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Zinc Complexes with Guanidine–Pyridine Hybrid Ligands – Guanidine Effect and Catalytic Activity
Author(s) -
Börner Janna,
dos Santos Vieira Ines,
Jones Matthew D.,
Döring Artjom,
Kuckling Dirk,
Flörke Ulrich,
HerresPawlis Sonja
Publication year - 2011
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201100540
Subject(s) - guanidine , chemistry , zinc , pyridine , catalysis , polymerization , ligand (biochemistry) , polymer chemistry , solvent , monomer , combinatorial chemistry , organic chemistry , medicinal chemistry , polymer , biochemistry , receptor
Abstract Two new series of guanidine–pyridine ligands have been synthesised by the reaction of various chloroformamidinium chlorides with 8‐aminoquinoline or 2‐picolylamine. The ligands were treated with either zinc chloride or zinc acetate to prepare the corresponding complexes, which were tested as initiators in the solvent‐free ring‐opening polymerisation of d,l ‐lactide. The effect of the guanidine ligand on the catalytic activity of the zinc complexes was investigated. A great number of the synthesised complexes showed appreciable polymerisation activity. 13 new zinc guanidine complexes have been structurally characterised, including the first examples of structures comprising a tetraethylguanidine unit. The experimental results were complemented by a density functional study, which has probed the influence of substituents at the guanidine unit. Especially for the tetraethylguanidine systems, insights into the strength of delocalisation within guanidine moieties are provided.