From Models of Hemoproteins to Self‐Assembled Molecular Wires

Abstract

In nature, the various properties of tetrapyrrolic macrocycles are mostly due to their proteic environment and result from an evolutionary process that is difficult to reproduce during the lifetime of a synthetic chemist. Thus, the task of synthetic chemists attempting to reproduce the biological role of porphyrin architectures, which perform functions from catalysis to light harvesting, is complicated. This account describes how a phenanthroline‐strapped porphyrin architecture initially designed to afford new hemoprotein models led, over the last two decades, to the preparation of highly linear self‐assembled nano‐objects inspired by light‐harvesting architectures. The approach summarized herein mimics, in a very modest way, the polyvalence of tetrapyrrolic macrocycles found in nature.

A water-soluble supramolecular complex that mimics the heme/copper hetero-binuclear site of cytochromecoxidase

“…S4 ‡ ), which was consistent with the spectra of other O 2 complexes of the PFe II /Cu I L n hetero-binuclear systems. 31 – 33 The rR analysis at 77 K (frozen solution of the O 2 adduct) using 405 nm excitation revealed a characteristic band at 578 cm –1 , which shifted to 551 cm –1 under an 18 O 2 atmosphere ( Fig. 5 inset).…”

ORR activity of metalated phenanthroline-strapped porphyrin adsorbed on carbon nanotubes

“…These models employed caps and straps that served to differentiate both faces of tetra-aryl-porphyrin derivatives and to create steric hindrance that mimicked the distal site of the hemoprotein. Over the past years, the properties of a phenanthroline-strapped porphyrin have been exploited in several domains such as the specific recognition of imidazole or the formation of hetero-bimetalic structures containing Fe and Cu for the electrocatalytic reduction of oxygen [42]. In these ditopic ligands, the phenanthroline binds and stabilizes a copper(I) ion at a distance of approximately 4.7 Å from an iron porphyrin, mimicking a heme.…”

Synthesis of Double-Bridged Cofacial Nickel Porphyrin Dimers with 2,2′-Bipyridyl Pillars and Their Restricted Coordination Space

“…The use of porphyrins as molecular building blocks is one of the typical strategies of producing a functionalized nanospace. − On the other hand, 2,2′-bipyridyl is a well-known ligand for transition metal complexes . Various metal complexes having 2,2′-bipyridyl and its derivatives have attracted much attention as photosensitizers and photoredox catalysts. − Combined compounds of porphyrins and 2,2′-bipyridyl or 1,10-phenanthrolinyl derivatives have also been reported, in which multinuclear complexes were prepared. − However, cyclic arrays connected alternately with 2,2′-bipyridyl moieties and porphyrins are limited, except for our cyclic trimer Zn-3 Me (Figure ) connected through 2,2′-bipyridyl moieties and Zn porphyrins . Because the coordination sites on the 2,2′-bipyridyl moieties are directed to the center of the cyclic trimer Zn-3 Me , the compound was applied as a functional ligand for multi-cofacial and multinuclear complexes. − The compound Zn-3 Me -(allylPd) 3 (Figure ), in which three cationic η 3 -allylpalladium species were incorporated as bipyridyl complexes, has been previously reported as a demonstration of the coordination ability of Zn-3 Me …”