Double decker NHC-cyclometallated Pt complexes for highly-efficient vacuum-deposited green OLEDs and NIR emission
Melendo, Irene ; Weatherill, Lucy A. ; Martín, Antonio ; Pander, Piotr ; Dias, Fernando B. ; Fuertes, Sara ; Sicilia, Violeta (Universidad de Zaragoza)
Resumen: The dinuclear compound [{PtII(C^C*)(µ-N^N)}2] (HN^N: diphenylformamidine; HC^C* = 3-methyl-1-(naphthalen-2-yl)-1H-imidazol-2-ylidene, 3) was obtained as a pure single anti-isomer, with a Pt–Pt distance of 2.8645 Å. Under UV light, 3 reacted with haloforms to obtain the corresponding oxidized species [{PtIII(C^C*)(µ-N^N)X}2] (4-X). X-ray analysis of 4-Cl confirmed the retention of the anti-conformation and revealed a shortened Pt–Pt distance (2.6070 Å) consistent with metal–metal bonding in the Pt2(III,III) system. In addition, methylation of the electron-rich complex 3 with [Me3O]BF4 provided the mixed-valence dinuclear species [(C^C*)PtII(µ-N^N)2PtIV(C^C*)(CH3)]BF4 (5), which exhibits two distinct 195Pt NMR resonances (δ: −2373 and −3264 ppm) and a large Pt–Pt coupling constant (2155 Hz). Compound 3 shows a structureless emission band at 520 nm in 2 wt% PMMA (poly(methyl methacrylate)) film, with a photoluminescence decay of 1.80 µs and quantum yield of 0.90, typical of triplet metal–metal–to-ligand charge transfer (3MMLCT) [dσ*(Pt–Pt) → π*(C^C*)] excited states. The oxidized counterparts, 4-X, display phosphorescent emissions with maxima at 960, 970 and 1055 nm in solid state at 77 K. These are tentatively assigned to triplet axial ligand-to-metal–metal charge transfer (3XMMCT) [σ(X) → dσ*(Pt–Pt)]. Whilst complex 5 shows no emission in either the visible or near-infrared regions at 298 or 77 K. Organic light-emitting diodes (OLEDs) incorporating 3 as a green emitter demonstrate excellent device performance, achieving a turn-on voltage of 3 V, an external quantum efficiency (EQE) reaching 22% and a maximum luminance exceeding 22 000 cd m−2.
Idioma: Inglés
DOI: 10.1039/d6qm00041j
Año: 2026
Publicado en: Materials Chemistry Frontiers (2026), [11 pp.]
ISSN: 2052-1537
Financiación: info:eu-repo/grantAgreement/ES/DGA/E17-23R
Financiación: info:eu-repo/grantAgreement/ES/MICIU/PID2024-155563NB-I00
Tipo y forma: Article (Published version)
Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)
You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. You may not use the material for commercial purposes.
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Idioma: Inglés
DOI: 10.1039/d6qm00041j
Año: 2026
Publicado en: Materials Chemistry Frontiers (2026), [11 pp.]
ISSN: 2052-1537
Financiación: info:eu-repo/grantAgreement/ES/DGA/E17-23R
Financiación: info:eu-repo/grantAgreement/ES/MICIU/PID2024-155563NB-I00
Tipo y forma: Article (Published version)
Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)
You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. You may not use the material for commercial purposes. Exportado de SIDERAL (2026-04-10-13:47:12)
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Record created 2026-04-10, last modified 2026-04-10