Directly linked metalloporphyrins: a quest for bio-inspired materials

Abstract

The directly-linked iron–diporphyrin complexes are appealing candidates and fundamental precursors for an extended metalloporphyrin array that can potentially mimic the biological design of energy-harvesting materials. This encouraged us to appraise the layout for the modular fusion of two iron-porphyrin units. Herein, DFT-based calculations suggest that the electronic environment of diporphyrin systems can be tuned according to the topological attachment between the porphyrin units. Subsequently, a gradual increase in the electronic interaction between the constituent porphyrin units triggers a decrease in the HOMO–LUMO gap. This is essential to achieve higher electric conductivity. The spin-polarized electronic transmission is another interesting aspect of these iron–diporphyrin systems and is promising for spintronic applications. The successive theoretical interpretation of the existence of two-dimensional (2D) metalloporphyrin arrays could be the route to design a graphene analog of the covalent metal–organic framework.