Tetravalent Metal Complexes as a New Family of Catalysts for Copolymerization of Epoxides with Carbon Dioxide
摘要:
New tetravalent metal complexes with a trianionic [ONNO]-tetradentate ligand and an ancillary chloride ligand were synthesized as catalysts for the copolymerization of epoxides with carbon dioxide (CO2). All of the titanium, zirconium, germanium, and tin complexes were found to copolymerize epoxides with CO2. In particular, the copolymerization of propylene oxide with CO2 gave the almost-completely alternating copolymers by using titanium or germanium complexes. These results are the first example of the copolymerization using tetravalent metal complexes as a main component of catalysts.
Tetravalent Metal Complexes as a New Family of Catalysts for Copolymerization of Epoxides with Carbon Dioxide
摘要:
New tetravalent metal complexes with a trianionic [ONNO]-tetradentate ligand and an ancillary chloride ligand were synthesized as catalysts for the copolymerization of epoxides with carbon dioxide (CO2). All of the titanium, zirconium, germanium, and tin complexes were found to copolymerize epoxides with CO2. In particular, the copolymerization of propylene oxide with CO2 gave the almost-completely alternating copolymers by using titanium or germanium complexes. These results are the first example of the copolymerization using tetravalent metal complexes as a main component of catalysts.
Ligand-Centered Redox Activity in Cobalt(II) and Nickel(II) Bis(phenolate)-Dipyrrin Complexes
作者:Amélie Kochem、Linus Chiang、Benoit Baptiste、Christian Philouze、Nicolas Leconte、Olivier Jarjayes、Tim Storr、Fabrice Thomas
DOI:10.1002/chem.201202882
日期:2012.11.12
trianionic ligand containing the biologically relevant moieties phenolate and porphyrin was designed and synthesized. One‐electron oxidation of the nickel and cobalt complexes of these ligands affords an unprecedented and highly stable hybrid porphyrinyl–phenoxyl radical bound to the metal center. Two‐electron oxidation of these complexes leads to the M2+–(close‐shell two‐electron oxidized ligand) species