132944-37-7Relevant academic research and scientific papers
Cyclometalated platinum(II) 6-phenyl-4-(9,9-dihexylfluoren-2-yl)-2, 2′-bipyridine complexes: Synthesis, photophysics, and nonlinear absorption
Shao, Pin,Li, Yunjing,Yi, Jing,Pritchett, Timothy M.,Sun, Wenfang
scheme or table, p. 4507 - 4517 (2010/07/04)
A series of mononuclear and dinuclear cyclometalated platinum(II) 6-phenyl-4-(9,9-dihexylfluoren-2-yl)-2,2′-bipyridine complexes (F-1-F-5) were synthesized and their photophysical properties were systematically investigated. All complexes exhibit strong 1π, π*absorption bands in the UV region, and a broad, structureless charge transfer band in the visible region. The charge-transfer band is broadened and red-shifted for F-3-F-5 compared to those for F-1 and F-2 because of the electron-donating acetylide ligand and the involvement of the ligand-to-ligand charge transfer character. The molar extinction coefficients for the dinuclear complex F-5 are much higher than those for the mononuclear complexes F-1-F-4, indicating the electronic coupling through the bridge ligand. All complexes are emissive in solution at room temperature and in glassy matrix at 77 K. When excited at the charge transfer absorption band, the complexes exhibit a long-lived red/orange emission around 600 nm, which is attributed to a triplet metal-to-ligand charge transfer/intraligand charge transfer emission ( 3MLCT/3ILCT). For emission at 77 K, the emitting state is tentatively assigned as 3MLCT for F-2-F-4, and 3MLCT/ 3π,π*for F-1 and F-5 taking into account the emission energy, the shape of the spectrum, the lifetime, and the thermally induced Stokes shift. F-1-F-4 exhibit broad triplet transient difference absorption in the visible to the near-IR region, with a lifetime comparable to those measured from the decay of the 3MLCT/3ILCT emission. Therefore, F-1-F-4 give rise to a strong reverse saturable absorption for ns laser pulses at 532 nm. Z-scan experiments were carried out at 532 nm using both ns and ps laser pulses, and the experimental data was fitted by a five-band model to extract the singlet and triplet excited-state absorption cross sections. The degree of reverse saturable absorption follows this trend: F-1 = F-2 > F-3 > F-4 > F-5, which is mainly determined by the ratio of the triplet excited-state absorption cross-section to that of the ground-state and the triplet excited-state quantum yield. Comparison of the photophysics of F-1, F-2, and F-3 to those of their corresponding Pt complexes without the fluorenyl substituent discovers that F-1-F-3 exhibit larger molar extinction coefficients for their low-energy charge transfer absorption band, longer triplet excited-state lifetimes, higher emission quantum yields, and increased ratios of the excited-state absorption cross-section to that of the ground-state.
Photophysics of Pt(II) 4,6-diphenyl-2,2′-bipyridyl complexes in solution and in LB film
Mathew, Iswarya,Sun, Wenfang
experimental part, p. 2750 - 2756 (2009/12/06)
Two amphiphilic platinum(II) 4,6-diphenyl-2,2′-bipyridyl complexes (1 and 2) were synthesized and characterized. LB films of these two complexes were prepared and characterized by AFM technique. Electronic absorption and emission characteristics of these
