The influence of metal cations on the formation of phthalocyanine/porphyrin heterodimers and nanoporous cocrystals

Porphyrin-containing Phthalocyanine Nanoporous Crystals (PNCs) have been prepared previously by the cocrystallisation of octa(2[Formula: see text],6[Formula: see text]-di-iso-propyphenoxy)phthalocyanine [(dipPhO) 8 Pc] and its metalated derivatives with metal-free tetraphenylporphyrin (TPP). Here we report the effect of the central cations (M [Formula: see text] H 2 , Co, Cu, Zn) on heterodimer formation, both in solution and in cocrystallisations, for all sixteen possible combinations of (dipPhO) 8 PcM with TPPM. UV/visible spectroscopy shows a clear trend of Cu[Formula: see text] > 2H[Formula: see text] > Co[Formula: see text] > Zn[Formula: see text] for encouraging or discouraging heterodimer formation, which can be rationalised by the propensity of the metal cation to bind to axial ligands when incorporated into porphyrin or phthalocyanine macrocycles. Attempted cocrystallisations of all 16 (dipPhO) 8 PcM/TPPM combinations yielded 13 heterodimer-based PNCs, with only (dipPhO) 8 PcZn failing to provide a cocrystal with TPPM (Co, Cu, Zn). This study further demonstrates the remarkable efficiency of (dipPhO) 8 PcM in directing the structure of PNC cocrystallisations. It suggests a simple method for placing two metal cations of choice within van der Waals distance of one another within a well-defined, predictable crystal structure.