Structural Aspects of Porphyrins for Functional Materials Applications

Abstract

Porphyrinic compounds comprise a diverse group of materials which have in common the presence of one or more cyclic tetrapyrroles known as porphyrins in their molecular structures. The resulting aromaticity gives rise to the semiconducting properties that make these compounds of interest for a broad range of applications, including artificial photosynthesis, catalysis, molecular electronics, sensors, non-linear optics, and solar cells. In this brief review, the crystallographic attributes of porphyrins are emphasized. Examples are given showing how the structural orientations of the porphyrin macrocycle, and the inter-porphyrin covalent bonding present in multiporphyrins influence the semiconducting properties. Beginning with porphine, the simplest porphyrin, we discuss how the more complex structures that have been reported are described by adding peripheral substituents and internal metalation to the macrocycles. We illustrate how the conjugation of the π-bonding, and the presence of electron donor/acceptor pairs, which are the basis for the semiconducting properties, are affected by the crystallographic topology.

Nonlinear Optical Switching in Regioregular Porphyrin Covalent Organic Frameworks

“…Figure 3presents the open aperture Z-scan curves for a) Por-COF-HH, b) Por-COF-ZnCu, and c) Por-COF-ZnNi at the peak intensities of 0.01 and 0.25 GW cm À2 .N otably,a tt he lower intensity of 0.01 GW cm À2 all Por-COFs show SA behavior. [14,15] The b value increases in the following order:Por-COF-ZnCu > Por-COF-ZnNi > Por-COF-HH. This RSA-SA-RSA switching behavior is attributed to the dominant excited-state absorption at lower intensities (far from focus) and saturation of excited states at higher intensity (near the focus).…”

Synthesis of μ2‐Oxo‐Bridged Iron(III) Tetraphenylporphyrin–Spacer–Nitroxide Dimers and their Structural and Dynamics Characterization by using EPR and MD Simulations

“…Porphyrins are heterocyclic organic compounds that display a large variability of molecular structures and physicochemical properties . The variability of porphyrin structures is achieved in several different ways, for instance, by metalation of the macrocycle core, alteration of peripheral substituents, or linkage of multiple macrocycles together.…”

“…Porphyrins are heterocyclic organic compoundst hat display a large variability of molecular structures and physicochemical properties. [1,2] The variability of porphyrin structures is achieved in several different ways, for instance, by metalation of the macrocycle core, alteration of peripheral substituents, or linkage of multiple macrocyclest ogether.T his provides al arge playgroundf or designing new materials with desired properties and, hence,c auses tremendous interest for porphyrins in differentf ields of natural sciences and chemical engineering. [2] The most common porphyrins include tetraphenylporphyrin (TPP) and octaethylporphyrin (OEP).…”

Crystallography of Functional Materials

“…The paper by McGuire [7] presented an overview of the crystal structures metal di-and tri-halides, calling attention to the triangular and honeycomb transition metal cation nets and stacking sequences, along with their magnetic structures and properties. The paper by Cook et al [9] presented an overview of the crystallographic attributes of porphyrins with examples illustrating how the structural orientations of the porphyrin macrocycle and the inter-porphyrin covalent bonding present in multiporphyrins can influence the semiconducting properties.…”

“…Cook et al [9] reviewed the structure of the parent porphyrin compounds, the peripheral substituents, the metalation of the macrocycle core, the role of covalent inter-molecular bonding, and the electronic properties as related to structure. Various factors, important in optimizing porphyrin semiconducting properties, were summarized and discussed at the molecular level, and in single crystals, thin films, and bulk polycrystalline materials.…”