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

Abstract

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 MCl 2 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.

Peculiar phenomena of structural transformations triggered from a nickel coordination polymer

“…Fortunately, green block-shaped crystals were afforded faultlessly through methanol mediation, and were chemically and structurally identical with the crystals of 2, as evidenced using single-crystal diffraction and PXRD (Fig. 26 Solid-state SCSC structural transformations CP 1 contains two coordinated water molecules in the asymmetric unit. The methanol-mediated conversion from 1 to 2 was gradually completed over time.…”

Multi-scale crystal engineering of metal organic frameworks

“…During the course of the reaction, the fast growing facets are fated to disappear quickly, while those having slower growth rates will eventually determine the final crystal habit, as depicted in the morphodrome illustrated in Figure 12, showing the changes of crystal habits of [Cu(BPP) 2 Cl 2 ] n ·2.75nH 2 O crystals with 1,3-bis(4-pyridyl)propane (BPP) ligand and Cu 2+ concentrations [86]. It is worth emphasizing that morphological evolution induced by changes of saturation levels during crystal growth is determined by the synthesis time.…”

Phase Stability and Morphology of Gel Grown Crystals: The Case of CdCl2-bpp Polymeric System

“…Here, we exploit gels as a tool to go a step further with respect to the static control of concentrations. We extend the experimental study of CdCl2:bpp (bpp = 1,3-bis(4-pyridyl)propane, Scheme 1) CP system [25,26] by performing a phenomenological comparative analysis of the crystallization behaviour in both solution and gel substrate in response to a systematic variation of the crystallization conditions, including the growth technique and the experimental set-up. We aim at clarifying the role of key physicochemical variables in determining the chemical nature and the morphology of the final crystallization products.…”