TY  - JOUR
A1  - Büchner, Robby
A1  - Fondell, Mattis
A1  - Haverkamp, Robert
A1  - Pietzsch, Annette
A1  - Vaz da Cruz, Vinícius
A1  - Föhlisch, Alexander
T1  - The porphyrin center as a regulator for metal-ligand covalency and pi hybridization in the entire molecule
T2  - Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies
N2  - The central moiety of porphyrins is shown to control the charge state of the inner complex and links it by covalent interaction to the peripheral substituents. This link, which enables the versatile functions of porphyrins, is not picked up in the established, reduced four orbital picture [Gouterman, J. Mol. Spectrosc., 1961, 6, 138]. X-ray absorption spectroscopy at the N K-edge with density functional theory approaches gives access to the full electronic structure, in particular the pi* manifold beyond the Gouterman orbitals. Systematic variation of the central moiety highlights two linked, governing trends: The ionicity of the porphyrin center increases from the aminic N-H to N-Cu to N-Zn to N-Mg to the iminic N:. At the same time covalency with peripheral substituents increases and compensates the buildup of high charge density at the coordinated nitrogen sites.
Y1  - 2021
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/61169
SN  - 1463-9076
SN  - 1463-9084
VL  - 23
IS  - 43
SP  - 24765
EP  - 24772
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -