Hydroxy-Functionalized Bipyridine and Tris(bipyridine)metal Chromophores: Synthesis and Optical Properties
Résumé
A new family of symmetrically and unsymmetrically-substituted 4,4′-bis[(dialkylamino)styryl]-2,2′-bipyridine ligands, containing 1−4 hydroxy groups on their dialkylamino moieties, have been synthesized. They are readily prepared in good to excellent yields from 4,4′-dimethyl-2,2′-bipyridine and tetrahydropyranyloxy-protected [(hydroxyalkyl)amino]benzaldehydes. These chromophores display excellent thermal stabilities, with decomposition temperatures of up to 310 °C. The influence of the OH groups on the optical properties (absorption and emission) is discussed. The synthesis of the corresponding heteroleptic and homoleptic tris(bipyridine)metal(II) complexes (M2+ = Ru2+, Zn2+), as building blocks for the elaboration of macromolecular NLO-phores, is also described.