Synthesis, crystal structure, and photoreaction of a disiloxane bearing two 2-(phenylazo)phenyl groups

An E,E-1,1,3,3-tetrafluoro-1,3-bis[2-(phenylazo)phenyl]-1,3-disiloxane (E,E-2) was synthesized by hydrolysis of E-trifluoro[2-(phenylazo)phenyl]silane (E-1). Its structure was characterized by 1H-, 13C-, 19F-, and 29Si-NMR spectroscopy and X-ray crystallographic analysis showing two pentacoordinate silicon atoms with SiN interactions. Photoirradiation of E,E-2 caused both isomerization of the azo group and formation of the corresponding Z-1 in a short time, while upon standing in the dark the E-1 was formed very slowly.