Silylation of cellobiose as a model reaction for the synthesis of silylated cellulose : a DFT and PM3 approachStefan Spirk
, Heike M. A. Ehmann
, Volker Ribitsch
, Karin Stana-Kleinschek
, 2011, objavljeni znanstveni prispevek na konferenci
Opis: The object of the present study is the isodesmic reaction of cellobiose (the repeating unit in cellulose) with different kinds of silanes, R-SiH3, to form silylated cellobiose (Cello-SiH3) and the corresponding alcohols (R-OH). The size and the chemical reactivity of the substituent R is varied as well as the position where O-silylation at the cellobiose takes place. In contrast to experimental observations where the O6 position is favored for silylation, for the computed reactions, energy differences are smaller than 3 kcal/mol for the different positions at the B3LYP/6-311G* as well as at the B3LYP/6-311+G* level of theory. Depending on the silane, reaction energies in a range from -17 kcal/mol (R=NHSiH3) and +18 kcal/mol (R=F) have been calculated. In addition, semi-empirical calculations on the PM3 level of theory have been performed. These results are set into contrast with the results derived from DFT calculations to assess whether semi-empirical methods may be useful for the description of larger systems containing silylated cellobiose units.
Ključne besede: silylation of cellobiose, silanes, DFT, PM3
Objavljeno: 01.06.2012; Ogledov: 1179; Prenosov: 36
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Photoregeneration of trimethylsilyl cellulose as a tool for microstructuring ultrathin cellulose supportsArchim Wolfberger
, Rupert Kargl
, Thomas Grießer
, Stefan Spirk
, 2014, izvirni znanstveni članek
Opis: Microstructured thin films based on cellulose, the most abundant biopolymer on Earth, have been obtained by UV-irradiation of acid-labile trimethylsilyl cellulose thin films in the presence of N-hydroxynaphtalimide triflate as photoacid generator. We demonstrate that this photoregeneration process can be exploited for the manufacture of cellulose patterns having feature sizes down to 1 μm, with potential applications in life sciences.
Ključne besede: cellulose thin films, cellulose regeneration, patterning of cellulose, photoregeneration
Objavljeno: 22.06.2017; Ogledov: 393; Prenosov: 246
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