A novel family of functionalized styrenic copolymers that are susceptible to a base-catalyzed β-elimination reaction is reported. The reactive copolymers, poly-{(2-phenyl-2-cyanoethoxycarbonyloxystyrene)-co-(4-hydroxystyrene)}, are prepared by chemical modification of poly(4-hydroxystyrene) using 2-phenyl-2-cyanoethyl chloroformate. A photoresist material consisting of the copolymer and bis[[(2-nitrobenzyl)-oxy] carbonyl]-4,4′-trimethylenedipiperidine used as an amine photogenerator affords positive tone images by UV irradiation. The effect of copolymer structure and composition on imaging, thermal stability, and the ease of β-elimination reaction is discussed. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3543–3552 1997

The kinetics of the amine catalyzed intramolecular imidization of alkyl and phenyl phthalamates with a variety of amines were measured in deuteriated chloroform at 40.1 °C. An overall second-order kinetic rate law, rate =koverall[amine][phthalamate], was obtained from our experiments. Although pre-association between the amides and the amines through hydrogen-bonding interaction was suggested by proton NMR spectroscopy, the catalytic ability of amines was found to be related to their basicity rather than to their hydrogen-bonding ability or nucleophilicity. This observation implies the involvement of proton transfer from the amide to the amine in the critical transition state. In addition, by changing the leaving group from phenoxy to butoxy group, the reaction rate constants decrease by a factor of 30 to 70. On the basis of these kinetic results, we propose that the intramolecular imidization proceeds through an amine assisted cyclization to a zwitterionic intermediate, followed by the expulsion of the alkoxy or phenoxy group to provide phthalimide and the corresponding alcohol.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUse of polymeric catalysts in the pore-size-specific functionalization of porous polymersVladimir Smigol, Frantisek Svec, and Jean M. J. FrechetCite this: Macromolecules 1993, 26, 21, 5615–5620Publication Date (Print):October 1, 1993Publication History Published online1 May 2002Published inissue 1 October 1993https://pubs.acs.org/doi/10.1021/ma00073a013https://doi.org/10.1021/ma00073a013research-articleACS PublicationsRequest reuse permissionsArticle Views353Altmetric-Citations46LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

We have previously shown that a copolymer of p-hydroxstyrene and p-acetoxymethylstyrene can be used as a sensitive deep UV resist. In that study we demonstrated that a formulation of this copolymer and an onium salt could be exposed, baked and developed in aqueous base to yield a high resolution negative tone relief image. In this paper we discuss a gas phase silylation process that converts this negative tone solvent-developable resist system into a positive tone dry-developable resist system. We have used an FT-IR microscope, coupled to a motorized X-Y stage, to study the silylation process as a function of UV exposure dose and silylation processing parameters. By altering the copolymer ratio, we found that resist contrast increased when the amount of acetoxymethylstyrene increased. This resist system and dry develop process were used to print 0.35 micrometers images at a DUV dose of approximately 25 mJ/cm<SUP>2</SUP>.

Abstract Als Oxidationsmittel für Alkohole (II) bzw. (IV) kann ein polymeres Polyvinylpyridinchlorchromat (I) eingesetzt werden, das aus einem schwach vernetzten Polyvinylpyridin mit HCl und Chromsäureanhydrid erhalten wird.

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Abstract Monodispersed macroporous poly(styrene-divinylbenzene) particles in a 5-6 μm size range were prepared by a multi-step swelling and polymerization method with toluene as the porogenic solvent, and their properties were examined. The particles were found to possess relatively broad pore size distributions. HPLC columns packed with the monodispersed particles show good efficiencies and low column pressure drops in a reversed-phase chromatographic mode.

