title: Synthesis and characterization of luminescent cyclometalated platinum(II) complexes of 1,3-bis-hetero-azolylbenzenes with tunable color for applications in organic light-emitting devices through extension of π conjugation by variation of the heteroatom.
abstract: A series of luminescent cyclometalated platinum(II) complexes of N^C^N ligands [N^C^N=2,6-bis(benzoxazol-2'-yl)benzene (bzoxb), 2,6-bis(benzothiazol-2'-yl)benzene (bzthb), and 2,6-bis(N-alkylnaphthoimidazol-2'-yl)benzene (naphimb)] has been synthesized and characterized. Two of the platinum(II) complexes have been structurally characterized by X-ray crystallography. Their electrochemical, electronic absorption, and luminescence properties have been investigated. In dichloromethane solution at room temperature, the cyclometalated N^C^N platinum(II) complexes exhibited rich luminescence with well-resolved vibronic-structured emission bands. The emission energies of the complexes are found to be closely related to the electronic properties of the N^C^N ligands. By varying the electronic properties of the cyclometalated ligands, a fine-tuning of the emission energies can be achieved, as supported by computational studies. Multilayer organic light-emitting devices have been prepared by utilizing two of these platinum(II) complexes as phosphorescent dopants, in which a saturated yellow emission with Commission International de I'Eclairage coordinates of (0.50, 0.49) was achieved.
authors.affiliation: Department of Chemistry, The University of Hong Kong, Pokfulam Road (Hong Kong), Fax: (+852) 2857-1586.
authors.forename: Alan Kwun-Wa
authors.initials: AK
authors.lastname: Chan
authors.forename: Elizabeth Suk-Hang
authors.initials: ES
authors.lastname: Lam
authors.forename: Anthony Yiu-Yan
authors.initials: AY
authors.lastname: Tam
authors.forename: Daniel Ping-Kuen
authors.initials: DP
authors.lastname: Tsang
authors.forename: Wai Han
authors.initials: WH
authors.lastname: Lam
authors.forename: Mei-Yee
authors.initials: MY
authors.lastname: Chan
authors.forename: Wing-Tak
authors.initials: WT
authors.lastname: Wong
authors.forename: Vivian Wing-Wah
authors.initials: VW
authors.lastname: Yam
keywords: cyclometalation; density functional theory calculation; luminescence; organic light-emitting diodes; platinum