| Abstract
| - The preparation of the first photochromic, organometallic derivative of the diarylethene class,the CpRu-complexed benzodimethyldihydropyrene 3, in which the organometallic is directly attached tothe photochromic core, is described. The negative dark purple photochrome 3 readily bleaches to form thealmost colorless cyclophanediene 3‘ on irradiation with visible light. The latter switches back to 3 eitherphotochromically with UV light, electrochromically on reduction, or thermochromically on heating. Essentiallyquantitative conversion between the two states is possible. The open complex 3‘ thermally closes 2.6 timesfaster than the uncomplexed parent 2‘, but the closed form 3 opens with visible light at about 30% of therate of uncomplexed 2. Both open forms, complexed 3‘ and uncomplexed 2‘ close equally fast with UVlight.
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