Electrically Activated Conductivity and White Light Emission of a Hydrocarbon Nanoring–Iodine Assembly

Abstract

Numerous otherwise difficult applications have been realized with materials, the chemical/physical properties of which can be controlled by external stimuli such as heat, pressure, photo‐irradiation, and voltage bias. However, the complexity of design and the lack of easy‐to‐conduct synthetic methods make the creation of on‐demand stimuli responsive materials a formidable task. Here we report an electric‐stimuli‐responsive multifunctional material, [10]CPP‐I: crystalline assembly of a hydrocarbon nanoring ([10]cycloparaphenylene: [10]CPP) as an “electro‐responsive porous host” and iodine as a “potentially functional molecule”. Through applying electric stimulus, [10]CPP‐I turned to exhibit two attractive properties: electronic conductivity and white light emission. We revealed that electric stimuli trigger the cascade formation of polyiodide chains inside the [10]CPP assembly through charge transfer, leading to the emergence of these properties. This “responsive porous host” approach is expected to be applicable for different stimuli, and opens the path for devising a generic strategy to the development of stimuli‐responsive materials.

Supramolecular Organization in Confined Nanospaces

“…Beside interesting structural aspects, dihalogens, when forced into nanosized spaces, may reveal unexpected behavior, especially when the confining matrix is stimuli‐responsive. One such matrices, formed by condensed organic rings, contains I 2 chains similar to those found in zeolites . Upon activation with an electric field, the system displayed electronic conductivity, ascribed to polyiodide chains formed by charge transfer from the organic matrix (Figure ).…”

“…Although the polymerization process has not been clarified yet, the conductivity was found to depend on the size of the ring. This suggests that the dynamics of confined I 2 molecules may play a relevant role in the process …”

“…Electric stimulation of this host‐guest system generates electronic conductivity (from iodine chains) and white light emission (from the organic matrix). Reprinted with permission from Wiley‐VCH …”

Supramolekulare Chemie von gespannten Kohlenstoffnanoreifen

“…In einer eleganten Studie zur Nutzung der porösen Kanäle im festen Zustand cokristallisierten Itami, Sakamoto und Mitarbeiter Iod mit Nanoreifen [9]CPP , [10]CPP und [12]CPP und beobachteten die Zunahme der Leitfähigkeit (ca. 10 6 Ω cm spezifischer Widerstand bei Vorspannung von 500 mV) und Weißlichtemission des festen Materials “ [10]CPP ‐I” . Die Autoren kamen durch die Kombination von spektroskopischen Techniken zu dem Schluss, dass die Bildung von Polyiodidketten und der daraus resultierende Ladungsaustausch zwischen [10]CPP ‐Röhren und verkapselten Iodketten zu diesen bemerkenswerten Eigenschaften führt (Abbildung a).…”

“… a) Phasenübergang der Verbindung aus [10]CPP und Iod durch elektrischen Stimulus, übernommen aus Lit. mit der Genehmigung von Wiley‐VCH, Copyright (2017). b) 12F‐[12]CPP zeigt nicht‐kovalente Selbstorganisation im Festkörper, übernommen aus Lit.…”