A series of supramolecular polymers based on direct coordination of metal ions to the cucurbit[n] urils with the aid of the outer-surface interactions of cucurbit[n] urils could become a new branch in Q s-based coordination chemistry. According to the characteristics of the outer-surface interactions of cucurbit[n] urils, they can be catalogued in: 1) electrodonating effect of the alkyl-substituted groups on the outer-surface of cucurbit[n] urils; 2) interactions between methine or methylene moieties on the outer-surface of cucurbit[n] urils and aromatic moiety of organic structure directing agents; 3) interactions between methine or methylene moieties on the outer-surface of cucurbit[n] urils as well as ion-dipole interactions between positive portal carbonyl carbon of cucurbit[n] urils and chloride anion from polychlorometallate anions; 4) coordination interaction between hydroxyl groups on the outer-surface of cucurbit[n] urils with metal ions. Based on the characteristics of the supramolecular coordination polymers, they have potential applications in the fields, such as absorption, analysis, separation, isolation, and so on.

Contents
1 Introduction
2 Typical outer-surface interactions of cucurbit[n]urils resulting in the formation of Q[n]s-based coordination polymers
2.1 Electrodonating effect of the alkyl-substituted groups on the outer-surface of cucurbit[n]urils
2.2 π…π stacking between portal carbonyl groups of cucurbit[n]uril as well as C—H…π interaction between methine or methylene moieties on the outer-surface of cucurbit[n]urils and aromatic moiety of organic structure directing agents
2.3 Unusual hydrogen bonding between methine or methylene moieties on the outer-surface of cucurbit[n]urils as well as ion-dipole interactions between positive portal carbonyl carbon of cucurbit[n]urils and chloride anion from polychlorometallate anions
2.4 Coordination interaction between hydroxyl groups on the outer-surface of cucurbit[n]urils with metal ions
3 Potential applications of the supramolecular coordination polymers
4 Conclusion and outlook