Projektbeschreibung
Cyclacene, ringförmige Kohlenstoffverbindungen, erstmals synthetisiert
Cyclacene sind ringförmige polyzyklische Verbindungen, bei denen die aromatischen Anteile zu Ringstrukturen verschmolzen sind. Die einzigartigen chemischen, elektronischen und strukturellen Eigenschaften dieser ringförmigen Kohlenstoffverbindungen machen sie für den Einsatz in der organischen Elektronik und Spintronik interessant. Trotz jahrzehntelanger Forschungsanstrengungen ist es bisher nicht gelungen, auch nur einen einzigen Vertreter dieser Stoffklasse herzustellen. Das ERC-finanzierte Projekt TACY wird neue synthetische Strategien zur Herstellung von Cyclacenen entwickeln. Der vorgeschlagene Ansatz ist hochgradig modular und erlaubt es, die gürtelartigen Vorstufen und damit die Cyclacene strukturell zu variieren, indem verschiedene Substituenten an den Rändern angebracht werden. Die Projektforschung wird in Verbindung mit modernsten Berechnungen und molekularen Charakterisierungsverfahren einen noch nie dagewesenen Einblick in die Struktur-Eigenschafts-Beziehung der konjugierten Zickzack-Topologie in Cyclacenen geben.
Ziel
Cyclacenes, i.e. cyclic versions of acenes consisting of linearly fused benzene rings, were first discussed in 1954 by Heilbronner, but - despite considerable synthetic efforts over decades - have remained an elusive class of compounds. Theoretical investigations suggest that cyclacenes are highly reactive due to pronounced polyradical character and significant ring strain. All prior attempts to synthesise cyclacenes failed, mainly because the final synthetic step of establishing a fully conjugated π-system was energetically prohibitive. Despite these challenges, cyclacenes remain intriguing synthetic targets because of their unique chemical, electronic, and structural properties as well as their potential applications in organic (opto-)electronics or spintronics. In this collaborative project, we will develop novel synthetic approaches, which synergistically combine efficient and high-yielding synthetic strategies of belt-type precursors that we will transform to cyclacenes by extrusion of suitable leaving groups under cryogenic matrix isolation conditions, on surfaces, in the solid state, and ultimately even in solution. Our synthetic approach is highly modular and allows to structurally vary the belt-type precursors, and thus the cyclacenes, by placing different substituents at the rims, including peri-annulation or isosteric substitution of CH units by heteroatoms. This research, combined with state-of-the-art computational investigations and characterization even on the single-molecule level, will provide unprecedented insight into the structure-property relationship of the fully conjugated zigzag topology present in cyclacenes and address fundamental questions of chemical reactivity and the interplay of aromaticity, strain and polyradical character. This knowledge will finally allow us to synthesise interlocked structures based on cyclacenes and to apply cyclacenes in controlled reactions on surfaces for creating further elusive materials such as polyacenes.
Wissenschaftliches Gebiet
Schlüsselbegriffe
Programm/Programme
- HORIZON.1.1 - European Research Council (ERC) Main Programme
Thema/Themen
Finanzierungsplan
ERC-SYG - ERC-SYGGastgebende Einrichtung
69117 Heidelberg
Deutschland