Solution Studies and Crystal Structures of Heteropolynuclear Potassium/Copper Complexes with Phytate and Aromatic Polyamines: Self-Assembly through Coordinative and Supramolecular Interactions

Phytate (L12−) is a relevant natural product. It interacts strongly with biologically relevant cations, due to the high negative charge exhibited in a wide pH range. The synthesis and crystal structures of the mixed‐ligand Cu(II) polynuclear complexes K(H2tptz)0.5[Cu(H8L)(tptz)] ⋅ 3.6H2O (1), K(H2O)3{[Cu(H2O)(bpca)]3(H8L)} ⋅ 1.75H2O (2), and K1.5(H2O)2[Cu(bpca)](H9.5L) ⋅ 8H2O (3) (tptz=2,4,6‐tri(pyridin‐2‐yl)‐1,3,5‐triazine; Hbpca=bis(2‐pyridylcarbonyl) amine) are reported herein. They were obtained by the use of an aromatic rigid amine, which satisfies some of the metal coordination sites and promotes the hierarchical assembly of 2D polymeric structures. Speciation of phytate−Cu(II)−Hbpca system and determination of complex stability constants were performed by means of potentiometric titrations, in 0.15 M NMe4Cl at 37.0 °C.