A [2]catenane and a [2]rotaxane as prototypes of topological and euclideanmolecular "Rubber gloves"

A [2]catenane and a [2]rotaxane have been prepared from a C-2-symmetric, 2, 9-diphenyl-1,10-phenanthroline-based (dpp-based) macrocycle incorporating a 1,5-dioxynaphthatene subunit by means of the transition metal templated te chnique. In the case of the catenane, this macrocycle is interlocked with a dpp-based macrocycle that is oriented through the location of a p-tolyl su bstituent in the 4-position of the phenanthroline subunit. In the case of t he rotaxane, the C-2-symmetric macrocycle is threaded onto an oriented. dum bbell-shaped molecule, based on the same 4-p-tolyt-1,10-phenanthroline subu nit, which bears tetraarylmethane stoppers. Both species are chemically ach iral molecules, yet they are composed entirely of asymmetric, mirror-image conformations. Conformational enantiomerization processes therefore take pl ace exclusively by chiral pathways, conferring on these molecules the "rubb er glove" property. However, while the molecular graph (constitutional form ula) of the [2]rotaxane can be deformed into a planar and, hence, rigidly a chiral representation, a feature shared by a few other compounds in the lit erature that have been characterized as "Euclidean rubber gloves", the mole cular graph of the [2]catenane cannot be deformed in this way. It therefore has the unique property of being a chemically achiral "topological rubber glove".