Search

In the search for more efficient single-center ethene/α-olefin copolymerization catalysts, metallocenes bearing a 2-indenyl substituent pattern have largely been ignored in the past. Here, we show that such a structural motif yields competent linear low-density polyethylene (LLDPE) catalysts. They are also relatively easy to synthesize, allowing for a wide structural amplification. A screening of 28 catalysts reveals that the lead catalyst in this study displays high comonomer affinity and molecular weight capability at industrially relevant temperatures. QSAR models show that steric factors likely contribute stronger than electronic factors to the observed substituent trends, both for comonomer affinity and MW capability.

In the search for more efficient single-center ethene/α-olefin copolymerization catalysts, metallocenes bearing a 2-indenyl substituent pattern have largely been ignored in the past. Here, we show that such a structural motif yields competent linear low-density polyethylene (LLDPE) catalysts. They are also relatively easy to synthesize, allowing for a wide structural amplification. A screening of 28 catalysts reveals that the lead catalyst in this study displays high comonomer affinity and molecular weight capability at industrially relevant temperatures. QSAR models show that steric factors likely contribute stronger than electronic factors to the observed substituent trends, both for comonomer affinity and MW capability.

We report on the synthesis of three perylene-tagged electron donors representing three major types – phthalates, diethers, and alkoxysilanes – which are of importance for the subsequent studies of MgCl2-supported Ziegler–Natta catalysts by means of laser scanning confocal fluorescence microscopy. The obtained products were unambiguously characterized, including by X-ray crystal structure analysis; their photophysical properties (absorption and emission spectra) were investigated as well. Additionally, a reliable and convenient protocol for the multigram synthesis of the required starting material – 3-bromo­perylene (PerBr) – was developed. The key step of this method was synthesis of trialkylsilyl-substituted perylenes, which were further separated by means of flash chromatography followed by conversion of the isolated 3-trialkylsilyl-substituted product to PerBr.

New ansa-zirconocene with bis(inden-2-yloxy)dimethylsilane ligand was synthesized and characterized by NMR spectroscopy and X-ray crystallography. The zirconocene was found to be highly active catalyst of ethylene polymerization and ethylene/hex-1-ene copolymerization upon methylaluminoxane activation.