Platinum emitters with dye-based σ-aryl ligands

Phosphorescent Cyclometalated Platinum(II) Enantiomers with Circularly Polarized Luminescence Properties and Their Assembly Behaviors

“…Phosphorescent organoplatinum­(II) complexes have recently been extensively utilized to construct a wide variety of supramolecular materials because of their unique square-planar geometry and propensity to form noncovalent metal–metal interactions, which would render the molecules to aggregate, resulting in intriguing luminescence properties. − For example, drastic color and emission changes are found to occur during the assembly process, which can be attributed to the formation of noncovalent metal–metal and π–π stacking interactions. − In view of the fascinating spectroscopic properties, platinum­(II) complexes with functional ligands have also been exploited as sensors to afford color or phosphorescence changes in response to microenvironmental changes. − The rich and tunable emission colors and high photoluminescence quantum yields have also rendered them promising candidates for the fabrication of organic light-emitting diodes. − Recently, with the upsurge of research focusing on CPL materials, a few examples of platinum­(II) complexes with chiral groups modified on the bidentate or tridentate ligands have been reported with the amplification of CPL from the molecular level to assembled supramolecular architectures. ,− Apart from this, the decoration of ancillary ligands can also alter the solubility, photophysical, and self-assembly properties of platinum­(II) complexes. − Herein, we designed and synthesized a series of cyclometalated 1,3-di­(2-pyridyl)­benzene platinum­(II) complexes modified with different functional groups on the ancillary alkynyl ligands (Scheme ). They are capable of assembling into different aggregates through isodesmic self-assembly processes.…”

The iClick Reaction of a BODIPY Platinum(II) Azido Complex with Electron-Poor Alkynes Provides Triazolate Complexes with Good 1O2 Sensitization Efficiency

“…As these complexes also exhibit short excited-state lifetimes in the low- to mid-nanosecond range in air-equilibrated solution and their emission quantum yields are low, other emitters with better photophysical characteristics appear to be promising synthetic targets. In this context, the PtX­(PEt 3 ) 2 (Et = ethyl) moiety with a range of monoanionic ligands X = Cl, NO 2 , NCS, and CH 3 σ-bonded to a 4,4-difluoro-4-bora-3 a ,4 a -diaza- s -indacen-8-yl (BODIPY) group was recently identified to show efficient intersystem crossing (ISC) from an excited singlet to a BODIPY-centered triplet state, together with dual fluorescence and phosphorescence emission from the BODIPY ligand. − However, introduction of an iodo ligand led to significant quenching of the singlet emission, while the phosphorescence remained more or less unchanged compared to the other complexes . Therefore, we were curious to see whether the replacement of the halido by an azido group would shut down both emission channels and if formation of a triazolate ligand in the course of the iClick reaction might restore the photophysical properties of the parent compound.…”

Arylamidoethyl-Functionalized Imidazolium Salts: Precursors for Dianionic [C,N,C]2– Carbene Ligands at a Platinum Center

“…In combination with the results of quantum chemical calculations (see below), these observations suggest that the emission may be assigned to mixed 3 LL′/MLCT excited states. Due to the structured emission band, a considerable admixture of an IL excited state seems reasonable and is not unusual for emissive cyclometalated platinum complexes. − …”