Presselt, Martin and Dehaen, Wim and Maes, Wouter and Klamt, Andreas and Martinez, Todd and Beenken, Wichard J. D. and Kruk, Mikalai (2015) Quantum chemical insights into the dependence of porphyrin basicity on the meso-aryl substituents: thermodynamics, buckling, reaction sites and molecular flexibility. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 17 (21). pp. 14096-14106. ISSN 1463-9076, 1463-9084
Full text not available from this repository. (Request a copy)Abstract
The chemical and sensing properties of porphyrins are frequently tuned via the introduction of peripheral substituents. In the context of the exceptionally fast second protonation step in the case of 5,10,15,20-tetraphenylporphyrin (TPP), as compared to porphin and 5,10,15,20-tetramesitylporphyrin (TMesP), we investigated the macrocycle-substituent interactions of these three porphyrin derivatives in detail. Using quantum chemical thermodynamics calculations, the analysis of geometric structures, torsional profiles, electrostatic potential distributions, and particularly the analysis of molecular flexibilities via ab initio molecular dynamics simulations, we obtained a comprehensive picture of the reactivities of the studied porphyrins and how these are influenced by the meso-substituents. As compared to porphin and TMesP the second protonation of TPP is energetically more favorable and is particularly energetically comparable to its first protonation, instead of being significantly less favorable like in the case of porphyrin and TMesP. Additionally, the second TPP protonation is facilitated by an interplay between out-of-plane (oop) distortion of the protonation site and a pronounced electrostatic binding spot at the protonation site. Furthermore, the second protonation is particularly facilitated in the case of TPP by the large oop-flexibility of the diprotonated species as unraveled by ab initio molecular dynamics simulations.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ZETA VALENCE QUALITY; ACID-BASE EQUILIBRIA; 2-PHOTON ABSORPTION; SOLAR-CELLS; COSMO-RS; CONFORMATIONAL FLEXIBILITY; ELECTRON-DENSITIES; AQUEOUS-SOLUTION; SINGLET OXYGEN; BASIS-SETS; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 31 Jul 2019 08:45 |
| Last Modified: | 31 Jul 2019 08:45 |
| URI: | https://pred.uni-regensburg.de/id/eprint/6247 |
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