Synthesis And Characterizations Of Novel Benzylidene Cyclopentanone Dyes As Two-photon Photopolymerization Sensitizers

In this thesis, three series of benzylidene cyclopentanone dyes were designed and synthesized. Their photophysical and photochemical properties were studied systematically. Some valuable results were obtained.1 A series of asymmetrical benzylidene cyclopentanone dyes 1-5 were synthesized. All these compounds presented large two-photon absorption cross-sections in an order of 10-48 cm4 s molecule-1 photon-1 in the wavelength range of 700-880nm in chloroform. These cross-section values are among the largest values obtained for molecules of similar size with femtosecond pulses. Dyes containing stronger electron-donating groups exhibited more efficient sensitizing to the polymerization system than those with electron-withdrawing groups.2 A symmetrical benzylidene cyclopentanone compound 6 was synthesized based on dye BDMA by introducing of a styrene moiety. The TPA of compound 6 is enhanced by elongating the molecular conjugation structure. In addition, the compound presented high sensitizing efficiency matching to the commercial UV initiator Omnicat 820.3 Novel multi-branched benzylidene cyclopentanone dyes with a triphenylamine core were synthesized. The maximum TPA cross-sections obtained with femtosecond laser pulses was as high as 3298 GM. In addition, a cooperative enhancement effect of TPA in two- and three-branched dyes 8 and 9 was observed. Compared with the well-known dye BDMA, all three compounds presented quite larger TPA cross-sections and higher sensitizing efficiency matching with the commercial UV initiator Omnicat 820.4 The primary microfabrication experiments have been carried out and revealed our dyes/coinitiator system could effectively realize TPP. The polymerized three-dimensional periodical strucrures were obtained and the best resolution obtained was about 140 nm.5 A water-soluble inclusion complex BDEA-Me-CD was obtained by the complexation of Me-β-CD with the hydrophobic benzylidene cyclopentanone dye BDEA. The complex keeped good TPA ability and high photosensitizing efficiency matching with the initiator DPI-Me-CD (the complexation of Me-β-CD with the hydrophobic 4,4'-dimethyl diphenyliodonium salt). Microstructures were obtained with the water-soluble two-photon photosensitized initiating system using femtosecond laser.