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Luminescent Platinum(II) Complexes Containing Cyclometallated Diaryl Ketimine Ligands: Synthesis, Photophysical and Computational Properties

Pandya, SU; Moss, KC; Bryce, MR; Batsanov, AS; Fox, MA; Jankus, V; Al Attar, HA; Monkman, AP

Authors

SU Pandya

KC Moss

MR Bryce

AS Batsanov

V Jankus

HA Al Attar



Abstract

A new series of platinum(II) complexes containing cyclometallated diaryl ketimine ligands has been synthesised. The route involves reaction of diaryl ketimines with K[PtCl3(dmso)] to obtain trans-[PtCl2(imine)(dmso)] species, which underwent cyclometallation upon heating in toluene to give [PtCl{Ar′(ArC=NH)}(dmso)] complexes 12b–17b. N-Hydroxy and N-phenyl analogues 18b and 21 were also synthesised. In complexes 19 and 20 the auxiliary chlorido and dmso ligands were replaced by an acetylacetonato ligand. The photophysical properties of the cyclometallated complexes are reported. The emission bands at λmax ≈ 450 and 550 nm are assigned to mixed-ligand and MLCT states having significant singlet and triplet character, respectively. By varying the structure of the aromatic ligand the efficiency of phosphorescence can be increased to 4.3 % for 15b (Ar′ = 1-naphthyl). Theoretical calculations show that the low-energy transitions in all the cyclometallated systems involve mainly the frontier orbitals, HOMO and LUMO. These are mixed chlorido–metal–ligand to largely π*-C=N transitions. Most of the observed phosphorescence data can be explained by the geometric change on going from the S0 to the T1 states. An organic light-emitting device has been fabricated by using complex 15b as the emissive dopant in a poly(vinylcarbazole) host. Broad electroluminescence spanning the range 500–750 nm was observed.

Citation

Pandya, S., Moss, K., Bryce, M., Batsanov, A., Fox, M., Jankus, V., …Monkman, A. (2010). Luminescent Platinum(II) Complexes Containing Cyclometallated Diaryl Ketimine Ligands: Synthesis, Photophysical and Computational Properties. European Journal of Inorganic Chemistry, 2010(13), 1963-1972. https://doi.org/10.1002/ejic.200901159

Journal Article Type Article
Publication Date May 1, 2010
Deposit Date Dec 14, 2011
Journal European Journal of Inorganic Chemistry
Print ISSN 1434-1948
Electronic ISSN 1099-0682
Publisher Wiley-VCH Verlag
Peer Reviewed Peer Reviewed
Volume 2010
Issue 13
Pages 1963-1972
DOI https://doi.org/10.1002/ejic.200901159
Keywords Platinum, Complexation, Cyclometallation, Photoluminescence, Density functional calculations, Light-emitting devices.