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Photo‐Cross‐Linking of Polymethacrylates with Stilbene Chromophores in the Side Chains
Author(s) -
Jahnke Angelika,
Beile Bernhard,
Meier Herbert
Publication year - 2011
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.201100252
Subject(s) - chemistry , polymer , side chain , chromophore , polymerization , photodissociation , irradiation , methacrylate , polymer chemistry , photochemistry , organic chemistry , physics , nuclear physics
Methacrylates (=2‐methylpropenoates) 5 with ( E )‐stilbene (=( E )‐1,2‐diphenylethene) building blocks on tethers of variable length were prepared ( Scheme 2 ) and polymerized ( i.e. , 5 → 6 ; Scheme 3 ) in the presence of AIBN (=2,2′‐azobis(2‐methylpropanenitrile). 4‐[( E )‐2‐Phenylethenyl]phenyl acetate ( 7 ) as model compound established the cyclodimerization as a single irreversible photoreaction. i.e. , ( 7 → 8 – 11 ; Scheme 4 ) in the absence of oxygen. The solution photolysis of the polymers 6 provided a similar result, whereby [2 π +2 π ] cycloadditions of stilbene units of neighboring tethers predominated. On the contrary, the desired photo‐cross‐linking of chaines occurred in the irradiation of polymer films.