Supramolecular gels have evolved into a class of smart/functional nanomaterials with extensive application potentials recently. Most supramolecular gels studied today employ hydrogen bonding or molecular stacking as the driving force for gelation. Despite the major role that metal coordination plays in supramolecular chemistry, the use of metal-ligand interactions in the area of supramolecular gels has been somewhat neglected until very recently. Supramolecular gels including metal ions can capitalize on the unique richness of the attributes of metal ions such as photo-electronic, catalytic, redox, which stimulates research in this area. In this review, the basic concepts of metallogels are first given, and then detailed examples are presented to relate the molecular structures especially the complexing groups, metal ions used to the properties and functions of the gels, which are divided into two categories: gelator based metallogels and coordination polymer gels. Moreover, abnormal gelation behaviors in metallogels will be briefed.

Contents
1 Definition of supramolecular metallogel
2 Classification of supramolecular metallogels
2.1 Metallogels based on gelators
2.2 Metallogels based on coordination polymers
3 Abnormal gelation behaviors of metallogels
4 Conclusions