title: Photoreductive generation of amorphous bismuth nanoparticles using polysaccharides--bismuth-cellulose nanocomposites.
abstract: A simple and highly reproducible synthesis of amorphous bismuth nanoparticles incorporated into a polysaccharide matrix using a photoreduction process is presented. As precursor for the generation of the Bi nanoparticles, organosoluble triphenylbismuth is used. The precursor is dissolved in toluene and mixed with a hydrophobic organosoluble polysaccharide, namely trimethylsilyl cellulose (TMSC) with high DSSi. The solution is subjected to UV exposure, which induces the homolytic cleavage of the bismuth-carbon bond in BiPh3 resulting in the formation of Bi(0) and phenyl radicals. The aggregation of the Bi atoms can be controlled in the TMSC matrix and yields nanoparticles of around 20 nm size as proven by TEM. The phenyl radicals undergo recombination to form small organic molecules like benzene and biphenyl, which can be removed from the nanocomposite after lyophilization and exposure to high vacuum. Finally, the TMSC matrix is converted to cellulose after exposure to HCl vapors, which remove the trimethylsilyl groups from the TMSC derivative. Although TMSC is converted to cellulose, the formed TMS-OH is not leaving the nanocomposite but reacts instead with surface oxide layer of the Bi nanoparticles to form silylated Bi nanoparticles as proven by TEM/EDX.
authors.affiliation: Institute for Chemistry, University of Graz, Heinrichstrasse 24, 8010 Graz, Austria.
authors.forename: Doris
authors.initials: D
authors.lastname: Breitwieser
authors.affiliation: Johannes-Kepler-University Linz, Institute of Inorganic Chemistry, Altenbergerstraße 69, 4040 Linz, Austria.
authors.forename: Margit
authors.initials: M
authors.lastname: Kriechbaum
authors.affiliation: Institute for Chemistry, University of Graz, Heinrichstrasse 24, 8010 Graz, Austria.
authors.forename: Heike M A
authors.initials: HM
authors.lastname: Ehmann
authors.affiliation: Johannes-Kepler-University Linz, Institute of Inorganic Chemistry, Altenbergerstraße 69, 4040 Linz, Austria.
authors.forename: Uwe
authors.initials: U
authors.lastname: Monkowius
authors.affiliation: "Petru Poni" Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania.
authors.forename: Sergiu
authors.initials: S
authors.lastname: Coseri
authors.affiliation: "Petru Poni" Institute of Macromolecular Chemistry, Aleea Grigore Ghica Voda 41A, 700487 Iasi, Romania. Electronic address: livius@icmpp.ro.
authors.forename: Liviu
authors.initials: L
authors.lastname: Sacarescu
authors.affiliation: Graz University of Technology, Institute for Chemistry and Technology of Materials, Stremayrgasse 9, 8010 Graz, Austria; University of Maribor, Institute for the Engineering and Design of Materials, Smetanova Ulica 17, 2000 Maribor, Slovenia. Electronic address: stefan.spirk@tugraz.at.
authors.forename: Stefan
authors.initials: S
authors.lastname: Spirk
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D014297:Trimethylsilyl Compounds / Q000737:chemistry*
chemical_list: D014297:Trimethylsilyl Compounds; D002482:Cellulose; D001729:Bismuth
keywords: Bismuth nanoparticles; Cellulose; Photochemistry; Photoreduction; Trimethylsilyl cellulose