Department of Chemistry
Synthesis, light-emitting, and two-photon absorption properties of platinum-containing poly(arylene-ethynylene)s linked by 1,3,4-oxadiazole units
A series of soluble and thermally stable group 10 platinum(II) polyyne polymers of the type [-C≡C-Pt(PBu3)2-C≡C-Ar- Ox-Ar-]n (where Ox = 1,3,4-oxadiazole; Ar = p-C6H 4 or 2,7-dihexyl-9,9-fluorene) and [-C≡C-Pt(PBu 3)2-C≡C-Ar-Ox-Ar-Ox-Ar-]n (where Ar = 2,7-dihexyl-9,9-fluorene) along with their corresponding dinuclear model compounds [Ph-Pt(PEt3)2-C≡C-Ar-]2-Ox- (where Ar = p-C6H4 or 2,7-dihexyl-9,9-fluorene) and [Ph-Pt(PEt3)2-C≡C-Ar-Ox-]2-Ar- (where Ar = 2,7-dihexyl-9,9-fluorene) were prepared and characterized. The regiochemical structure of the polymers has been ascertained by single-crystal X-ray analysis on the model compound [Ph-Pt(PEt3)2-C≡C-p-C 6H4-]2-Ox-. The photophysical properties (absorption, excitation, emission, and nanosecond transient absorption spectra) of these metalated compounds in 2MeTHF at 298 and 77 K are reported. These findings are correlated by density functional theory (DFT) calculations. Geometry optimizations predict totally planar molecules for these metalated complexes and polymers, allowing better π-conjugation across the main chain. The ligands are strongly fluorescent but become also phosphorescent when the Pt atom is introduced in the backbone of the conjugated organometallic complexes and polymers. These emissions are assigned to ππ* transitions in all cases involving the Pt dxy orbitals. These Pt compounds exhibit two-photon absorption (2PA), and their 2PA cross sections (σ2) have been determined. The potential of exploiting such metallopolymers for the design of electrophosphorescent polymer light-emitting devices (PLEDs) and their use as single-dopant for white PLEDs have also been discussed. © 2010 American Chemical Society.
Source Publication Title
American Chemical Society
Goudreault, Thomas, Ze He, Yanhe Guo, Cheuk-Lam Ho, Hongmei Zhan, Qiwei Wang, Keith Yat-Fung Ho, Ka-Leung Wong, Daniel Fortin, Bing Yao, Zhiyuan Xie, Lixiang Wang, Wai-Ming Kwok, Pierre D. Harvey, and Wai-Yeung Wong. "Synthesis, light-emitting, and two-photon absorption properties of platinum-containing poly(arylene-ethynylene)s linked by 1,3,4-oxadiazole units." Macromolecules 43.19 (2010): 7936-7949.