Thermally reversible photochromic behaviour of new naphthopyrans involving an intramolecular [2+2] cyclization reaction
作者:Paulo J. Coelho、Luís M. Carvalho、Gaston Vermeersch、Stephanie Delbaere
DOI:10.1016/j.tet.2009.04.070
日期:2009.7
New 4-(2,2-diphenylethenyl)naphthopyrans were synthesized and their photochromic behaviour in solution were studied under continuous UV light irradiation conditions. Although only one coloured photoproduct was expected to be formed, due to the naphthopyran substitution pattern, NMR analysis on degassed UV irradiated solutions, performed at low temperature, showed the formation of different compounds
合成了新的4-(2,2-二苯基乙烯基)萘并吡喃并在连续紫外光照射条件下研究了它们在溶液中的光致变色行为。尽管由于萘并吡喃的取代模式,预计仅会形成一种彩色的光产物,但在低温下对脱气的UV辐射溶液进行的NMR分析表明形成了不同的化合物。其中,主要产物是通过分子内[2 + 2]环化反应形成的,并且具有热可逆的光致变色特性。