Patent ID: 7355775

Claim:
A photochromic compound which is a diarylethene-containing coordination compound in which the diarylethene contains part of a mono-cyclic ring structure with one or more donor atom(s) or heteroatom(s) coordinated to a coordination unit [M], which contains an acceptor atom, M, expressed by the general formula (I): where unit B represents a mono-cyclic ring structure that comprises phenanthroline and contains two nitrogen, n is 1, [M] represents a coordination unit containing an acceptor atom M, R 1 and R 6 individually represent an alkyl group or an alkoxy group, and R 2 to R 5 individually represent atoms or groups selected from the group of hydrogen atom, halogen atom, hydroxyl group, alkyl group, alkoxy group, cyano group, nitro group, alkylcarbonyl group, alkoxycarbonyl group, perfluoroalkyl group, aryl group, cycloalkyl group, arylcarbonyl group, aryloxycarbonyl group, mono- or dialkylaminocarbonyl group, alkylcarbonyloxy group, arylcarbonyloxy group, aryloxy group, alkoxycarbonyl group, and aryloxycarbonyloxy group.