Monitoring the crystal growth and interconversion of new coordination networks in the self-assembly of MCl2 salts (M = Co, Ni, Cu, Cd) and 1,3-bis(4-pyridyl)propane

The combined use of microscopy methods and conventional X-ray crystallography offers new possibilities for the study of the self-assembly of coordination networks. This approach has been applied to the reactions Of MCl2 salts (M = Co, Ni, Cu, Cd) and 1,3-bis(4-pyridyl)propane (bpp). Copper gives [Cu(bpp)(3)Cl-2].2H(2)O (1), [Cu(bpp)(2)Cl]Cl.1.5H(2)O (2), and [Cu(bpp)(2)Cl-2].2.75H(2)O (3), that are 1D, 2D, and 3D polymers, respectively. Monitoring of the crystal growth shows that 1 and 2 are formed from the same mixtures in water, but at different times and conditions and can be interconverted (figure). Both 1 and 2 are transformed into 3 when suspended in EtOH.