Localized mixed-valence and redox activity within a triazole-bridged dinucleating ligand upon coordination to palladium

Broere, D. L. J., Plessius, R., Tory, J., Demeshko, S., de Bruin, B., Siegler, M. A., Hartl, F. ORCID: https://orcid.org/0000-0002-7013-5360 and van der Vlugt, J. I. (2016) Localized mixed-valence and redox activity within a triazole-bridged dinucleating ligand upon coordination to palladium. Chemistry- A European Journal, 22 (39). pp. 13965-13975. ISSN 1521-3765 doi: 10.1002/chem.201601900

Abstract/Summary

The new dinucleating redox-active ligand (LH4), bearing two redox-active NNO-binding pockets linked by a 1,2,3-triazole unit, is synthetically readily accessible. Coordination to two equivalents of PdII resulted in the formation of paramagnetic (S=inline image ) dinuclear Pd complexes with a κ2-N,N′-bridging triazole and a single bridging chlorido or azido ligand. A combined spectroscopic, spectroelectrochemical, and computational study confirmed Robin–Day Class II mixed-valence within the redox-active ligand, with little influence of the secondary bridging anionic ligand. Intervalence charge transfer was observed between the two ligand binding pockets. Selective one-electron oxidation allowed for isolation of the corresponding cationic ligand-based diradical species. SQUID (super-conducting quantum interference device) measurements of these compounds revealed weak anti-ferromagnetic spin coupling between the two ligand-centered radicals and an overall singlet ground state in the solid state, which is supported by DFT calculations. The rigid and conjugated dinucleating redox-active ligand framework thus allows for efficient electronic communication between the two binding pockets.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/66561
Identification Number/DOI	10.1002/chem.201601900
Refereed	Yes
Divisions	Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Publisher	Wiley
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