Metallophilicity versus π-π Interactions: Argentophilicity in Porphyrin Dimer

The interaction between two unsupported Ag(III)porphyrins, which exist as a metalloporphyrin dimer has been studied. The UV-visible spectrum shows only slight change in Soret band position indicative of Ag(III) formation. Optimized structure of the complexes has clearly revealed that only metal-centered oxidation results in short Ag-N (porphyrin) distance with large distortion in the porphyrin macrocycle. The dispersion effect brings two rings more closer to form an unprecedented Ag(III)···Ag(III) interaction and cancel out the π-π repulsion. The interaction energy was found to be 55.34 Kcal/mol and was further supported by electron localization function, AIM analysis. The Ag(III) dimer also gives pink emission at low temperature. This type of interaction can be exploited to design several light responsive materials and molecular semiconductors.