The changes in the electronic absorption spectra (UV-Vis) of some metallocene-doped poly(methyl methacrylate) (PMMA) thin films containing chloroform molecules as impurities were studied after photoexcitation in the nitrogen atmosphere. Photoexcitations were made by monochromatic radiation (using a Xe-lamp source and a monochromator) at an interval of few nanometers in the spectral range 210-75...

This review article describes developments in chiral metallocenes as polymerization catalysts focusing on C2 symmetric ansa-zirconocene complexes. Selective synthesis of rac-isomers of ansa-zirconocenes are surveyed. Isospecific polymerizations of propylene catalyzed by chiral zirconocenes are summarized. Advanced series of polymerizations by chiral metallocenes such as asymmetric polymerizatio...

Electronic absorption and resonance Raman spectral studies of benzoylruthenocene (BRc) and 1,1'-dibenzoylruthenocene (DRc) indicate that the low-energy electronic excited states of these 4d(6) metallocenes possess metal-to-ligand charge transfer (MLCT) character. While this MLCT contribution should weaken the metal-ring bonding in the excited state, neither compound is photosensitive in nonhalo...

The binary mixtures of Cp2ZrMe2, Cp2ZrCl2, DMAC, TMA, and MAO have been studied by in situ IR spectroscopy in order to clarify the activation mechanism of metallocenes with MAO. In the mixture of MAO and Cp2ZrMe2, a new unidentified stable complex is observed with an IR band at 822 cm. It is rapidly formed at low Al/Zr ratio and may be a precursor to the active catalyst. A new mechanism is prop...

We report the synthesis and analysis of metallocenes (ferrocene, chromocene, ruthenocene, vanadocene, tungstenocene-dihydride) encapsulated in single wall carbon nanotubes (SWNTs). In the case of ferrocene, efficient filling of the SWNTs was accomplished from both the liquid and the vapor phase. The other two metallocenes were filled from the vapor phase. High resolution transmission electron m...

The syntheses, spectral and structural characterization of metallocenes incorporated normal and expanded calixphyrins are reported.

We report a systematic comparison of the steric properties of different stereoselective olefin polymerization catalysts using the percentage of buried volume, %V(Bur), as a molecular descriptor. For the first time, isoselective and syndioselective group 4 metallocenes are compared with group 4 isoselective phenoxy-amine and group 4 syndioselective phenoxy-imine catalysts using the same molecula...

Key words Catellani reaction - palladium catalysis planar chiral metallocenes remote C–H activation