We explore new concepts in the design and synthesis of functional aromatic molecules that can be used as organic battery electrode materials and in organic electronics. Our research is not limited to a specific compound class but covers conjugated small molecules, macrocycles and polymers. If necessary for achieving the synthesis of our target compounds, we also develop new synthetic methods.
Conjugated molecules hold great promise for becoming the next generation of battery electrode materials. These next generation materials are critically needed to meet the rising demand for electrochemical energy storage, to replace battery electrodes based on heavy metals such as cobalt, and to enable the transition from lithium ions to more abundant alternatives. While promising specific capacities were achieved with some aromatic organic compounds, they often suffer from significant degradation issues when tested under fast-charge/discharge conditions. Fundamentally new concepts are needed for solving these issues and for designing stable organic materials with excellent redox properties.
Π-CONJUGATED MACROCYCLES
We design and synthesize redox-active macrocycles for battery electrodes and other applications. The intrinsic porosity of the macrocycles can facilitate the diffusion of ions in the material, an important feature for battery electrodes and various other applications that rely on both electron and ion transport, such as electrochromic devices, light-emitting electrochemical cells, and electrochemical transistors.
Excellent redox properties can be achieved by designing conjugated macrocycles capable of switching between locally and globally aromatic states, as we have recently shown.
(a) Molecular structure and reduction of disodium terephthalate. (b) Molecular structure and reduction of [2.2.2.2]paracyclophane-1,9,17,25-tetraene (PCT); bold bonds indicate the conjugated periphery of 4n π-electrons in the neutral state and 4n+2 π-electrons in the reduced state.
Exemplary publication:
S. Eder, D.-J. Yoo, W. Nogala, M. Pletzer, A. Santana Bonilla, A. J. P. White, K. E. Jelfs, M. Heeney, J. W. Choi,* F. Glöcklhofer*
Angew. Chem., Int. Ed. 2020, 59, 12958-12964. DOI:10.1002/anie.202003386
Angew. Chem. 2020, 132,13058-13064. DOI:10.1002/ange.202003386
[Link, open access]
SYNTHETIC METHODS
We develop new synthetic methods to facilitate the preparation of known aromatic organic compounds and to enable the preparation and study of new derivatives. Although aromatic organic compounds have been widely studied as materials for organic electronics and other applications, many particularly interesting compounds cannot be synthesized using available methods or are difficult to obtain.
Recently, we reported a double ring-closing approach for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain.
Synthesis of 2,3,6,7-substituted anthracene derivatives by intermolecular Wittig reaction and subsequent deprotection and intramolecular double ring-closing condensation reaction.
Exemplary publication:
Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives
B. Meindl, K. Pfennigbauer, B. Stöger, M. Heeney, F. Glöcklhofer*
J. Org. Chem. 2020, 85, 8240-8244. DOI:10.1021/acs.joc.0c00826