Spherical Particles by Metal-Organic Coordination

Significance

The spherical micro- and nanoparticles composed of polymerized metal-ligand networks were prepared by the coordination chemistry induced assembly of metal ions and homochiral carboxylate-functionalized binaphthyl bis-metallo-tridentated Schiff base (BMSB) building blocks. For example, Zn-BMSB-Zn (3a) formed within one hour upon slow diffusion of diethylether into a solution containing Zn(OAc)₂ (1a) and Zn-BMSB (2a) in a 1:1 ratio at room temperature. The addition of diethylether or pentane to the solution results in precipitation of spherical particles with diameters of 1.60 ± 0.47 µm (Et₂O) or about 5 µm (pentane). The authors observed initial formation of particles with diameters of a few hundred nanometers, which coalesce and anneal into uniform and smooth microparticles. Spherical particles of Cu-BMSM-Cu (3b) and Ni-BMSM-Ni (3c) were also prepared via an analogous procedure.