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Non‐Innocent Methylene Linker in Bridged Lewis Pair Initiators
Author(s) -
Weger Michael,
Grötsch Raphael K.,
Knaus Maximilian G.,
Giuman Marco M.,
Mayer David C.,
Altmann Philipp J.,
Mossou Estelle,
Dittrich Birger,
Pöthig Alexander,
Rieger Bernhard
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201902833
Subject(s) - linker , methylene , lewis acids and bases , chemistry , polymer chemistry , medicinal chemistry , computer science , organic chemistry , catalysis , programming language
Deprotonation usually occurs as an unwanted side reaction in the Lewis pair polymerization of Michael acceptors, for which the conjugated addition of the Lewis base to the acid‐activated monomer is the commonly accepted initiation mechanism. This has also been reported for B−P‐based bridged Lewis pairs (BLPs) that form macrocyclic addition products. We now show that the formerly unwanted deprotonation is the likely initiation pathway in the case of Al−P‐based BLPs. In a detailed study of a series of Al−P‐based BLPs, using a combination of single‐crystal diffraction experiments (X‐ray and neutron) and mechanistic investigations (experimental and computational), an active role of the methylene bridge was revealed, acting as a base towards the α‐acidic monomers. Additionally, the polymerization studies proved a living behavior combined with significantly high activities, narrow molecular mass distributions, and the possibility of copolymerization.