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Ag(Ⅰ) complexes based on benzothiazole-phosphine ligands exhibit bright long-lived phosphorescence at 298 K. [Display omitted] • Two ionic silver(I) complexes based on benzothiazole-phosphine N^P ligands have been synthesized. • Two complexes in powder exhibit bright long-lived phosphorescent emissions at 298 K. • The coordination geometries around Ag(I) centers adopt distorted tetrahedron (1) and trigonal planar (2), respectively. Two ionic mononuclear silver(I) complexes (1 and 2) with formula of [Ag(N^P)(Xantphos)]SbF 6 , where N^P = 2–(benzo[ d ]thiazol)–2–yl) diphenylphosphine derivatives, Xantphos = 4,5-Bis(diphenylphosphino)-9,9-dimethylxanthene, have been synthesized and characterized. Single crystal analysis reveals that the geometries around Ag(I) centers adopt distorted tetrahedron (1) and trigonal planar (2). In powder at 298 K, these complexes exhibit bright emissions with high photo-luminescent quantum yields of 55.2 % (1) and 46.7 % (2) and lifetimes of 0.426 ms (1) and 1.87 ms (2), respectively. The results suggested that these complexes containing bulky benzothiazole phosphine can realize efficient long-lived phosphorescence. [ABSTRACT FROM AUTHOR]

Three-coordinate mononuclear copper(I) halide complexes (1 (I) and 2 (Br)) that bear a novel rigid diphosphine ligand derived from a benzimidazole skeleton were prepared and characterized. Structural analyses of 1 and 2 reveal that the rigidity of the functionalized diphosphine ligand leads to weak Cu⋯πimidazole interactions. Solid state luminescence studies show that the existence of cation–π interactions and the heavy atom effect facilitate orange-red emission (630 nm for 1 and 615 nm for 2) with high photoluminescence quantum yields (65% and 72% for 1 and 2, respectively) and decay times of a few tenths of microseconds. The combination of experimental results and quantum-chemical calculations reasonably reveals that the emission origin is assigned to TADF-assisted phosphorescence based on (metal + halide) to ligand transitions. This systematic study demonstrates that the introduction of a functional π-conjugated bridging moiety between the two P atoms in the diphosphine ligands is a promising strategy for developing new structures with high luminescence performance. [ABSTRACT FROM AUTHOR]

A series of new luminescent cycloplatinated(II) complexes (5a–8a and 5b–8b) with formulas Pt(bt)(N^O) and Pt(bt)(N^P) have been synthesized [bt = phenylbenzothiazole, N^O = (2-(1H-benzimidazole)-phenyl)diphenylphosphine oxide derivatives for 1a–4a and N^P = (2-(1H-benzimidazole)-phenyl)diphenylphosphine derivatives for 1b–4b]. The crystal structures of the complexes show distorted square planar geometries around the platinum centers. There are no obvious π–π and Pt–Pt intermolecular interactions in the crystal lattice due to the presence of sterically bulky ancillary ligands. Consequently, these complexes exhibit structured monomeric emissions in the range of 527–540 nm in CH2Cl2 solution. The photoluminescent quantum yields of Pt(bt)(N^O) (5a–8a) in CH2Cl2 solution at room temperature are higher than those of Pt(bt)(N^P) (5b–8b). The above result is well consistent with the crystal structural characteristics of the complexes. The structured emission with microsecond radiative lifetimes and the result of TD-DFT calculations indicate that the emissions of these complexes are mainly attributed to a mixed 3LC-MLCT state. [ABSTRACT FROM AUTHOR]

Four mono‐ and two dinuclear Cu(I) complexes were synthesized based on novel 4‐diphenylphosphino‐benzimidazole (P^N) derivatives, and their structures as well as photophysical properties were systematically investigated. X‐ray crystallographic analysis reveals that the Cu(I) centers adopt pseudo‐tetrahedral geometries. All the complexes in powder at 293 K display bright phosphorescence with the highest photoluminescent quantum yield of 37.6 %. The emission maxima could be finely tuned from 514 to 592 nm by the methoxy substituent on the N^P ligands. The combined experimental results at different temperature (293 K and 77 K) and theoretical studies suggest that the nature of the emissive states can be mainly assigned as a dominant charge‐transfer character involving major components of 3(M+X) LCT transitions. [ABSTRACT FROM AUTHOR]

