Details

Autor(en) / Beteiligte

• Everhart, Stephanie C.
• Jayasundara, Udaya K.
• Kim, HyunJong
• Procúpez-Schtirbu, Rolando
• Stanbery, Wayne A.
• Mishler, Clay H.
• Frost, Brian J.
• Cline, Joseph I.
• Bell, Thomas W.

Titel

Synthesis and Photoisomerization of Substituted Dibenzofulvene Molecular Rotors

Ist Teil von

• Chemistry : a European journal, 2016-08, Vol.22 (32), p.11291-11302

Ort / Verlag

Germany: Blackwell Publishing Ltd

Erscheinungsjahr

2016

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• The synthesis, spectral and structural characterization, and photoisomerization of a family of 2‐substituted dibenzofulvene molecular actuators based on (2,2,2‐triphenylethylidene)fluorene (TEF) are reported. The 2‐substituted species investigated are nitro (NTEF), cyano (CTEF), and iodo (ITEF). X‐ray structures of these three compounds and three intermediates were determined to assign alkene configuration and investigate the effects of the 2‐substituents on steric gearing. The addition–elimination reaction of Z‐9 with trityl anion to form Z‐10 proceeded with complete retention of configuration. Rates of photoisomerization were measured at irradiation wavelengths between 266–355 nm in acetonitrile/dioxane solutions at room temperature. Photoisomerization quantum yields (φ) were calculated by means of a mathematical model that accounts for a certain degree of photodecomposition in the cases of CTEF and ITEF. Quantum yields vary significantly with substituent, having maximum values of φ=0.26 for NTEF, 0.39 for CTEF, and 0.50 for ITEF. NTEF is photochemically robust and has a large quantum yield for photoisomerization in the near‐UV, making it a particularly promising drive rotor moiety for light‐powered molecular devices. A useful twist: 2‐Substituted dibenzofulvene molecular actuators based on (2,2,2‐triphenylethylidene)fluorene are reported. The 2‐nitro compound is photochemically robust and has a large quantum yield for photoisomerization in the near‐UV, making it a promising drive rotor moiety for light‐powered molecular devices. The 2‐cyano and 2‐iodo analogues (E and Z isomers of the latter shown in picture) have higher quantum yields but absorb light at shorter wavelengths and undergo minor competing photodecomposition.