Indeno[1, 2‐b]fluorene‐Based [2, 2]Cyclophanes with 4n/4n and 4n/[4n+2] π Electrons: Syntheses, Structural Analyses, and Excitonic Coupling Properties. (13th June 2019)

• Record Type: Journal Article
• Authors: Wang, Chi‐Shin; Wei, Yu‐Chen; Chang, Kai‐Hsin; Chou, Pi‐Tai; Wu, Yao‐Ting
• Is Part Of: Angewandte Chemie. Volume 131:Number 30(2019)
• Page Start: 10264
• Page End: 10268
• Publication Date: 2019-06-13
• Subjects: Aromatizität -- Cyclophane -- Elektronische Struktur -- Nichtkovalente Wechselwirkungen -- Strukturaufklärung; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201903561
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Indeno[1, 2‐ b ]fluorene‐based [2, 2]cyclophanes with 4 n /4 n and 4 n /[4 n +2] π‐electron systems were prepared, and their structures were identified by X‐ray crystallography. With short π–π distances around 3.0 Å, [2.2](5, 11)indeno[1, 2‐ b ]fluorenophane and its precursor [2.2](5, 11)indeno[1, 2‐ b ]fluorene‐6, 12‐dionophane exhibit remarkable transannular interactions, leading to their unusual electrochemical and photophysical properties. With the aid of femtosecond transient absorption spectroscopy, the transition from the monomeric excited state to the redshifted H‐type dimeric state was first observed, correlating to the calculated excitonic energy splitting and the steady‐state absorption spectra induced by charge‐transfer‐mediated superexchange interaction. Abstract : Exotische Elektronenkonfiguration : anti ‐[2.2](5, 11)Indeno[1, 2‐ b ]fluorenophan weist ein seltenes 20/20‐π‐Elektronensystem auf. Die Verbindung zeigt bemerkenswerte transannulare Wechselwirkungen, die zu photophysikalischen, elektrochemischen und photodynamischen Eigenschaften führen. Ein Übergang vom monomeren angeregten Zustand zum dimeren rotverschobenen H‐Typ‐Zustand wird erstmals beobachtet.