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Entropy‐Driven Selectivity for Chain Scission: Where Macromolecules Cleave
Author(s) -
Pahnke Kai,
Brandt Josef,
Gryn'ova Ganna,
Lin Ching Y.,
Altintas Ozcan,
Schmidt Friedrich G.,
Lederer Albena,
Coote Michelle L.,
BarnerKowollik Christopher
Publication year - 2016
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.201508531
Subject(s) - macromolecule , cleave , covalent bond , chemistry , bond cleavage , supramolecular chemistry , polymer , adduct , selectivity , cleavage (geology) , dynamic covalent chemistry , dissociation (chemistry) , molecule , computational chemistry , polymer chemistry , organic chemistry , materials science , catalysis , biochemistry , fracture (geology) , composite material , enzyme
We show that, all other conditions being equal, bond cleavage in the middle of molecules is entropically much more favored than bond cleavage at the end. Multiple experimental and theoretical approaches have been used to study the selectivity for bond cleavage or dissociation in the middle versus the end of both covalent and supramolecular adducts and the extensive implications for other fields of chemistry including, e.g., chain transfer, polymer degradation, and control agent addition are discussed. The observed effects, which are a consequence of the underlying entropic factors, were predicted on the basis of simple theoretical models and demonstrated via high‐temperature (HT) NMR spectroscopy of self‐assembled supramolecular diblock systems as well as temperature‐dependent size‐exclusion chromatography (TD SEC) of covalently bonded Diels–Alder step‐growth polymers.