Abstract
Two tolylazoimidazole derivatives, N 1 -(2-naphthylmethyl)-2-(p-tolylazo)imidazole and N 1 ,N 3 -bis(2-naphthylmethyl)-2-(p-tolylazo)imidazolium perchlorate containing the 2-naphthylmethyl substituted groups were prepared and characterised by EA, IR, ESI-MS and NMR spectroscopy. The crystal structure of N 1 ,N 3 -bis(2-naphthylmethyl)-2-(p-tolylazo)imidazolium perchlorate was determined by X-ray diffraction. The photo responsive results showed that N 1 -(2-naphthylmethyl)-2-(p-tolylazo) imidazole present perfectly reversible trans–cis photoisomerisation by irradiation at 365 nm and 456 nm, with significantly lower quantum yield 0.19 and 0.04. However, N 1 ,N 3 -bis(2-naphthylmethyl)-2-(p-tolylazo)imidazolium perchlorate does not undergo photoisomerisation.