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Optically active polymers bearing side‐chain photochromic moieties: synthesis and chiroptical properties of methacrylic homopolymers with pendant trans ‐azobenzene chromophores bound through L ‐leucine, L ‐valine and L ‐proline amino acid spacers
Author(s) -
Carlini Carlo,
Fissi Adriano,
Raspolli Galletti Anna Maria,
Sbrana Glauco
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20000801)201:13<1540::aid-macp1540>3.0.co;2-8
Subject(s) - azobenzene , side chain , chemistry , polymer chemistry , monomer , circular dichroism , macromolecule , hydrogen bond , polymer , methacrylic acid , chromophore , photochromism , photochemistry , stereochemistry , molecule , organic chemistry , biochemistry
Novel optically active monomers, based on different L ‐amino acid residues such as trans ‐( S )‐4‐(2‐methacryloylamino‐3‐methylbutanoylamino)azobenzene, trans ‐( S )‐4‐(2‐methacryloylamino‐4‐methylpentanoylamino)azobenzene and trans ‐( S )‐4‐( N ‐methacryloyl‐2‐pyrrolidinoylamino)azobenzene, have been prepared and homopolymerized by free radical initiation. Circular dichroism spectra of the resulting polymers, as compared with those of the corresponding low molecular weight analogues, purposely synthesized, allow one to suggest that the macromolecules assume in solution achiral or chiral conformations with a prevailing screw sense, depending on the bulkiness and rigidity of the L ‐amino acid residue present in the side chains. The role of intra‐ and/or inter‐molecular hydrogen bonding between side‐chain amido groups along the backbone and the structural requirements of the chiral groups in determining the macromolecular arrangement is also discussed.