Novel photochromism of propargylallene in the solid state

Abstract

2-[2,7-Dibromo-9-(3-oxo-3-phenyl-prop-1-ynyl)-9H-fluoren-9-yl]-3-fluoren-9-ylidene-1-phenyl-propenone (1) shows photochromism from pale yellow to green in the solid state, whereas 3-(2,7-dibromo-fluoren-9-ylidene)-2-[9-(3-oxo-3-phenyl-prop-1-ynyl)-9H-fluoren-9-yl]-1-phenyl-propenone (2) does not show any photochromism