Effect of transition metal cations on assembly of highly ordered 2D multiporphyrin arrays on liquid and solid substrates

Abstract

Metal-ligand supramolecular coordination at the air/water interface offers a route to generate highly ordered 2D multichromophore architectures for fabricating film-like surface attached metal organic frameworks (SURMOF) for applications in electronics, photonics and chemical sensing. Metal complexes of tetrapyridyl porphyrins (TPyP) are well known as convenient building blocks for the assembly of 3D coordination polymers. Herein, we suggest a new strategy of the assembly of highly ordered 2D coordination networks in Langmuir monolayers by using non-metalated ligands as starting tectones, instead of the metal complexes of tetrapyridyl porphyrin. High degree of structural ordering of 2D multiporphyrin arrays with face-on orientation of macrocycles is achieved by the interaction of metal ions with peripheral groups of the ligand as well as with macrocyclic core. A combination of thermodynamic analysis with spectral studies was applied to determination of both types of complex formation in the monolayer. Structural order in 2D hybrid networks depends on the type of initiating metal ion and it increases in a row Cd(II) < Cu(II)