Effect of composition on the properties of novel optically active methacrylic copolymers containing side-chain zinc–porphyrin chromophores suitable to chiral recognition

New chiral methacrylic copolymers, bearing in the side chain one or two l-lactic acid residues linked to a porphyrin moiety, with variable molar content of methyl methacrylate co-units, have been prepared by radical copolymerization of the corresponding monomers. The resulting macromolecules have been fully characterized both in solution and in the solid state with particular attention to their thermal, UV–Vis and chiroptical properties by comparison with those of the related porphyrin containing homopolymers and monomeric models. The zinc–porphyrin coordination complexes of the above functional derivatives have been studied as macromolecular hosts for the chiral recognition of optically active diamine on the basis of the amine/zinc coordination complex exhibiting circular dichroism spectra related to the absolute configuration of the diamine guest. The results are discussed in terms of diamine complexation ability by the zinc–porphyrin complex which is related to copolymer composition and, consequently, to backbone flexibility and chromophore mobility.