A Large Starphene Comprising Pentacene Branches

TL;DR

This paper reports a novel synthesis method for a large, stable [16]starphene compound with confirmed structure and properties, advancing materials for organic electronics and optics.

Contribution

A new solid-state synthesis strategy for pristine [16]starphene, enabling scalable production and detailed structural and electronic characterization.

Findings

Successful synthesis of [16]starphene in preparative scale

Structural confirmation via high-resolution STM

Evidence of moderate electronic delocalization

Abstract

Starphenes are attractive compounds due to their characteristic physicochemical properties that are inherited from acenes, making them interesting compounds for organic electronics and optics. However, the instability and low solubility of larger starphene homologs make their synthesis extremely challenging. Herein, we present a new strategy leading to pristine [16]starphene in preparative scale. Our approach is based on a synthesis of a carbonyl-protected starphene precursor that is thermally converted in a solid-state form to the neat [16]starphene, which is then characterised with a variety of analytical methods, such as 13C CP-MAS NMR, TGA, MS MALDI, UV-Vis and FTIR spectroscopy. Furthermore, high-resolution STM experiments unambiguously confirm its expected structure and reveal a moderate electronic delocalisation between the pentacene arms. Nucleus-independent chemical shifts NICS(1) are also calculated to survey its aromatic character.