Abstract

Conjugated metallopolymers give direct access to a wide range of special electronic properties inferred by the metal center, e.g. enhanced spin-orbit coupling and stable redox chemistry.1,2 Polymetallaynes are a special class of strongly conjugated Wolf type-III polymers3 with high potential in organic electronics. However, polymetallaynes with redox-active transition metals are rarely reported, and lack the solubility needed for processing. Yet studies on oligo-nuclear redox-active metal-acetylide complexes demonstrated high conductivity,4,5 and the association of a Fe(III) metal center was shown to boost charge mobility of a semiconducting polymer, and to increase the cycling stability of the fabricated OFE Ts We recently established the synthetic routes to a Ru-containing polymetallyne P[Ru(dppe)2-DDBT],6 containing Ru(II) centers bridged in trans-position. The polymer was obtained by copper-free dehydrohalogenation, characterized using NMR , IR and UV-vis spectroscopy, MALDI , GPC and CV. In solution, CV studies show two separated metal-centered redox processes, indicating that the charge between metal centers is delocalized via the bridging ligand and a mixed-valence species exists (Kc = 102). In thin-film, P[Ru(dppe)2-DDBT] exhibits a single oxidation wave with higher peak current intensity, consistent with a two-electron process and localized charge. Despite a degree of polymerization >32 based on NMR and GPC studies, P[Ru(dppe)2-DDBT] is fully solution processable. Thin-films were obtained via spin-coating using, and AFM investigations showed very low surface roughness. First OFET devices with top-gate bottom-contact (TGBC) architecture were fabricated to characterize the electronic properties, confirming semiconducting behaviour with low hole mobility up to 1×10−4 cm2V-1s-1.

References (1) B. J. Holliday and T. M. Swager, Chem. Commun., 2005, 23–36; (2) T. M. Swager, Macromolecules, 2017, 50, 4867–4886. (3) M. O. Wolf, J. Inorg. Organomet. Polym. Mater., 2006, 16, 189–199, (4) F. Schwarz, G. Kastlunger, F. Lissel, H. Riel, K. Venkatesan, H. Berke, R. Stadler and E. Lörtscher, Nano Lett., 2014, 14, 5932–5940; (5)Y. Tanaka, Y. Kato, T. Tada, S. Fujii, M. Kiguchi and M. Akita, J. Am. Chem. Soc., 2018, 140, 10080–10084: (6) P. Ho, H. Komber, K. Horatz, T. Tsuda, S. Mannsfeld, E. Dmitrieva, O. Blacque, U. Kraft, H. Sirringhaus and F. Lissel, Polymer Chemistry 2019, accepted.