Synthesis and lithographic applications of highly metallized cluster-based polyferrocenylsilanes

We report the use of a cobalt-clusterized polyferrocenylsilane (Co-PFS) as a precursor to patterned ferromagnetic ceramics. Co-PFS was synthesized. Functioning as a negative resist, Co-PFS lines with widths of 10-300 μm were patterned using UV-photolithography, while features as small as 500 nm were afforded by electron-beam lithography. Subsequent pyrolytic treatment of the lithographically patterned Co-PFS yielded ferromagnetic ceramics containing Fe/Co nanoparticles. Due to its high metal-loading, Co-PFS is a good etch resist for oxygen and hydrogen plasma reactive ion etching. Reactive ion etching of a thin film of Co-PFS in a secondary magnetic field allowed direct access to ferromagnetic ceramic films, providing a viable alternative to pyrolysis.     

ChemInform Abstract: Ligand Dependence of Metal—Metal Bonding in the d3d3 Dimers M2X9n- (MIII: Cr,Mo, W; MIV: Mn,Tc, Re; X: F,Cl, Br,I)

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

The changing biochemical composition and organisation of the murine oocyte and early embryo as revealed by Raman spectroscopic mapping

Despite an exponential uptake in recent years of assisted reproductive techniques, such as in vitro fertilisation, much is still not fully understood about the biochemical modifications that take place during the development and maturation of the egg and embryo. As such, in order to improve the efficiency of these techniques, furthering our understanding of the processes that underpin oocyte and embryo development is necessary. Raman spectroscopic mapping as a technique enables the investigation of biochemical variation within intact cells without the need for labelling. Here, Raman maps of fixed immature and mature oocytes along with early stage embryos were collected using 785 nm excitation and a step size of 2 µm. The results were analysed using both univariate and multivariate techniques. It was found that significant macromolecular accumulation took place during oocyte maturation, while a decrease in total lipid content consistent with the formation of new cellular membranes is observed upon embryo cleavage. Furthermore, an observed asymmetrical localisation of macromolecules in the mature oocyte may indicate the existence of cytoplasmic polarisation, a phenomenon that has been observed in the eggs of lower organisms. As such, these results indicate that Raman spectroscopic mapping may present an alternative analytical tool for investigating the biochemistry of egg and embryo development. In particular, these results indicate that temporal Raman analysis may help to reveal the existence of cytoplasmic polarisation in the murine egg. Copyright © 2011 John Wiley & Sons, Ltd.