Molecular Structures and Energetics of Corrole Isomers: A Comprehensive Local Density Functional Theoretical Study

Abstract

By using geometry optimizations with local density functional theory and double-i plus polarization basis sets, an extensive study has been carried out on the molecular structures and stabilities of free-base and metal-complexed corrole isomers. The optimized structures of normal metallocorroles have been found to agree well with crystallographic results. For both free-base and metal-complexed derivatives, the [I .

Coordination chemistry of corroles with focus on main group elements

“…Based on density functional theory (DFT) calculations, Ghosh and Jynge proposed that gallium(III) may fit perfectly into the coordination core of corroles [36], thus providing the opportunity of obtaining a reference complex for transition metal corroles. This hypothesis was later proved correct indeed by Bendix et al: the metallation of 1 (Fig.…”

Corrole NH Tautomers: Spectral Features and Individual Protonation

“…5 The presence of three NH protons in the corrole macrocyclic core and the inherent asymmetry impose many questions concerning the specific details of the corrole tautomerization mechanism. Quantum chemical calculations predict a substantially lower barrier for corrole tautomerization (2.45 kcal mol −1 ) 6 as compared to that of porphyrins (17 kcal mol −1 ), 7 which leads to a much faster rate of proton migration in the tetrapyrrolic core. The lower symmetry of the Fb corrole macrocycle (C s ) compared to that of a Fb porphyrin (D 2h ) implies that the two tautomeric forms are distinct and structurally quite different (see Scheme 1), which opens the possibility to detect the two NH tautomers for any corrole derivative, independently of the peripheral substitution pattern and even in fluid solutions at room temperature, in contrast to porphyrins where NH tautomers of symmetrically substituted derivatives have been indistinguishable.…”

“…We like to stress here that there is no contradiction between the very close stability of the two corrole NH tautomer ground states (small ΔE S0 ) and the difference in the electronic structure of the two NH tautomers, which is expected to be distinct. 6 Similar stability of the ground states does not necessarily imply a similar electronic structure. The excited states can be influenced much stronger than the ground states (tentatively, the LUMO seems to be more sensitive to the tautomerization state compared to the HOMO).…”

“…6,18 According to the four-orbital model, the absorbance in the visible and near-UV ranges is due to transitions between the two highest occupied (HOMOs) and the two lowest unoccupied molecular orbitals (LUMOs). 19 The Soret band consists of two overlapping bands corresponding to two electronic transitions.…”

A transient form of 2-aza-21-carbaporphyrin prearranged for fusion: DFT studies

“…The density function theory methods have been applied to porphyrin isomers and modified porphyrins [33][34][35][36][37][38][39][40][41]. Previously, apart from synthesis and spectroscopic investigations of sapphyrins and heterosapphyrins we have explored the inverted sapphyrin-planar sapphyrin rearrangement using density functional theory [22,40,41].…”