Meso-Helicates with Rigid Angular Tetradentate Ligand: Design, Molecular Structures, and Progress Towards Self-Assembly of Metal鈥揙rganic Nanotubes
文摘
The self-assembly of two novel metallosupramolecular complexes of the general formulas [L2M2(CH3CN)4][BF4]4 (M = Co, 1a; M = Ni, 1b), where L stands for the tetradentate ligand 3,5-bis[4-(2,2鈥?dipyridylamino)phenylacetylenyl]toluene, is reported together with their molecular structures ascertained by single-crystal X-ray diffraction studies. Complexes 1a and 1b are isostructural and show the formation of dinuclear meso-helicates with the two octahedral metal centers displaying respectively 螖 and 螞 configurations. These meso-helicates display large nanocavities with metal---metal separation distance of >2 nm; furthermore, 蟺鈥撓€-stacking occurs among individual units to form one-dimensional (1D) polymers which further autoassemble in another direction through 蟺鈥撓€ contacts among neighboring chains to generate a two-dimensional (2D) network with regular nanocavities. Our approach might be of interest to prepare metal鈥搊rganic nanotubes via a bottom-up strategy depending on the assembling functional ligand and the geometry of molecular building block.