.8 V; Figure 4d and Table S5), resulting from the good level matching of all materials, which facilitates carrier transport.…”

“…In addition, our group has recently reported a rigid asymmetric ligand benzo[d]thiazole-2-thiol, which can produce fourmembered chelate ring and realize a series of red-emitting iridium complexes with good properties. 21 Therefore, in this work, we selected a similar cheap rigid ligand benzo[d]oxazole-2-thiol and introduced it into the new system of iridium complexes with three-charge (0, −1, −2) ligands, hoping to obtain some interesting intermediates of binuclear iridium complexes and investigate the reaction mechanism.…”

“…For classical phosphorescent iridium complexes with three monoanionic (−1, −1, −1) ligands, such as typical green-emitting materials fac -Ir­(ppy) 3 and Ir­(ppy) 2 acac (Scheme a), a nonluminescent chloro-bridged binuclear complex intermediate is usually formed during their synthetic reaction, and then a luminescent mononuclear complex is further formed (Scheme a). Notably, as a new kind of phosphorescent materials, iridium complexes with three-charge (0, −1, −2) ligands − are easier to emit red light or even near-infrared light by using simple ligands than the traditional iridium complexes with three monoanionic (−1, −1, −1) ligands, so their development is very important. However, the structure and reaction mechanism of these complexes need to be further studied; especially, the reaction intermediates are not clear, and the binuclear luminescent complexes under this new structural framework have not been reported.…”

Magnetic and Porous Regulation in Cobalt(II) Hydrogen-Bonded Organic Framework via Supramolecular Isomerism

“…Isomerism is a typical and significant phenomenon in organic chemistry, which occurs when molecules have the same chemical composition and molecular formula but different spatial arrangements of atoms. These isomers, which can be small molecules or polymers, exhibit unique physical and chemical properties, including variations in thermal properties, boiling points, and crystallinity. − In recent studies, Zhou et al introduced the concept of “framework isomers” to describe isomerism in metal–organic frameworks (MOFs) . Supramolecular isomers usually refer to MOFs that contain the same nodes and linkers in the same ratio but differ in the nature or number of solvent molecules incorporated into the framework, resulting in distinct crystal structures .…”