Self-Assembly of Interlocked Structures and Open Framework Materials using Coordination Bonds

Abstract

Syntheses of molecular necklaces and open framework materials using coordiantion bonds are described. In the synthesis of molecular necklaces, the barrel-shape molecule cucurbituril is used as a molecular “bead” and metal ions or metal complexes are used as “glue” or “angle connectors”. Two different approaches were taken. In one approach, linear pseudorotaxanes react with Pt(en)(NO₃)₂ (en = ethylenediamine) to produce [4]MNs and [5]MNs. In the other approach, a′ 2 + 2′ approach, preorganized, L-shaped pseudorotaxanes containing two molecular “beads” react with a metal ion (or a metal complex with cis vacant coordination sites) to form [5]MNs. Rubidium and cucurbituril form a one-dimensional coordination polymer in the solid state, in which cucurbituril molecules stack atop one another through coordination of their carbonyl groups to the rubidium ions in between. The coordination polymer chains are arranged in such a way as to produce a honeycomb structure with large linear hexagonal channels parallel to the polymer chains.

Key Words:

• self assembly
• interlocked structures
• open framework materials
• metal ions
• supramolecular chemistry