Hansen, Helge-Boj published the artcileThe Stronger the Better: Donor Substituents Push Catalytic Activity of Molecular Chromium Olefin Polymerization Catalysts, Category: pyridine-derivatives, the main research area is donor substituents chromium; chromium, ligand effects, olefin polymerization, supported catalysts, UHMW-PE.
The donor strength of bifunctional pyridine-cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para-position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor strength and the nitrogen-chromium distance as well as the electronic absorption maximum is exptl. observed The connection of electron-donating groups in the ligand backbone leads to an efficient transfer of the electronic influences to the catalytically active metal center without restricting it through steric effects. Therefore, catalytic olefin polymerization activity, which is already very high for the previously studied catalysts, increase considerably by attaching para-amino groups to the chelating pyridine or quinoline, resp. Combining electron-rich indenyl ligands with para-amino substituted pyridines lead to the highest catalytic activities observed so far for this class of organo chromium olefin polymerization catalysts. The resulting polymers are of ultra-high mol. weight and the ability of the catalysts to incorporate co-monomers is also very high.
Chemistry – A European Journal published new progress about Crystal structure. 24484-93-3 belongs to class pyridine-derivatives, name is Methyl 4-chloropicolinate, and the molecular formula is C7H6ClNO2, Category: pyridine-derivatives.