A Versatile Cyclic 2,2′-Azobenzenophane with a Functional Handle and Its Polymers: Efficient Synthesis and Effect of Topological Structure on Chiroptical Properties

• Published in: Chemistry : a European journal 2015-02, Vol.21 (6), p.2324-2329
• Main Authors: Lu, Jinjie, Xia, Aiyou, Zhou, Nianchen, Zhang, Wei, Zhang, Zhengbiao, Pan, Xiangqiang, Yang, Yonggang, Wang, Yong, Zhu, Xiulin
• Format: Article
• Language: English
• Subjects: azo compounds; Azo Compounds - chemical synthesis; Azo Compounds - chemistry; Bridges (structures); Chemical industry; Chemical reactions; Chemistry; chirality; Circular Dichroism; cyclic compounds; Derivatives; Dichroism; Handles; Molecular Conformation; Optical Rotation; photoisomerization; Polymers; Polymers - chemical synthesis; Polymers - chemistry; Quantum Theory; Rings (mathematics); Spectrophotometry, Ultraviolet; Stereoisomerism; Topology
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201405940

Two novel cyclic azobenzenophanes (SC, RC) with functional handles have been synthesized efficiently by a Glaser coupling reaction. Through a Suzuki coupling reaction, alternating ring/linear polymers with rigid (conjugated)/flexible (unconjugated) bridges were obtained from the resultant cyclic azobenzenophanes. The optical activities of linear, cyclic, and macromolecular binaphethyl–azobenzene derivatives were investigated by UV/Vis and circular dichroism (CD) spectra and the time‐dependent (TD)‐DFT method. Experimental results and theoretical analyses indicated that the cyclic configurations exhibited better chiroptical features than the others, and the reverse conformation and difference of dextro‐/levo‐rotation of azobenzenophanes were detected by comparing linear and cyclic structures, which provides an opportunity for the optical‐rotation‐controlled “smart” materials systems in future. Smart chemistry! Three azobenzenophanes of different topological structures (linear, cyclic, alternating ring/linear) were synthesized with high yields. Reverse conformation and different dextro (positive)/levo (negative) rotation were detected in the cyclic structures and their linear precursors (see scheme). Chiroptical properties of the alternating ring/linear polymers depended on the bridge chains.