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Main‐Chain Scission of a Charged Fifth‐Generation Dendronized Polymer
Author(s) -
Yu Hao,
Schlüter A. Dieter,
Zhang Baozhong
Publication year - 2012
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.201200478
Subject(s) - chemistry , monomer , trifluoroacetic acid , bond cleavage , polymer , polymer chemistry , polyelectrolyte , polymerization , mass spectrometry , degree of polymerization , organic chemistry , chromatography , catalysis
During divergent synthesis of the next higher‐generation dendronized polymer (DP), the fifth‐generation DP, PG5, with a number‐average degree of polymerization, ( i.e. , number of monomeric units) P n , of ca. 500 underwent main‐chain scission. This happened in the step when its peripheral Boc groups were removed by the treatment with trifluoroacetic acid (TFA), and thus a heavily charged polyelectrolyte formed as an intermediate. Atomic Force Mircoscopy (AFM) analysis of the product after drop‐casting onto mica showed a large majority of short deprotected PG5 chains with P n of ca. 40, as well as some smaller features that by MALDI‐TOF mass spectrometry and 1 H‐NMR spectroscopy were assigned to the hypothetical monomer, deprotected MG5. This behavior is compared to a recently reported main‐chain scission of a closely related PG5 which, however, resulted in significantly longer fragments. While this difference cannot yet be fully explained, questions are formulated which will guide future research.