In some complexes, the arene binds through only two or four carbons, η and η bonding, respectively. In these cases, the arene is no longer planar. Because the arene is dearomatized, the uncoordinated carbon centers display enhanced reactivity. A well studied example is [Ru(η-CMe)(η-CMe)], formed by the reduction of [Ru(η-CMe)]. An example of an [Os(η-CH)(NH))].