Dicyanometallates as Model Extended Frameworks

We report the structures
of eight new dicyanometallate frameworks containing molecular extra-framework
cations. These systems include a number of hybrid inorganic–organic
analogues of conventional ceramics, such as Ruddlesden–Popper
phases and perovskites. The structure types adopted are rationalized
in the broader context of all known dicyanometallate framework structures.
We show that the structural diversity of this family can be understood
in terms of (i) the charge and coordination preferences of the particular
metal cation acting as framework node, and (ii) the size, shape, and
extent of incorporation of extra-framework cations. In this way, we
suggest that dicyanometallates form a particularly attractive model
family of extended frameworks in which to explore the interplay between
molecular degrees of freedom, framework topology, and supramolecular
interactions.