The Use of Cyclometalated NHCs and Pyrazoles for the Development of Fully Efficient Blue PtII Emitters and Pt/Ag Clusters

Arnal, L. ; Fuertes, S. ; Martín, A. (Universidad de Zaragoza) ; Sicilia, V. (Universidad de Zaragoza)

Resumen: New bis-pyrazole complexes [Pt(C^C*)(RpzH)2]X, containing a cyclometalated N-heterocyclic carbene ligand (HC^C*=1-(4-(ethoxycarbonyl)phenyl)-3-methyl-1H-imidazol-2-ylidene) were prepared as chloride (X=Cl-, RpzH: 3,5-Me2pzH 1¿a, 4-MepzH 2¿a, pzH 3¿a), perchlorate (X=ClO4-, 1¿b–3¿b), or hexafluorophosphate (X=PF6-, RpzH: 3,5-Me2pzH 1¿c) salts. The X-ray structure of 1¿a showed that the Cl- anion is trapped by the cation through two N-H···Cl bonds. In solution of methanol, acetone and THF at RT, 1¿a–3¿a coexist in equilibrium with the corresponding [PtCl(C^C*)(RpzH)] (B) and RpzH species. In CH2Cl2, this equilibrium takes place just for 2¿a and 3¿a, but it is completely shifted to the left at 243 and 223 K for 2¿a and 3¿a, respectively. The low-lying absorption and emission bands were assigned to intraligand (ILCT) charge transfer on the NHC group. Quantum yield measurements in PMMA films revealed that 1¿b, 2¿b and 1¿c are amongst the most efficient blue-light emitters, with values up to 100¿%. Proton abstraction from the coordinated 3,5-Me2pzH in 1¿b by NEt3 and replacement by Ag+ afforded a neutral [Pt2Ag2] cluster containing Pt¿Ag dative bonds.

Idioma: Inglés

DOI: 10.1002/chem.201800646

Año: 2018

Publicado en: Chemistry - A European Journal 24, 37 (2018), 9377-9384
ISSN: 0947-6539

Factor impacto JCR: 5.16 (2018)

Categ. JCR: CHEMISTRY, MULTIDISCIPLINARY rank: 36 / 172 = 0.209 (2018) - Q1 - T1

Factor impacto SCIMAGO: 1.842 - Catalysis (Q1) - Organic Chemistry (Q1) - Chemistry (miscellaneous) (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E21
Financiación: info:eu-repo/grantAgreement/ES/MINECO-FEDER/CTQ2015-67461-P

Tipo y forma: Artículo (PostPrint)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)