Photoresponsive dendron-like metallocomplexes of the crown-containing styryl derivatives of 2,2′-bipyridine
We studied 15-crown-5 ether mono- and bis(styryl) derivatives of 2,2′-bipyridine (1 and 2) as a scaffold to construct photoresponsive complexes possessing metallodendrimer structure. The synthesis and optical properties of one dimensional (1D) Ca2+-containing and octahedral 3D Zn2+-containing complexes with crowned styryl derivatives of 2,2′-bipyridine are described. Bimetallic Ca2+, Zn2+-containing complexes of 1 and 2 possess well-defined structures and particular optical characteristics. The effective size of the complexes was estimated by diffusion-ordered NMR spectroscopy (DOSY) by measuring translation diffusion coefficients. The NMR data on the compositions of the formed complexes are in full agreement with those obtained by an optical method. The properties of the zinc polypyridyl complexes are modified by intermolecular interactions between the crown ether center and the metal ions, so they are potentially useful in the preparation of chemical sensors.