On the planarity and resonance effect of tetraphenylporphyren and its metallocomplexes

Solvent Tuning of the Optical Absorption and Fluorescence Properties of Meso-tetra(aryl)porphyrins and Their Dications With Weak and Strong Carboxylic Acids

“…The anisole group seems to have a weaker electron donating strength in these solvents that may be due to the different dihedral angles between the aryl substituents and porphyrin mean plane of the porphyrins. It is noteworthy that the dihedral angle of meso substituents is significantly smaller in solution than the solid state [6c] so that dihedral angels of 60-85 8 in solid state and 40 8 in solution were calculated by Wolberg for TPP [24] . Furthermore, the presence of -OCH 3 groups at the para position of H 2 T(4-OMe) PP enables it to form hydrogen bonds with CH 3 OH and therefore a decrease in electron donor ability to porphyrin core is expected.…”

Electrochemical reduction of l-(meso-tetraphenylporphyrin)-pyridinium cations

“…When the porphyrin ligand contains a metal, the dorbitals of the latter interact with p-orbitals of the porphyrin ring (d-p interactions) [20,[33][34][35] resulting in a distribution of p electrons that differs from the situation on the free-base porphyrin. Because of their perpendicular configurations or steric hinderance [36][37][38], the aromatic substituents of the porphyrin ring do not allow any p interactions with the metalloporphyrin. Thus, the interactions between the metalloporphyrin and the pyridinium cation in our systems would occur through inductive action.…”

Estimation of specific interaction between several Co porphyrins and carbon black: its influence on the electrocatalytic O2 reduction by the porphyrins

“…However, in solution, rotation of the phenyl groups would easily occur [28]. Using Lennard-Jones potentials and resonance energies, it has been calculated in tetraphenylporphyrin that the energy configuration is lowest when the angle between the phenyl rings and the porphyrin ring is 44° [29]. For CoTMP and CoTF 5 PP, the methyl and fluoro groups at the ortho position prevent rotation of the phenyl rings at the meso position due to the strong repulsion by the pyrrole hydrogens [28].…”