Synthesis and photoisomerization study of new aza-crown macrocyclic tweezer tethered through an azobenzene linker: The first report on supramolecular interaction of azobenzene moiety with C-60

摘要

In the present communication, three bimacrocyclic tweezers linked through azobenzene moiety, L-n (n = 1-3) were synthesized in a multistep route and characterized by x-ray crystallography, IR, H-1 and C-13 NMR, UV-vis spectroscopy as well as CHN microanalysis. UV-visible spectroscopy established that the irradiation of L-1 and L-3 with UV light promoted the trans to cis isomerization. Irradiating the reaction mixtures with Hg lamp, significant supramolecular interactions between L-1 and L-3 with C-60 were also found in terms of the association constants calculated by UV-visible spectroscopy, denoting on more pronounced interaction with C-60 that in the absence of UV light. The molecular structures of L-1-L-3 calculated by using DFT method suggested a novel unprecedented interaction between the HOMO's of azobenzene moiety on the tweezer instead of the aromatic groups with C-60. (C) 2017 Elsevier B.V. All rights reserved.