Phthalocyanine-Sensitized Generation of Silver Nanoparticles in Aqueous Buffer Solution Triggered by Red LED-Light.

Silver nanoparticles have been generated in aqueous buffer solution using a water-soluble silicon phthalocyanine sensitizer. Red light illumination (660 nm LED) was performed under aerobic conditions at ambient temperature in the presence of TEOA as a reductant. Structural characterization of the Ag nanoparticles formed was carried out by transmission electron microscopy (TEM). The resulting silver particles, depending on irradiation time and choice of procedure, were found to have a spheric shape and a narrow size distribution of 5-10 nm.

The use of cobalt-mediated cycloisomerisation of ynedinitriles in the synthesis of pyridazinohelicenes.

A cobalt-mediated [2+2+2] cycloisomerisation of ynedinitriles to helical pyridazines in good to high yields was developed. The construction of the pyridazine nucleus from one alkyne and two nitrile units is proposed to follow either a conventional organometallic mechanism or to be triggered by a single-electron transfer from a Co(II) species. Various [5]-, [6]- and [7]helicene pyridazines were prepared.