Optomechanical trans-to-cis and cis-to-trans isomerization and unusual photophysical behavior of fac-[Re(CO)3(phen)(CNstpy)]

• Published in: Inorganic chemistry communications 2012-06, Vol.20, p.105-107
• Main Authors: Frin, Karina P.M., Zanoni, Kassio P.S., Murakami Iha, Neyde Y.
• Format: Article
• Language: English
• Subjects: Photochemistry; Photophysics; Rhenium; Stilbene-like ligand photoisomerization; True quantum yield
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2012.02.028

Unusual high photoassisted quantum yields for cis-to-trans (Φ254 nm=0.27±0.05) isomerization of CNstpy coordinated to fac-[Re(CO)3(phen)(CNstpy)]+ were determined along with trans-to-cis ones (Φ313 nm=0.58±0.02; Φ365 nm=0.61±0.06; Φ404 nm=0.42±0.02). Additionally, in contrast to other similar rhenium(I) complexes, the cis photoproduct is quasi non-emissive and comparable to the trans-complex. The cis-to-trans photoisomerization is due to the deactivation from the ILcis-CNstpy excited state in competition to the usual 3MLCTRe→phen luminescence. These efficient cis to trans and trans to cis photoisomerization can be conveniently used in light powered molecular machines. The Graphical Abstract summarizes all photoisomerization quantum yields determined for fac-[Re(CO)3(phen)(CNstpy)]+, as well as the trans- and cis-complex structures. It evidences the capacity of changing the majoritarian isomer by changing the incident light energy. These efficient cis to trans and trans to cis photoisomerization can be conveniently used in light powered molecular machines. [Display omitted] ► Efficient photoresponsive Re(I) compound applicable in molecular machines. ► trans/cis apparent and true photoisomerization quantum yields for fac-[Re(CO)3(phen)(CNstpy)]+. ► Unusual photophysical properties of fac-[Re(CO)3(phen)(cis-CNstpy)]+.