Optical Switching and Fluorescence Modulation Properties of Photochromic Metal Complexes Derived from Dithienylethene Ligands

✍ Scribed by Alvaro Fernández-Acebes; Jean-Marie Lehn

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 167 KB
• Volume: 5
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/(sici)1521-3765(19991105)5:11<3285::aid-chem3285>3.0.co;2-q

✦ Synopsis

Organic photochromic systems represent a starting point for the preparation of light-triggered molecular switching devices. The novel dithienylethene-tungsten (1,2), rhenium (3,4), and ruthenium (5) complexes were synthesized from their parent ligands. The biscyano photochromic complexes 14 and 16 were also prepared although their metallic complexes could not be isolated. All the compounds described exhibited pronounced photochromic proper-ties. Irradiation of the open forms of complexes 1 ± 4 with UV light resulted in essentially quantitative photocyclization to the deeply colored closed forms; the colorless open forms could be regenerated by irradiation with visible light of l b 600 nm. Compounds 1 ± 4 were found to display a fluorescence discrimination between their open and closed

forms when excited at wavelengths (240 nm) that almost did not affect the state of the system. Finally the closed form of product 5, prepared from the closed form of its parent ligand, was photochemically stable. Thus, the molecules 1 ± 5 represent two kinds of nondestructive read-out models.