Coordination-driven self-assembly of metallodendrimers possessing well-defined and controllable cavities as cores

Abstract

The design and self-assembly of novel cavity-cored metallodendrimers via noncovalent interactions are described. By employing [G0]-[G3] 120 degrees ditopic donor linkers substituted with Fréchet-type dendrons and appropriate rigid di-Pt(II) acceptor subunits, [G0]-[G3]-rhomboidal metallodendrimers and [G0]-[G3]-hexagonal, "snowflake-shaped" metallodendrimers with well-defined shape and size were prepared under mild conditions in high yields. The assemblies were characterized with multinuclear NMR ((1)H and (31)P), mass spectrometry (ESI-MS and ESI-FT-ICR-MS), and elemental analysis. Isotopically resolved mass spectrometry data support the existence of the metallodendrimers with rhomboidal and hexagonal cavities, and NMR data are consistent with the formation of all ensembles. The structures of [G0]- and [G1]-rhomboidal metallodendrimers were unambiguously confirmed via single-crystal X-ray crystallography. The shape and size of two [G3]-hexagonal metallodendrimers were investigated with MM2 force-field modeling.