Supramolecular stacks of bis(imidazolyl)porphyrin through metal coordination

cis- and trans-bis(1-methyl-2-imidazolyl)tetraethyltetramethylprophyrin Mg complexes were prepared. H-1 NMR, absorption, and fluorescence spectra suggest that Mg has a high tendency toward dimer formation through coordination from imidazolyl to metal in a similar way to Zn, and accepts further the sixth coordination, which never occurred in Zn complexes. Propagation of the organization from a dimer to a trimer for trans-Mg complex starts at such a low concentration level as 10(-5) M (1 M=1 mol dm(-3)) and a 2x10(-3) M solution organized the system to a 2.34 mer on average.