Proton NMR Study of Low‐Spin <i>meso</i>‐Unsubstituted β‐Substituted Alkyl Iron Porphyrins: Remarkable Influence of Peripheral Substitution on Spin Density

Keywords: Porphyrinoids / Out-of-plane distortions / Aromaticity / Frontier molecular orbital theory / Ab initio calculations Porphyrins are noninnocent ligands that facilitate redox processes in many biological reactions. Though the porphyrin dianion is planar and aromatic, in many instances, its skeleton exhibits a variety of out-of-plane (OOP) distortions, which are primarily attributed to steric factors. Nevertheless, these distortions are suspected to play a hidden role in their biochemical reactions, as the nature of the distortion is conserved for a specific functionality across species. The propensity of porphyrins to assist redox reactions remains mysterious, as oxidation and OOP distortions affect their aromaticity. Our quantum chemical modelling of the two-electron oxidation of porphyrin reveals that there are definite electronic reasons behind OOP distortions. An extension of the frontier orbital model of Gouterman to include the occupied b 1g , b 2g and a 1g (σ) molecular orbitals (MOs) is necessary to explain the nature and origin of OOP distortions. The distortions are the effect of the mixing of these σ-type MOs with the π-type a 1u and a 2u highest occupied molecular orbitals (HOMOs). These are further facilitated by the flexibility of the internal [16]annulene skeleton of the porphyrin framework. In the absence of transition metal ions, oxidation usually entails pronounced bond alternation along this internal

show abstract

Electronic Origin of Out‐of‐Plane Distortions in Porphyrins

Pancharatna

Balakrishnarajan

2014

Eur J Inorg Chem

View full text Add to dashboard Cite

show abstract

Dynamics of heme in hemoproteins: proton NMR study of myoglobin reconstituted with iron 3-ethyl-2-methylporphyrin

Juillard

Chevance

Bondon

et al. 2011

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

View full text Add to dashboard Cite

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Proton NMR Study of Low‐Spin meso‐Unsubstituted β‐Substituted Alkyl Iron Porphyrins: Remarkable Influence of Peripheral Substitution on Spin Density

Cited by 2 publications

References 33 publications

Electronic Origin of Out‐of‐Plane Distortions in Porphyrins

Electronic Origin of Out‐of‐Plane Distortions in Porphyrins

Dynamics of heme in hemoproteins: proton NMR study of myoglobin reconstituted with iron 3-ethyl-2-methylporphyrin

Contact Info

Product

Resources

About