Phosphorescent four-coordinate Cu(I) complexes (1–3) of the type [CuI(PPh3)(N^P)], N^P = 4-(diphenylphosphanyl)-1,2-diphenylbenzimidazole derivatives, have been synthesized and characterized. Under UV excitation, the title complexes in the solid-state exhibit intense emission with a photoluminescence quantum yield of 35% and a short decay time (τ < 11 μs) at 290 K. The involvement of the methoxy group allows the tuning of the photoluminescent maxima from 568 to 589 nm. The combined experimental and density functional theory results suggest that the luminescence of the complexes represents phosphorescence attributed to the 3(M + X)LCT transitions. The prototype solution-processed devices with the complexes as an emitting dopant realize high electroluminescent performance. In particular, the OLED based on 3 achieves a maximum EQE value of 3.08%, which is equivalent to 52% of the respective theoretical maximum, suggesting that the cheap and environmental cuprous complexes are potential alternatives to the luminescent noble metal complexes. [ABSTRACT FROM AUTHOR]

Three dinuclear copper(I) complexes (1, 2 and 3) of the form [(P N)Cu]2(μ2‐I)2 have been designed and synthesized with 4‐diphenylphosphino‐benzimidazole (P N) derivatives. X‐ray structural analysis shows that the complexes possess one rhombohedral Cu2I2 dimer that is coordinated with two P N ligands and exhibits a trans‐configuration. At 290 K, the copper complexes exhibit similar broad and featureless emission bands with peak maxima (λmax) at 585 nm, 565 nm and 586 nm, respectively. The temperature‐dependent photophysical behaviors accompanied with the theory calculations demonstrate that 1 represents a thermally activated delayed fluorescence behavior at ambient temperature, whereas luminescence of 2 and 3 is phosphorescence. Moreover, the complexes (1–3) achieve high photoluminescence quantum yields of 36.9 %, 43.0 % and 34.0 % with relatively short emission decay times of 5.85 μs, 7.99 μs and 5.99 μs, respectively. The solution‐processed organic light‐emitting diode based on 1 achieves a peak brightness of 3325 cd m−2 and an EQE of 2.99 %. [ABSTRACT FROM AUTHOR]

The zinc complex ZnE containing two 2-(2'-hydroxyphenyl)-1-ethyl-4-hydroxybenzimidazole (EtL) ligands has been designed and synthesized. The zinc ion acts as a spacer linking the two coordinated EtL, between which intramolecular hydrogen bonds form. Upon excitation, in addition to a weak emission at 399 nm, ZnE exhibits strong excited-state intramolecular proton-transfer (ESIPT) emission with a maximum at 479 nm with a large Stokes shift (8449 cm-1) in tetrahydrofuran solution. Importantly, the ESIPT in ZnE also takes place in the powder form, resulting in dual emission (407 and 490 nm) with total photoluminescence quantum yields (Φ) of 0.16. The results of quantum calculations suggest that the ESIPT fluorescence is based on a zwitterionic excited-state species resulting from a single proton transfer between the ligands. [ABSTRACT FROM AUTHOR]

