Journal article

Authors list: Reuter, R; Wegner, HA

Publication year: 2011

Pages: 2987-2995

Journal: Chemistry - A European Journal

Volume number: 17

Issue number: 10

ISSN: 0947-6539

DOI Link: https://doi.org/10.1002/chem.201002671

Publisher: Wiley

Abstract: 
We report an efficient synthesis of cyclotris[(E)-3'-(biphenyl-3-yldiazenyl)] compounds (CTBs). An unsubstituted CTB molecule is accessible in four steps in 10% yield overall, whereas a hexa(methoxymethyl ether) CTB analogue was prepared in nine steps (26% yield). The final macrocyclization step was accomplished in up to 80% yield by using a metal-template effect. Furthermore, the photochromic properties were investigated, and all four isomers were detected and characterized by NMR spectroscopy. A strong influence from the solvent and the irradiation wavelength on the switching process was observed. Irradiation in pyridine yielded the highest amount of the all-Z isomer in the photostationary state. For a full conversion to the all-E isomer, the reaction has to be heated to 45 degrees C. The isomerization to the all-E isomer is slow at room temperature, with a half-life time of the all-Z isomer of more than nine days in dimethyl sulfoxide (DMSO). Conditions were established to access each possible isomer as the major component in the photostationary state.

Harvard Citation style: Reuter, R. and Wegner, H. (2011) Synthesis and Isomerization Studies of Cyclotrisazobiphenyl, Chemistry - A European Journal, 17(10), pp. 2987-2995. https://doi.org/10.1002/chem.201002671

APA Citation style: Reuter, R., & Wegner, H. (2011). Synthesis and Isomerization Studies of Cyclotrisazobiphenyl. Chemistry - A European Journal. 17(10), 2987-2995. https://doi.org/10.1002/chem.201002671