Lest we Forget - the Importance of Heteroatom Interactions in Heterocyclic Conjugated Systems, from Synthetic Metals to Organic Semiconductors.

The field of synthetic metals was, and remains, highly influential for the development of organic semiconductor materials. Yet, with the passing of time and the rapid development of conjugated materials in recent years, the link between synthetic metals and organic semiconductors is at risk of being forgotten. In this review, we reflect on one of the key concepts developed in synthetic metals - heteroatom interactions. The application of this strategy in recent organic semiconductor materials, small molecules and polymers, is highlighted, with analysis of X-ray crystal structures and comparisons with model systems used to determine the influence of these non-covalent short contacts. The case is made that the wide range of effective heteroatom interactions and the high performance that has been achieved in devices from organic solar cells to transistors is testament to the seeds sown by the synthetic metals research community. This article is protected by copyright. All rights reserved.