The porphyrin center as a regulator for metal–ligand covalency and π hybridization in the entire molecule

Abstract

The porphyrin center is shown to control both the covalency of the central complex and π hybridization with peripheral substituents.

Fundamental electronic changes upon intersystem crossing in large aromatic photosensitizers: free base 5,10,15,20-tetrakis(4-carboxylatophenyl)porphyrin

“…A detailed interpretation of the ground state spectrum is given elsewhere. 32 The first TCPP 4À transient signal that is probed with the temporal resolution of our setup (0.1 ns in Fig. 3b) is expected to probe the lowest singlet excited state (Q x ).…”

“…40,41 The choice of these parameters is based on our past benchmark 32 and the computational efficiency needed for the simulation of multiple core-and valenceexcited states. The geometry optimization was carried out for the S 0 , T 1 , and Q x state without symmetry restrictions to yield more accurate geometries regarding the tilt of the phenyl groups 32 and deformations of the porphyrin macrocycle in the excited states. The given configuration interaction coefficients are the result of ground state TD-DFT calculations.…”

“…This assumption is based on the high similarity in the experimental N K-edge spectra of TCPP and TPP. 32,33 The ORCA package 34 was used for all electronic structure calculations. The aqueous environment of the experimentally investigated molecules was modeled by the conductor-like polarizable continuum model (CPCM).…”

“…35 The B3LYP 36,37 functional was used with the def2-TZVP(-f) 38 basis set, def2/J 39 auxiliary basis set, and Becke-Johnson damping. 40,41 The choice of these parameters is based on our past benchmark 32 and the computational efficiency needed for the simulation of multiple core-and valenceexcited states. The geometry optimization was carried out for the S 0 , T 1 , and Q x state without symmetry restrictions to yield more accurate geometries regarding the tilt of the phenyl groups 32 and deformations of the porphyrin macrocycle in the excited states.…”

Effect of Meso‐Thienyl and Meso‐Furyl Groups on the Electronic Properties of Aromatic 14π Triphyrin(2.1.1)s

“…Thus, triphyrin(2.1.1)s [5,6] have one less pyrrole ring than porphyrins and contain two meso-carbons bridging the two pyrrole rings of three pyrrolic triphyrin macrocycles. [7] Triphyrin(2.1.1)s are monoanionic ligands [8,9] unlike dianionic porphyrins [10,11] and absorb in a relatively low wavelength region than porphyrins. [4] The other small aromatic 14π porphyrinoids are triphyrin(1.1.1)s, which are popularly known as subporphyrins [12,13] and obtained only as B(III) derivatives.…”