• Pt(II) complexes (piq)Pt(N^O) (1–4) and (piq)Pt(N^P) (5–8) have been synthesized. • All complexes display distorted square-planar geometries around pt(II) center. • The complexes show good monomeric emissions with the PLQYs up to 23% in DCM at 298 K. • he complexes exhibit different emission colors by changing the ancillary ligands. Eight neutral luminescent cyclometalated platinum(II) complexes with general formula (piq)Pt(N^O) and (piq)Pt(N^P), where piq = 1-phenylisoquinoline, N^ O = deprotonated (2-(1H-benzimidazole)-phenyl)diphenylphosphine oxide derivatives and N^ P = deprotonated (2-(1H-benzimidazole)-phenyl)diphenylphosphine derivatives, have been synthesized and characterized. These complexes display distorted square-planar molecular geometries around platinum(II) centers without obvious π-π interactions and Pt-Pt metallophilic interactions in the crystal lattice, due to the presence of sterically bulky N^O and N^P benzimidazole ancillary ligands. Hence, these complexes exhibit good monomeric emissions with the luminescent quantum yields of 15%-23%, which are far more than that of (piq)Pt(acac) (0.9%) in dichloromethane (DCM) at 298 K. The emission colors of platinum(II) complexes can be finely tuned in the range 600–645 nm by changing the chelating types of ancillary ligands. The structured emission combined with microsecond emission lifetimes and the support of TD-DFT calculations for these complexes indicate that their emissions mainly come from an admixture of intraligand (3ILCT) and metal-to-ligand charge transfer (3MLCT). [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Three neutral Cu(I) complexes (Cu01, Cu02 and Cu03) with general formula NˆPCuI(PPh 3), where NˆP = 2-(2′-diphenylphosphinophenyl)-1-phenylbenzimidazole derivatives, are synthesized and characterized. The crystal structures of the complexes suggest that the central Cu(I) ion is tetra-coordinated by bidentate PˆN ligand, iodide and ancillary triphenylphosphine ligand, forming a distorted tetrahedron configuration. At 293 K, all complexes in powder exhibit intense emissions (Cu01 581 nm, Cu02 557 nm, Cu03 575 nm) with quantum yield up to 38% (Cu01), implying their potential application as emitters in organic light-emitting diode (OLED). In addition, the thermal stability of Cu01 is confirmed by the luminescence spectrum from evaporated amorphous films. Vapor-deposited OLED based on Cu01 is fabricated, showing a peak external quantum efficiency of 3.4%, a peak current efficiency of 10.0 cd/A, and a maximum brightness of 1806 cd m−2. Graphical abstract Novel thermally stable cuprous complexes (Cu01, Cu02, Cu03) are designed and synthesized based on the asymmetrical iminephosphine (PˆN) ligands. Vapor-deposited OLED based on Cu01 is fabricated, showing a stable emission (613 nm) with a peak external quantum efficiency of 3.4%, a peak current efficiency of 10.0 cd/A, and a maximum brightness of 1806 cd m−2. Image 1 Highlights • Novel thermally stable cuprous complexes are obtained based on the asymmetrical iminephosphine (PˆN) ligands. • At 293 K, the cuprous complexes in powder exhibit intense emission with quantum yield up to 38% (Cu01). • Vapor-deposited OLED based on Cu01 shows a stable emission (613 nm) with a peak external quantum efficiency of 3.4%. [ABSTRACT FROM AUTHOR]

Phosphorescent cuprous complexes (1 – 6) with general formula CuI(N^P) (PPh 3), where N^P = 2-(2′-diphenylphosphinophenyl)-1-phenyl-5-methoxybenzimidazole derivatives, have been designed and synthesized. The crystal structures of the neutral four-coordinated Cu(I) complexes are determined by single crystal X-ray diffraction. At 293 K, these complexes exhibit intense phosphorescence with exceptionally high photoluminescence quantum yields (up to 88.3%) and short decay times (4.8–55.2 μs). The emission maxima can be fine-tuned from 529 nm to 577 nm, depending upon the number and position of methoxy substituent on the N^P ligand. Especially, complex 5 exhibits phosphorescence (533 nm) with photoluminescence quantum yield of 70.5% and decay time of 19.5 μs, implying its potential to serve as a phosphor for organic light emitting diode (OLED). Solution-processed OLED incorporating complex 5 as dopant emitter achieves a maximum brightness of 7729 cd with CIE coordinates (0.4351, 0.5398), constituting a step further toward the design of cuprous complexes as cheap and environmental alternatives to the luminescent noble metal complex. A series of luminescent cuprous complexes (1 – 6) with general formula CuI(N^P) (PPh 3) have been designed and synthesized. Especially, complex 5 shows phosphorescence (533 nm) with high PLQY of 70.5% at short decay time (19.5 μs). Bright electroluminescence (558 nm) of up to 7729 cd m−2 has been observed based on phosphor 5 as dopant in a simple solution-processed OLED, which manifests its great potential in the fabrication of bright OLEDs. Image 1 • Cuprous complexes (1-6) with general formula CuI(N^P)(PPh 3) have been synthesized. • The complexes realize bright phosphorescence with Φ of up to 88.3% and lifetime shorter than 55.2 µs at 293 K. • Complex 5 shows phosphorescence with Φ of 70.5% and decay time of 19.5 μs at 293 K. • Solution-processed OLED based on phosphor 5 achieves a maximum brightness of 7729 cd m-2. [ABSTRACT FROM AUTHOR]