The semiquinone radical anion of 1,10-phenanthroline-5,6-dione: synthesis and rare earth coordination chemistry

James R Hickson,Jake Mcguire,Stephen Sproules,Joy H Farnaby,Claire Wilson,Samuel J Horsewill

doi:10.1039/c8cc05591b

James R Hickson, Jake Mcguire + Show 4 more

Open Access

https://doi.org/10.1039/c8cc05591b

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Abstract

Reduction of 1,10-phenanthroline-5,6-dione (pd) with CoCpR2 resulted in the first molecular compounds of the pd˙- semi-quinone radical anion, [CoCpR2]+[pd]˙- (R = H, (1); R = Me4, (2)). Furthermore compounds 1 and 2 were reacted with [Y(hfac)3(thf)2] (hfac = 1,1,1-5,5,5-hexafluoroacetylacetonate) to synthesise the rare earth-transition metal heterometallic compounds, [CoCpR2]+[Y(hfac)3(N,N'-pd)]˙- (R = H, (3); R = Me4, (4)).

Highlights

Electron transfer reactions are fundamental to chemical processes
The number of examples of f-elements complexed to redox-active ligands or radical anions is still modest but this is a growing area of research activity; for magnetism, multi-electron transfer chemistry and functional materials.[4,8]
We demonstrate the coordination chemistry of 1 and 2, with [Y(hfac)3(thf)2] to synthesise the rare earth-transition metal heterometallic compounds, [CoCpR2]+[Y(hfac)3(N,N0-pd)]À (R = H, (3); R = Me4, (4))

Summary

Introduction

There is literature precedent for the formation of multimetallic complexes using the dianionic form of the ligand.[9,10,11,12] We recently reported heterometallic rare earth-transition metal complexes utilising pd as a template.[13] Our two-step route was necessary because pd is reported to react with a number of reducing agents, the products are insoluble in common solvents, precluding collection of spectroscopic data and definitive assignment of redox state, but more importantly further reactivity.[11,14,15] Scheme 2 Synthetic route to radical anion containing rare-earth transition metal complexes.

Results

Conclusion