Tuning the crystal structures of metal-tetraphenylporphines via a magnetic field

In this work, two new single crystals of copper-tetraphenylporphine (Cu-TPP) (crystals 2 and 3), which were induced by external magnetic fields with strengths of 0.5 and 0.8 T, respectively, have been prepared and characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. Compared with the original Cu-TPP (crystal 1), crystals 2 and 3 exhibit significant differences in their unit cell parameters, crystalline stacking styles and intermolecular interactions, resulting in a "compressed" crystal packing. Here, the number of closer interactions (H center dot center dot center dot H, C center dot center dot center dot H/H center dot center dot center dot C) increased with the magnetic field strength, accompanied by a decrease in the number of pi center dot center dot center dot pi (C center dot center dot center dot C) interactions as a sacrifice. On considering the results of our previous work, the results here suggest that a magnetic field has a different influence on the crystallization process of mono-component and multi-component materials, which will certainly provide some suggestions for the design of crystallization strategies for other materials with the presence of an external magnetic field.