Acetolysis of 1,6-anhydro-2,3,4-tri-O-benzyl-β-D-galactopyranose (3) followed by de-O-acetylation and p-nitrobenzoylation gave 2,3,4-tri-O-benzyl-1,6-di-O-p-nitrobenzoyl-β-D-galactopyranose (4) which was converted into 2,3,4-tri-O-benzyl-6-O-p-nitrobenzoyl-α-D-galactopyranosyl bromide (5). Benzylation of methyl 4,6-O-benzylidene-α-D-galactopyranoside (6) gave the 2,3-dibenzyl ether (7) which was hydrolyzed to 2,3-di-O-benzyl-D-galactose (8). p-Nitrobenzoylation of 8 furnished 2,3-di-O-benzyl-1,5,6-tri-O-p-nitrobenzoyl-β-D-galactofuranose (9) and an isomer, presumably a β-pyranose derivative (10). Compound 9 was converted into 2,3-di-O-benzyl-5,6-di-O-p;-nitrobenzoyl-β-D-galactofuranosyl bromide (11) and chloride (12). The new halides 5, 11, and 12 as well as known 2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl bromide (1) and chloride (2) were subjected to methanolysis in dichloromethane solution in the presence of methanol alone and in the presence of tetrabutylammonium bromide, mercuric cyanide, and silver tetrafluoroborate, respectively, and the ratios of anomeric glycosides produced were examined by n.m.r. spectroscopy. Factors influencing stereoselectivity in these reactions are discussed. The new methyl α- and β-glycosides derived from 5 (13 and 14) and the methyl α-glycoside (15) produced from 11 and 12 were isolated, and methyl 2,3,5,6-tetra-O-benzyl-α-D-galactofuranoside (16) was prepared for the first time.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid-phase synthesis of oligosaccharides. II. Steric control by C-6 substituents in glucoside synthesesJean M. Frechet and Conrad SchuerchCite this: J. Am. Chem. Soc. 1972, 94, 2, 604–609Publication Date (Print):January 1, 1972Publication History Published online1 May 2002Published inissue 1 January 1972https://pubs.acs.org/doi/10.1021/ja00757a047https://doi.org/10.1021/ja00757a047research-articleACS PublicationsRequest reuse permissionsArticle Views410Altmetric-Citations98LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReaction of crosslinked chloromethyl polystyrene with 1,4-butanedithiol: site-site interactions and their controlM. Jean Farrall and Jean M. J. FrechetCite this: J. Am. Chem. Soc. 1978, 100, 25, 7998–7999Publication Date (Print):December 1, 1978Publication History Published online1 May 2002Published inissue 1 December 1978https://pubs.acs.org/doi/10.1021/ja00493a033https://doi.org/10.1021/ja00493a033research-articleACS PublicationsRequest reuse permissionsArticle Views182Altmetric-Citations44LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The design of resists based on the principle of chemical amplification has provided imaging materials with remarkable sensitivity. These materials all function on the basis of photo-generation of a latent image of catalyst. In a subsequent step that is usually thermally activated, the catalyst acts on some part of the formulation to modify the solubility of the film. In most cases reported to date, the systems depend on acid that is generated by the irradiation of neutral compounds which produce acidic radiolysis products. Acid catalysis of side chain cleavage, cross-linking, and hydrolysis are but a few of the reactions that have been exploited in the design of acid catalyzed, chemically amplified resists. This paper now reports the authors` work on the use of photo-generated base in the design of resists that derive high sensitivity from base catalyzed chemical transformations. A variety of base catalyzed reactions have been auditioned for this application.

A series of new polyfunctional latent electrophiles capable of acting as crosslinkers in the photoimaging of aromatic polymers has been prepared and tested in chemically amplified photoresist formulations. Extremely high sensitivities have been achieved with a variety of modes of irradiations: deep-UV (DUV) (ca. 0.1 - 0.3 mJ/cm<SUP>2</SUP>), E-beam (&lt; 1 (mu) C/cm<SUP>2</SUP>) and x ray (ca. 15 mJ/cm<SUP>2</SUP>). In some cases, the sensitivities of these materials are so high that they have surpassed the capabilities of many existing exposure tools, making it desirable to lower them. This can be achieved through the addition of an electron rich species to the resist formulations to partially capture the photogenerated acid. It was shown that there is a linear correlation between the amount of additive and the sensitivities of the resulting resists.

An acid catalysed rearrangement that transforms a bicyclic lactone into a phenolic carboxylic acid has been tested for potential use in chemically amplified microlithographic imaging.

Since the concept of chemical amplification was first introduced by us more that twelve years ago, a number of new resists based on acid-catalyzed thermolysis have been developed and commercialized. This report describes the first chemically amplified resist operating through photogenerated base. The concept is demonstrated with poly(2-cyano-2-(p-vinylphenyl)butanoic acid) which decarboxylates readily under basic conditions. A resist system consisting of this polymer and an amine photogenerator bis(2,6-dinitrobenzyloxy)carbonylhexan- 1,6-diamine has been formulated and tested in microlithography. The sensitivity of this resist is extremely high (1.4 mj/sq cm) with a very high contrast of 13. 7. This very high sensitivity confirms that chemical amplification is achieved as the photogenerated base is not consumed in the overall decarboxylation process. The mechanistic insights gained from the study of the decarboxylation process may be used in the designed of other resists involving more readily accessible polymers.