Issue 11, 2021

Copper(ii) complexes of N-propargyl cyclam ligands reveal a range of coordination modes and colours, and unexpected reactivity

Abstract

The coordination chemistry of N-functionalised cyclam ligands has a rich history, yet cyclam derivatives with pendant alkynes are largely unexplored. This is despite the significant potential and burgeoning application of N-propargyl cyclams and related compounds in the creation of diversely functionalised cyclam derivatives via copper-catalysed azide–alkyne ‘click’ reactions. Herein we describe single crystal X-ray diffraction and spectroscopic investigations of the coordination chemistry of copper(II) complexes of cyclam derivatives with between 1 and 4 pendant alkynes. The crystal structures of these copper complexes unexpectedly reveal a range of coordination modes, and the surprising occurrence of five unique complexes within a single recrystallisation of the tetra-N-propargyl cyclam ligand. One of these species exhibits weak intramolecular copper-alkyne coordination, and another is formed by a surprising intramolecular copper-mediated hydroalkoxylation reaction with the solvent methanol, transforming one of the pendant alkynes to an enol ether. Multiple functionalisation of the tetra-N-propargyl ligand is demonstrated via a ‘tetra-click’ reaction with benzyl azide, and the copper-binding behaviour of the resulting tetra-triazole ligand is characterised spectroscopically.

Graphical abstract: Copper(ii) complexes of N-propargyl cyclam ligands reveal a range of coordination modes and colours, and unexpected reactivity

Supplementary files

Article information

Article type
Paper
Submitted
30 Okt 2020
Accepted
21 Jän 2021
First published
08 Feb 2021

Dalton Trans., 2021,50, 3931-3942

Copper(II) complexes of N-propargyl cyclam ligands reveal a range of coordination modes and colours, and unexpected reactivity

A. J. Counsell, M. Yu, M. Shi, A. T. Jones, J. M. Batten, P. Turner, M. H. Todd and P. J. Rutledge, Dalton Trans., 2021, 50, 3931 DOI: 10.1039/D0DT03736B

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