The porphyrin center as a regulator for metal–ligand covalency and π hybridization in the entire molecule. Issue 43 (29th October 2021)

• Record Type: Journal Article
• Authors: Büchner, Robby; Fondell, Mattis; Haverkamp, Robert; Pietzsch, Annette; Vaz da Cruz, Vinícius; Föhlisch, Alexander
• Is Part Of: Physical chemistry chemical physics. Volume 23:Issue 43(2021)
• Page Start: 24765
• Page End: 24772
• Publication Date: 2021-10-29
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d1cp03944j
• Languages: English
• ISSNs: 1463-9076

Abstract

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