Colour-tunable asymmetric cyclometalated Pt(ii) complexes and STM-assisted stability assessment of ancillary ligands for OLEDs

Abstract

The DFT-guided and STM-assisted realization of tunable triplet emitters is reported.

Metal Complexes with Azolate‐Functionalized Multidentate Ligands: Tactical Designs and Optoelectronic Applications

“…The last example of Pt II complexes bearingt he dianionic tridentate chelate were assembled using the class of 2-phenyl-6-(1,2,4-triazol-5-yl) pyridine, that is, tz Bu pyPh 2F H 2 ,t ogether with four distinctive ancillaries, namely:P Ph 3 (60), 4-amylpyridine (61), 2,6-dimethylphenylisocyanide (62), and tert-butylisocyanide (63). [61] It revealed that the steric interference between the cyclometalated phenylg roup adjacent to the ancillary (L) has forced the out-of-plane tilting and twisting of this monodentate ligand.D epending on their bulkiness, variable tilt anglesa re obtained that also block the intermolecular interactions to differente xtents, affordingv ariable emission color in the regime from green, orange to red in the solid state. STM analysisa lso revealed the formation of stable self-assembled monolayers for 60 and 62,b ut yieldedd ecomposition of 61 and 63 under ultrahigh vacuum conditions, showingt he crucial role played by the propers election of the ancillary ligand.…”

“…The last example of Pt II complexes bearing the dianionic tridentate chelate were assembled using the class of 2‐phenyl‐6‐(1,2,4‐triazol‐5‐yl) pyridine, that is, tz Bu pyPh 2F H 2 , together with four distinctive ancillaries, namely: PPh 3 ( 60 ), 4‐amylpyridine ( 61 ), 2,6‐dimethylphenylisocyanide ( 62 ), and tert ‐butylisocyanide ( 63 ) . It revealed that the steric interference between the cyclometalated phenyl group adjacent to the ancillary (L) has forced the out‐of‐plane tilting and twisting of this monodentate ligand.…”

Fluorination‐controlled Aggregation and Intermolecular Interactions in Pt(II) Complexes with Tetradentate Luminophores

“…Such interactions are favored by the square‐planar geometry of the d 8 ‐configured metal center and driven by the occurrence of π⋅⋅⋅π interactions favoring intermolecular d z 2 ⋅⋅⋅d z 2 coupling. For monomeric Pt(II) species, the emission is known to occur from metal‐perturbed ligand‐centered triplet states ( 3 MP‐LC), whereas the aggregates emit from excimeric or metal−metal‐to‐ligand charge‐transfer states ( 3 MMLCT) possessing a red‐shifted luminescence and shortened excited state lifetimes . In any case, the involvement of the Pt(II) center in the electronic transitions is essential for the otherwise spin‐forbidden phosphorescence, as it significantly enhances spin‐orbit coupling and mixing of states with different multiplicities.…”

Synthesis, crystal structure, photophysical property and metal ion-binding behavior of a cyclometalated platinum(ii) terpyridylacetylide with efficient π-conjugation degree

“…3 Owing to their intriguing spectroscopic and luminescence properties, square-planar platinum(II) polypyridyl complexes imparted with metal-binding units, such as P-and N-donor crown ether pendants, 4 S-benzo-15-crown-5, 5 4-ethynylbenzo-15-crown-5, 6 5,17-diethynyl-25,27-dimethoxycalix [4]crown-5, 7 bipyridylacetylides, 8 and terpyridylacetylides, 9 have been reported in such investigations. Since the strong ligand eld effect of the cyclometalated carbon raises the energy of the d-d states to reduce the non-radiation decay probability, cyclometalated platinum(II) complexes with tridentate phenylsubstituted pyridine [(N^C^N) motif] [10][11][12][13][14][15][16] and bipyridine [(C^N^N) motif] [17][18][19][20][21][22] as well as the related diphenyl-substituted pyridine [(C^N^C) motif] 23,24 ligands are good emitters with high quantum yields at room temperature, which are expected to be used as better candidates in chemosensors. 25,26 Cyclometalated [(C^N^N)Pt(II)] s-alkynyl complex with a benzo-15azacrown-5 receptor 27 and a bis(2-picolyl)aniline (DPA) receptor 28 have been applied in ion-binding studies.…”