Interligand Charge-Transfer Interactions in Electroactive Coordination Frameworks Based on N, N'-Dicyanoquinonediimine (DCNQI)

Robert W Elliott; Pavel M Usov; Brendan F Abrahams; Bun Chan; Richard Robson; Deanna M D'Alessandro

doi:10.1021/acs.inorgchem.8b00130

Interligand Charge-Transfer Interactions in Electroactive Coordination Frameworks Based on N, N'-Dicyanoquinonediimine (DCNQI)

Inorg Chem. 2018 Aug 20;57(16):9766-9774. doi: 10.1021/acs.inorgchem.8b00130. Epub 2018 Apr 9.

Authors

Robert W Elliott¹, Pavel M Usov², Brendan F Abrahams¹, Bun Chan^{2

3}, Richard Robson¹, Deanna M D'Alessandro²

Affiliations

¹ School of Chemistry , The University of Melbourne , Victoria , Australia 3010.
² School of Chemistry , The University of Sydney , New South Wales , Australia 2006.
³ Graduate School of Engineering , Nagasaki University , Bunkyo 1-14 , Nagasaki 852-8521 , Japan.

PMID: 29629755
DOI: 10.1021/acs.inorgchem.8b00130

Abstract

Coordination frameworks containing DCNQI^2- (DCNQI = N, N'-dicyanoquinonediimine ligand) are produced by deprotonation of DCNQIH₂ in the presence of a metal center and a co-ligand. This approach has yielded two-dimensional (2D) sheet compounds [Cd(DCNQI)(L)₂] (where L = pyridine (py) or isoquinoline (isoquin)) that can be partially oxidized via solid-state electrochemical and in situ spectroelectrochemical methods to materials that contain DCNQI as its radical monoanion. The new frameworks display charge-transfer bands that are indicative of interligand charge-transfer interactions as supported by TD-DFT computational calculations. The redox-state dependent spectral properties of the frameworks have been probed using a newly developed solid-state spectroelectrochemical cell. Coupled with computational calculations, the experimental data provide an understanding of the fundamental charge-transfer processes that may underpin long-range functional properties such as conductivity in framework materials.