Positive and negative photochromism of novel spiro[indoline-phenanthrolinoxazines]

A series of new spirooxazines (SPO) containing phenanthroline were synthesized and their photochromic properties were investigated. Photoisomerization of the spirooxazine was facilitated by electron donating groups in the indole moiety, a polar solvent and metal complexation. Their complexes (PMC)3Ni2+ were very stable at room temperature and exhibited excellent negative photochromism.