文摘
A molecular pentafoil knot and doubly and triply entwined [2]catenanes based on circular Fe(II) double helicate scaffolds bind halide anions in their central cavities through electrostatic and CH路路路X鈥?/sup> hydrogen-bonding interactions. The binding is up to (3.6 卤 0.2) 脳 1010 M鈥? in acetonitrile (for pentafoil knot [2路Cl](PF6)9), making these topologically complex host molecules some of the strongest synthetic noncovalent binders of halide anions measured to date, comparable in chloride ion affinity to silver salts.