Nickel sulfide thin films and nanocrystals stabilized with oleylamine ligands are prepared from two different nickel xanthates as single-source precursors, which decompose at approx. 180°C, and are thereby converted into nickel sulfide. These nickel xanthates comprise branched alkyl moieties allowing the choice of a wide range of nonpolar organic solvents for the processing to nickel sulfide thin films as well as to nanoparticles. The crystal structures of both compounds show a typical square-planar coordination of the sulfur atoms of both xanthates to the nickel central atom. The thermal decomposition via the Chugaev reaction forming nickel sulfide was studied by thermal gravimetric analysis showing the reaction taking place at about 180°C. Consequently, by thermally converting spin-coated metal xanthate films directly on the substrates in the solid state, thin films consisting of hexagonal nickel sulfide are formed. If the nickel xanthates are heated in an oleylamine solution, oleylaminecapped nickel sulfide nanocrystals are obtained, exhibiting hexagonal NiS as main phase and Ni 3 S 4 as secondary phase. This is also reflected in a sulfur-rich composition of the synthesized nickel sulfide nanocrystals as observed from TEM-EDX analyses.

Nitrile hydratases (NHase) catalyze the hydration of nitriles to the corresponding amides. We report on the heterologous expression of various nitrile hydratases. Some of these enzymes have been investigated by others and us before, but sixteen target proteins represent novel sequences. Of 21 target sequences, 4 iron and 16 cobalt containing proteins were functionally expressed from Escherichia coli BL21 (DE3) Gold. Cell free extracts were used for activity profiling and basic characterization of the NHases using the typical NHase substrate methacrylonitrile. Co-type NHases are more tolerant to high pH than Fe-type NHases. A screening for activity on three structurally diverse nitriles was carried out. Two novel Co-dependent NHases from Afipia broomeae and Roseobacter sp. and a new Fe-type NHase from Gordonia hydrophobica were very well expressed and hydrated methacrylonitrile, pyrazine-carbonitrile, and 3-amino-3-(p-toluoyl)propanenitrile. The Co-dependent NHases from Caballeronia jiangsuensis and Microvirga lotononidis, as well as two Fe-dependent NHases from Pseudomonades, were—in addition—able to produce the amide from cinnamonitrile. Summarizing, seven so far uncharacterized NHases are described to be promising biocatalysts.