Seminar: A/Prof Deanna D'Alessandro - Exploring Charge Transfer in Electroactive Coordination Frameworks

Thursday, 26 April 2018 - 12:00pm – Thursday, 26 April 2018 - 1:00pm  |  CHEMSCI M10

Speaker: A/Prof Deanna D'Alessandro

Electroactive coordination frameworks (aka Metal‐Organic Frameworks (MOFs)) offer a fundamental platform to explore electron transfer phenomena within 3‐dimensional coordination space. At the applied level, these materials have enormous potential as the basis for electrochromic devices, electrocatalysts, porous conductors, batteries and solar energy harvesting systems, amongst numerous other potential applications.1

This presentation will detail our latest findings in the design and synthesis of electroactive MOFs that integrate molecular components for electron transfer including radical ligands and mixed‐valence metal centres. The insights gained into fundamental charge transfer phenomena of relevance to understanding biological photosynthetic systems and porous semiconductors will be discussed (Fig. 1). Key to our investigations have been solid‐state AC/DC electrochemical methods in addition to solid‐ state near‐IR/Vis, EPR and Raman spectroelectrochemical (SEC) techniques that have been developed in our laboratory, providing powerful in situ probes for the optical and electron transfer characteristics of MOFs.2,3 These methods are potentially relevant to exploring electroactivity and fundamental charge transfer phenomena in a wide range of other materials (e.g., supramolecular systems, battery materials, etc). Our work on the DFT computational modelling of the electronic and optical properties of these systems will also be described, providing an important link between experiment and theory. Single crystal transmission measurements have enabled quantification of the charge transfer properties and application of theoretical models such as Marcus‐Hush theory for the first time in application to framework systems.4

Selected References:

1. D.M. D’Alessandro, “Exploiting Redox Activity in Metal‐Organic Frameworks: Concepts, Trends and Perspectives,” Chem. Commun., 2016, 8957‐8971.

2. C.F. Leong, B. Chan, T.B. Faust and D.M. D’Alessandro, “Donor‐Acceptor Charge Transfer in a Novel Tetrathiafulvalene‐ Naphthalene Diimide Metal‐Organic Framework,” Chem. Sci., 2014, 5, 4724‐2728. 

3. P.M. Usov, C. Fabian and D.M. D’Alessandro, “Rapid Determination of the Optical and Redox Characteristics of a Metal‐ Organic Framework via Solid State Spectroelectrochemistry,” Chem. Commun., 2012, 48, 3945‐3947.

4. C. Hua, P. Doheny, B. Ding, B. Chan, C.J. Kepert, D.M. D’Alessandro, “Through‐Space Intervalence Charge Transfer as a Mechanism for Charge Delocalisation in Metal‐Organic Frameworks,” J. Am. Chem. Soc., just accepted.