860435-89-8Relevant academic research and scientific papers
Two-photon induced emissive thiophene donor-acceptor systems as molecular probes for in vitro bio-imaging: Synthesis, crystal structure, and spectroscopic properties
Chow, Cheuk-Fai
, p. 18835 - 18843 (2013)
Two new classes of organic two-photon absorption (TPA) chromophores, D-π-A (Bt1/Tt1) and D-π-A-π-D (Bt 2/Tt2), were designed and synthesized using a Sonogashira coupling reaction between 4-ethynyl-N,N-dimethylaniline and 5′-bromo-2, 2′-bithiophene/2,2′:5′,2′′-terthiophene or 5,5′-dibromo-2,2′-bithiophene/2,2′:5′, 2′′-terthiophene, respectively. At room temperature, all of the compounds had single-photon fluorescent and solvatochromatic properties, and could produce two-photon-induced luminescence upon excitation at 700 nm (Ti:sapphire femtosecond laser, 150 fs pulses). The corresponding TPA cross-section values ranged from 81 to 563 GM (10-50 cm4 s photon-1 molecule-1). The quadrupolar-type (D-π-A-π-D) chromophores, Bt2 and Tt2, exhibited a larger TPA cross-section (σ2) value than their dipolar analogues (D-π-A), Bt1 and Tt1, whereas the bithiophene chromophores, Bt1 and Bt2, exhibited a larger σ2 value than their terthiophene counterparts, Tt1 and Tt2. All of the compounds were used for bio-imaging in living human cervical carcinomas (HeLa). We found that Bt1 and Tt 1 were able to pass through the cell membrane and to selectively stain the cell cytoplasm and lysosome, respectively. The results of these studies could provide new molecular-design strategies for two-photon imaging in vitro. The Royal Society of Chemistry 2013.
