Issue 32, 2023

Histamine-bound magnesium porphyrins: diverse coordination modes, inhibitory role in photodegradation of chlorophyll a and antioxidant activity

Abstract

The neurotransmitter histamine exists in two isomeric forms and could be an interesting ligand due to three nitrogen atoms with the possibility of binding to metals in different ways besides its crucial role in biological systems. However, no metal–histamine interaction is known in the literature. Therefore, two histamine-bound magnesium porphyrins [MgT(4-Cl)PP(hist)2] 1 and [MgT(4-Br)PP(hist)] 2 have been synthesized and structurally characterized. Interestingly, 1 is a hexa-coordinated magnesium porphyrin due to the axial coordination of two histamine molecules via the nitrogen of the aliphatic amino group with the Mg–Nhistamine distance of 2.300 Å, while 2 is penta-coordinated due to the axial coordination of one histamine molecule through the imidazole nitrogen atom with the Mg–Nhistamine distance of 2.145 Å. The diverse coordination modes of this unique ligand are explored for the first time. Theoretical studies at the level of DFT supported the binding of histamine via imidazole nitrogen atoms for complex 2. Histamine-bound magnesium porphyrins are found to be stable against the photodegradation of magnesium porphyrin in the presence of light and oxygen. Freshly isolated chlorophyll a from spinach showed similar resistivity against photodegradation. Moreover, the histamine-bound complexes showed higher antioxidant activity for 1 (92.45%) compared to the free base porphyrin (73.11%) and MgT(4-Cl)PP (75.89%).

Graphical abstract: Histamine-bound magnesium porphyrins: diverse coordination modes, inhibitory role in photodegradation of chlorophyll a and antioxidant activity

Supplementary files

Article information

Article type
Paper
Submitted
03 Maijs 2023
Accepted
08 Jūl. 2023
First published
19 Jūl. 2023

Dalton Trans., 2023,52, 11085-11095

Histamine-bound magnesium porphyrins: diverse coordination modes, inhibitory role in photodegradation of chlorophyll a and antioxidant activity

A. K. Choudhury, R. Sarkar and J. Bhuyan, Dalton Trans., 2023, 52, 11085 DOI: 10.1039/D3DT01309J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements