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1.
Silylation of cellobiose as a model reaction for the synthesis of silylated cellulose : a DFT and PM3 approach
Stefan 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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Future Perspectives in Polysaccharide Research
2016, druge monografije in druga zaključena dela

Ključne besede: polysaccharides, polysaccharide based materials
Objavljeno: 19.09.2016; Ogledov: 533; Prenosov: 34
.pdf Celotno besedilo (1,90 MB)

4.
A facile lab scale synthesis of red selenium
Ebels Jörg, Stefan Spirk, Rudolf Pietschnig, 2006, objavljeni znanstveni prispevek na konferenci

Ključne besede: analytical chemistry
Objavljeno: 22.06.2017; Ogledov: 266; Prenosov: 220
.pdf Celotno besedilo (327,78 KB)
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5.
NMR properties of SePPh3 in the solid state
Stefan Spirk, Rudolf Pietschnig, 2006, objavljeni znanstveni prispevek na konferenci

Ključne besede: analytical chemistry, isomers, stability, phosphorus
Objavljeno: 22.06.2017; Ogledov: 263; Prenosov: 212
.pdf Celotno besedilo (330,10 KB)
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6.
Photoregeneration of trimethylsilyl cellulose as a tool for microstructuring ultrathin cellulose supports
Archim 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
.pdf Celotno besedilo (886,41 KB)
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7.
Synthesis and structure of transition metal bisalkinylselenolato complexes
Rudolf Pietschnig, Carmen Moser, Stefan Spirk, Sven Schäfer, 2005, objavljeni znanstveni prispevek na konferenci

Opis: We synthesized closely related cis and trans platinum complexes of SeCC-n-C5H11 and elucidated their structures in solution and the crystalline state. In line with previous work we find exclusive coordination of the selenium atom of the ambident alkynylselenolate ligand and a preference for the obviously more stable trans isomer. In contrast to previous work we find auniform increase of all metal ligand bond lengths in the cis vs. the trans isomers. Moreover we studied the coordination of alkynykselenolate ligands to group 4 metals.
Ključne besede: analytical chemistry, isomers, stability, metals
Objavljeno: 22.06.2017; Ogledov: 267; Prenosov: 172
.pdf Celotno besedilo (614,73 KB)
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