The generation of patterned images in polymer films has been extensively studied and used in fundamental and applied research areas. The development of patterned color or fluorescent images, especially, is of great technological importance in the electronics industry. Recently, the generation of functional images by selective immobilization of organic dyes in the polymer film has been reported. [1±3] Selective removal of acid-labile protecting groups through photoinduced chemical transformation followed by chemisorption of organic dyes from solution into the patterned polymer film has given micrometer-scale functional images. The two-step procedures described in the literature, however, have potential problems such as difficulty of dye penetration into polymer matrices and concern about longterm stability of the patterned images.To avoid these limitations, we have tried to develop a direct method of generating fluorescence images with a precursor molecule. The strategic basis for designing a precursor is that the precursor molecule is non-fluorescent and/or colorless, but becomes fluorescent and/or reveals color by photoinduced chemical changes. We have previously reported that the UV absorption maximum and fluorescence of quinizarin 1 can be readily altered and manipulated simply by blocking the intramolecular hydrogen bonds. [4] Thus, the UV absorption maximum (479 nm) of quinizarin 1 shifts to a shorter wavelength (335 nm) on blocking the two phenols with two tert-butoxycarbonyl (t-BOC) groups. In addition, the t-BOC-protected quinizarin 2 has virtually no fluorescence, whereas quinizarin 1 is strongly fluorescent due to the quasi-aromatic structure caused by intramolecular hydrogen bonding. As a part of our continuing interest in the generation of relief and functional images with transiently protected precursor molecules in polymer films, we now report the synthesis of a novel polymer having t-BOC-protected quinizarin moieties and the genera-tion of color and fluorescent images by photolithographic methods. To our knowledge, this is the first example of finely resolved fluorescent images with a polymer having transiently protected precursor pendants.The strategies employed for the synthesis of t-BOC-protected quinizarin monomer 7 are shown in Scheme 1. Aldol condensation of leucoquinizarin (3) with 5-(benzyloxy)pentanal (4) [5] in the presence of piperidinium acetate in 2-propanol under Marschalk conditions [6] readily afforded the key intermediate, 2-substituted quinizarin 5, in an excellent yield (96 %). The intermediate 5, obtained as a pale red solid, has strong fluorescence due to intramolecular hydrogen bonding, confirming the proposed structure. Protection of the two phenol groups of 5 with di-tert-butyl dicarbonate in the presence of a catalytic amount of 4-dimethylaminopyridine (DMAP) in tetrahydrofuran (THF) provided the t-BOC-protected 2-substituted quinizarin 6 in 92 % yield. The fluorescence is virtually eliminated in the t-BOC-protected intermediate 6 and the position of the UV absorp-[**] We...

The generation of patterned images in polymer films has been extensively studied and used in fundamental and applied research areas. The development of patterned color or fluorescent images, especially, is of great technological importance in the electronics industry. Recently, the generation of functional images by selective immobilization of organic dyes in the polymer film has been reported. [1±3] Selective removal of acid-labile protecting groups through photoinduced chemical transformation followed by chemisorption of organic dyes from solution into the patterned polymer film has given micrometer-scale functional images. The two-step procedures described in the literature, however, have potential problems such as difficulty of dye penetration into polymer matrices and concern about longterm stability of the patterned images.To avoid these limitations, we have tried to develop a direct method of generating fluorescence images with a precursor molecule. The strategic basis for designing a precursor is that the precursor molecule is non-fluorescent and/or colorless, but becomes fluorescent and/or reveals color by photoinduced chemical changes. We have previously reported that the UV absorption maximum and fluorescence of quinizarin 1 can be readily altered and manipulated simply by blocking the intramolecular hydrogen bonds.[4] Thus, the UV absorption maximum (479 nm) of quinizarin 1 shifts to a shorter wavelength (335 nm) on blocking the two phenols with two tert-butoxycarbonyl (t-BOC) groups. In addition, the t-BOC-protected quinizarin 2 has virtually no fluorescence, whereas quinizarin 1 is strongly fluorescent due to the quasi-aromatic structure caused by intramolecular hydrogen bonding. As a part of our continuing interest in the generation of relief and functional images with transiently protected precursor molecules in polymer films, we now report the synthesis of a novel polymer having t-BOC-protected quinizarin moieties and the generation of color and fluorescent images by photolithographic methods. To our knowledge, this is the first example of finely resolved fluorescent images with a polymer having transiently protected precursor pendants. The strategies employed for the synthesis of t-BOC-protected quinizarin monomer 7 are shown in Scheme 1. Aldol condensation of leucoquinizarin (3) with 5-(benzyloxy)pentanal (4) [5] in the presence of piperidinium acetate in 2-propanol under Marschalk conditions [6] readily afforded the

Fluorescent images can be photochemically generated in thin films of the copolymer 1. This fluorescent copolymer has been designed in such a way that interaction with a photochemically formed acid HA, leading to the protonated species, quenches the fluorescence. When this quenching occurs in selected areas patterned images are obtained.

No abstract

Fluoreszierende Bilder lassen sich photochemisch in dünnen Filmen des Copolymers 1 erzeugen. Dieses fluoreszierende Copolymer wurde so konzipiert, dass die Wechselwirkung mit einer photochemisch generierten Säure HA, aus der die protonierte Spezies resultiert, die Fluoreszenz löscht. Wenn dieses Löschen in ausgewählten Bereichen passiert, entstehen Muster.