Chiral donor-π-acceptor azobenzene dyes

Abstract Four chiral donor–π-acceptor azobenzene dye conjugates were synthesized and characterized. Chiral moieties, namely ( S )-(+)-2-(6-methoxy-2-naphthyl)propionic acid (naproxen) and ( S )-2-aminopropionic acid ( l -alanine), were attached to either the donor end or the acceptor site of the azo compound using ester or amide bonds, respectively. The structures of the molecules were verified using 1 H NMR, 13 C NMR and ESI TOF mass spectrometry; spectral properties were evaluated with UV–vis and CD spectrometry whilst thermal stability was determined by TGA. The compounds displayed a broad absorption maximum in the visible region between 433 and 483 nm. All compounds showed relatively high thermal stability, decomposition temperatures being ∼200 °C.