Interplay between magnetism and photochromism in spiropyran-MnPS3 intercalation compounds

N-Methylated pyridospiropyran cations SP-R+ (R = Me, Ph) have been inserted into MnPS3 by ion exchange to yield Mn1-xPS3(SP-R)(2x) intercalates. Thin transparent films of these materials have been processed, which exhibit pho tochromism due to spiropyran-merocyanin transformation. Intercalation consi derably stabilizes the merocyanin form. When R = Me, the films are stable i n the dark over months. Such a strong stabilization may be due to the forma tion of J-aggregates within the weakly polar interlayer medium of the MnPS3 host lattice. The modifications of the basal spacing associated with photo chromism have been characterized. One of the two intercalates (R = Me) acqu ires a spontaneous magnetization below about 40 K. Irradiation does not cha nge T, but considerably affects the hysteresis loop, increasing remanence a nd coercitivity.