Crystal Structure of 2-Trifluoromethyl-4′-dimethylaminoazobenzene

• Published in: Analytical Sciences ; X-ray Structure and Analysis Online Vol. 19; pp. x1 - x2
• Main Authors: SASAKI, Chizuru, KITOH, Soh-ichi, YAMADA, Kazuya, KUNIMOTO, Ko-Ki, MAEDA, Shiro, KUWAE, Akio, HANAI, Kazuhiko
• Format: Journal Article
• Language: English
• Published: Tokyo The Japan Society for Analytical Chemistry 2003; Japan Science and Technology Agency
• ISSN: 1348-2238; 1348-2238; 1883-3578
• DOI: 10.2116/analscix.19.x1

Crystals of 2-trifluoromethyl-4′-dimethylaminoazobenzene (2-TFMDAB) are orthorhombic, space group Pbca with a =15.625(4), b = 23.028(6), c = 7.685(2)Å, and Z = 8. The structure was solved by direct methods (SIR88) and refined to a final R value of 0.049 for 2536 reflections (I>0.80σ(I)). 2-TFMDAB has a trans geometry about the azo linkage. The bond lengths and angles are similar to those of other azobenzene compounds. The abnormal UV-vis absorption spectrum in an acidic solution can be explained by the existence of the bulky and electronegative CF3 group at the 2-position, which prevents protonation at the Nβ atom of the azo group in an acidic solution.