Issue 13, 2018

Redox and photocatalytic properties of a NiII complex with a macrocyclic biquinazoline (Mabiq) ligand

Abstract

We present a late, first row transition metal photosensitizer that promotes photocatalytic C–C bond formation. The title compound, [Ni(Mabiq)]OTf, as well as its one-electron reduced form, Ni(Mabiq), were synthesized and molecular structures of both were obtained. The electronic structure of the reduced complex additionally was characterized by spectroscopic and DFT computational methods. Notably, [NiII(Mabiq)]OTf is photoactive: reduction of the compound was achieved photochemically upon irradiation at λ = 457 nm and reductive quenching by NEt3. The performance of [Ni(Mabiq)]OTf as a photoredox catalyst was examined in the cyclization of a bromoalkyl-substituted indole. In this reaction, the first-row transition metal compound is comparable if not superior to [Ru(bpy)3]2+ in terms of efficiency (turnover number) and chemoselectivity. Studies using a series of sacrificial donor amines indicate that the excited state redox potential of [Ni(Mabiq)]+* is ≥1.25 V vs. SCE. This value is similar to the excited state potential of commonly employed noble metal based photocatalysts. The Ni-Mabiq compound thus provides a rare example of an earth-abundant photoredox catalyst.

Graphical abstract: Redox and photocatalytic properties of a NiII complex with a macrocyclic biquinazoline (Mabiq) ligand

Supplementary files

Article information

Article type
Edge Article
Submitted
15 dec 2017
Accepted
20 feb 2018
First published
23 feb 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2018,9, 3313-3317

Redox and photocatalytic properties of a NiII complex with a macrocyclic biquinazoline (Mabiq) ligand

M. Grübel, I. Bosque, P. J. Altmann, T. Bach and C. R. Hess, Chem. Sci., 2018, 9, 3313 DOI: 10.1039/C7SC05320G

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, 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 commercial 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