Synthesis and Property Studies of Cyclotrisazobenzenes

Abstract

Azobenzenophanes are fascinating macrocycles, which are of special interest due to their unique photochromic behavior. Cyclotrisazobenzenes 2 (R = H, Br, tBu) were prepared to probe how much strain the photoisomerization of the azobenzene motive can tolerate. The macrocycles were synthesized in an overall yield of 10-20 % from ortho-phenylenediamine

Selective switching of multiple azobenzenes

“…The syntheses of the azobenzene macrocycles were designed in a straight-forward manner relying on Baeyer–Mills reactions,25,26 Cu( i )-catalyzed oxidative couplings of anilines27 and oxidative macrocyclization reactions 19,28. The 2,2-bis(4-aminophenyl)propane starting material 4 can be readily obtained from aniline hydrochloride and acetone 29.…”

Control of the Orientation and Photoinduced Phase Transitions of Macrocyclic Azobenzene

“…In particular, we have been interested in the effect of macrocyclic structures, in which multiple azobenzene chromophores are tethered together by covalent bridges. These molecules show interesting properties such as multistate photoswitching properties,20 molecular hinge‐like motion,21 and self‐assembly in crystal,20i, j, 22 LC,11, 23 and gel24 states.…”

Oligoazobenzenes – Switching in a New Dimension

“…2), [10] we initiated a research program to investigate the efficient preparation and the properties of such macrocycles. [11] Since the overall yield of the reported synthesis of cyclotrisazobenzene was low, a new and efficient synthetic strategy was developed. This approach also allows the introduction of functional groups.…”