Crystal engineering of lanthanide–transition-metal coordination polymers

Crystal engineering allows us to predict and control the packing of molecular building units in solid state, which has been attracting much attention due to its exploitation for the synthesis of crystalline materials with novel structures and promising properties. The crystal engineering strategies toward the synthesis of high-nuclearity lanthanide clusters and three-dimensional (3D) lanthanide–transition-metal (Ln–M) coordination polymers were well discussed in the present work. It has shown that the high-nuclearity lanthanide clusters can be rationally synthesized by surface modification strategy. On the basis of the different coordination nature of lanthanide and transition-metal ions, the multifunctional organic ligands with mixed coordination sites such as isonicotinate have been elaborately selected to rationally construct a series of homochrial and achiral 3D Ln–M coordination frameworks built from inorganic heterometallic chains with improved thermal stability. Furthermore, novel 3D Ln–M coordination frameworks have been built from discrete lanthanide clusters (or cluster polymers) and transition-metal clusters (or cluster polymers) by faultlessly harmonizing the subtle relationship between these two different types of metal cluster or cluster polymer units. The current work offers us great potential toward the pursuit of rational synthesis of Ln–M coordination assemblies on the basis of crystal engineering principles.