The photolysis of dichlorotriphenylbismuth(V) in chloroform.
Under 254 nm irradiation in chloroform, Bi(C6H5)3Cl2 reacts to yield HBiCl4 and H2BiCl5, in contrast to its behavior in acetonitrile, in which bismuth metal appears to be the eventual product, unless anhydrous HCl is present, in which case H2BiCl5 is also formed. The photolysis in CHCl3 is not significantly solvent-initiated. The rate depends directly on the light intensity absorbed by the metal complex, and the quantum yield is 0.026. In CCl4 a portion of the reaction occurs through absorption of light by the solvent.
Photoreductive generation of amorphous bismuth nanoparticles using polysaccharides--bismuth-cellulose nanocomposites.
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.
Radiochemische Untersuchungen an Quecksilber-Kohlenstoff-Verbindungen
Unsymmetrische quecksilberorganische Verbindungen des Typs R Hg R′ wurden bei −20° in atherischen Losungen mit 203HgBr2 (Molverhaltnis 1:1) umgesetzt. Die Bestimmung der Verteilung des radioaktiven Quecksilbers auf die Reaktionsprodukte R Hg Br und R′ Hg Br zeigt, das die Haftfestigkeit des organischen Restes am Quecksilberatom bei aliphatischen Verbindungen mit wachsender Kettenlange des Restes zunimmt. Bei aromatischen Quecksilber-Kohlenstoff-Verbindungen des Typs R Hg R′ ist die Spaltung derjenigen Hg C-Bindung erschwert, die durch Doppelbindungsanteile stabilisiert werden kann.