Towards a Definition of Metal Organic NanoTube (MONT)

Metal-Organic Nanotubes (MONT) are a class of one dimension coordination polymers with open channels extended in one direction and assembled in crystalline frameworks with non-covalent interactions. [1] In recent years, some of us have reported the first two isoreticular MONTs assembled by Cu(II) metal atoms, diphosphinate and bipyridine ligands of different length. [2] MONTs are a small subset of Metal Organic Frameworks. On the other side we found several ambiguities and confusions on the nature of MONT in the literature and we decide to give a clear definition of MONT based either on topology and on geometrical constraints. The latter are the smallest dimension of the internal cavity as well as the size of the windows in the lateral walls. With our definition, we extracted 35 "true" MONT from 28000 1D coordination polymers in the CSD database finding that most of the classified MONTs failed to fulfil our geometrical constraint.