title: Block modification of rod-shaped pi conjugated carbon frameworks with donor and acceptor groups toward highly fluorescent molecules: synthesis and emission characteristics.
abstract: To create organic molecules that are highly fluorescent at a longer wavelength region, we investigated the synthesis (using Pd-catalyzed cross-coupling) and photophysical properties (Phi(f), lambda(em), tau, lambda(abs), and epsilon) of the following pi conjugated molecular rods consisting of p-phenyleneethynylene units modified by donor (OMe) and/or acceptor (CN) groups: (1) side-donor modification systems (SD systems), (2) side-acceptor modification systems (SA systems), and (3) systems consisting of a donor block and an acceptor block (BL systems). As a consequence, very high Phi(f) values (>0.95) were obtained for BL systems. Bathochromic shifts of lambda(em) for the same pi conjugation length were largest for BL systems. Thus we succeeded in creating highly efficient light emitters at a longer wavelength region by block modification (e.g., Phi(f) = 0.97, lambda(em) = 464 nm for ). Considerably intense solid emission (Phi(f) approximately 0.5) at a longer wavelength region (500-560 nm) was also found for BL systems. It has been found that and exhibit interesting two photon absorption characteristics.
authors: Department of Chemistry, Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan.
authors: Takanori
authors: T
authors: Ochi
authors: Yoshihiro
authors: Y
authors: Yamaguchi
authors: Tateaki
authors: T
authors: Wakamiya
authors: Yoshio
authors: Y
authors: Matsubara
authors: Zen-Ichi
authors: Z
authors: Yoshida
mesh_terms: D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D049449:Luminescence; D015394:Molecular Structure; D009930:Organic Chemicals / Q000138:chemical synthesis / Q000737:chemistry*; D010777:Photochemistry
chemical_list: D005456:Fluorescent Dyes; D009930:Organic Chemicals