meta-Oligoazobiphenyls – synthesis via site-selective Mills reaction and photochemical properties

Abstract

SummaryThe investigation of multi-photochromic compounds constitutes a great challenge, not only from a synthetic point of view, but also with respect to the analysis of the photochemical properties. In this context we designed a novel strategy to access meta-oligoazobiphenyls via site-selective Mills reaction and Suzuki cross-coupling in a highly efficient iterative way. Photochemical examination of the resulting monomeric and oligomeric azo compounds revealed that the overall degree of switching was independent of the connected azo-units. However, one of the azobonds in the bis-azobiphenyl is isomerized preferentially despite the high structural similarity.

Oxidative Approach Enables Efficient Access to Cyclic Azobenzenes

“…Among peracetic acid, meta -chloroperoxybenzoic acid ( m CPBA), and magnesium monoperoxyphthalate (MMPP), we found that m CPBA performed best. The use of mCPBA to prepare nitrosobenzenes from anilines is well precedented . A screen of solvent mixtures revealed that diluting acetic acid with DCM or toluene resulted in a further increased yield, although a sizable fraction of acetic acid was necessary for optimal results.…”

Computational design of a molecular triple photoswitch for wavelength-selective control

“…While in this work static quantum chemical calculations are sufficient to demonstrate the concept of meta-connectivity and the computational design of a first triple-photoswitch based on azobenzene, in general nuclear quantum dynamics are required to study the efficiency of photoswitching and to determine timescales and relevant loss channels. In the future we plan to synthesize and spectroscopically investigate the suggested meta -trisazobenzene derivatives in analogy to previous works 49–51. This work indeed paves the way for future development of selectively photoswitchable control systems being used in advanced materials and nano-electronic devices.…”

Azo-Dyes-Grafted Oligosaccharides—From Synthesis to Applications

“…However, the simplest way for the symmetrical oxidative coupling is to use the air oxygen [ 41 , 42 , 43 , 44 ]. Mills reaction allows also oxidative coupling from anilines, but leading to unsymmetrical azobenzenes [ 45 , 46 , 47 , 48 , 49 , 50 ].…”