Crystallization Behavior of Coordination Polymers. 1. Kinetic and Thermodynamic Features of 1,3-Bis(4-pyridyl)propane/MCl₂ Systems

A series of one-, two-, and three-dimensional (1D, 2D, and 3D) coordination polymers has been crystallized from solution as well as in gelled media, by controlled reaction of the flexible ligand 1,3-bis(4-pyridyl)propane with MCl2 salts (M = Mn, Fe, Co, Ni, Cu, Cd, Zn). Attention was paid to the role of kinetic and thermodynamic control upon selection of the final products that can be obtained with different optimized crystallization techniques. It is shown that the correct use of crystallization techniques allows tuning of the metal to ligand ratio and absolute concentrations and, hence, control of the crystallization of metal−organic frameworks, including their solvent-mediated phase transitions.