9,10-Dihydrophenanthrene with Two Spiro(dibenzocycloheptatriene) Units : A Highly Strained Caged Hydrocarbon Exhibiting Reversible Electrochromic Behavior

• Ishigaki, Yusuke

• Hayashi, Yuki

• Sugawara, Kazuma

• Shimajiri, Takuya

• Nojo, Wataru

• Katoono, Ryo

• Suzuki, Takanori

Abstract

The title dispiro hydrocarbon 1 was designed as a new electrochromic material. This multiply clamped hexaphenylethane-type electron donor was prepared from 2,2'-diiodobiphenyl via biphenyl-2,2'-diylbis(dibenzotropylium) 2(2+) salt. X-ray analysis of 1 revealed a highly strained structure as reflected by an elongated ethane bond [bond length: 1.6665(17) angstrom] and nearly eclipsed conformation. The weakened bond was cleaved upon two-electron oxidation to regenerate the deeply colored dication 2(2+). The reversible interconversion between 1 and 2(2+) is accompanied not only by a drastic color change but also by C-C bond formation/cleavage. Thus, the voltammogram showed a pair of well-separated redox waves, which is characteristic of "dynamic redox (dyrex)" behavior. The tetrahydro derivative of 1 with two units of spiro(dibenzocycloheptadiene), which suffers from more severe steric congestion, was also prepared. The crystallographically determined bond length for the central C-C bond [1.705(4) angstrom] is greatest among the values reported for 9,9,10,10-tetraaryl-9,10-dihydrophenanthrene derivatives.

Journal

• Molecules

  Molecules 22 (11), 1900-, 2017-11

  MDPI

Keywords

• polycyclic aromatic hydrocarbons
• long bond
• dynamic redox system
• dication
• dibenzotropylium
• electrochromism
• through-bond interaction

Details

• CRID: 1050282676657161216
• NII Article ID: 120006383818
• DOI: 10.3390/molecules22111900
• HANDLE: 2115/68293
• ISSN: 14203049
• Web Site: http://www.mdpi.com/1420-3049/22/11/1900/pdf
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN