ABSTRACT
A strategic methodology has been developed to effectively synthesize the fac-[Re(CO)3(dcbH2)( trans-stpy)]+ complex, where dcbH2 = 2,2'-bipyridine-4,4'-dicarboxylic acid and trans-stpy = trans-4-styrylpyridine, which has been designed to efficiently absorb visible light. The complex exhibits outstanding trans-to- cis photoisomerization with 436 nm irradiation (Φ transâ cis = 0.50 ± 0.03), in contrast to the photochemical behavior previously reported in the literature (Faustino, L. A.; et al. Inorg. Chem. 2018, 57, 2933-2941). The main emphasis here is to address the synthetic strategy for obtaining the actual complex, its characterization, and an accurate description of its photochemical and photophysical behavior, which reveal new insights into this complex.
ABSTRACT
In this work, efficient trans â cis photoswitchings of 4-(4-cyano)styrylpyridine (stpyCN) coordinated to organometallic bipyridyl tricarbonyl rhenium(I) complexes, fac-[Re(CO)3(NN)( trans-stpyCN)]+, where NN = 2,2'-bipyridine (bpy) or 4,4'-dimethyl-2,2'-bipyridine (dmb), are described. For both complexes, the true trans-to- cis quantum yields determined by 1H NMR spectroscopy are similar at 313, 334, and 365 nm irradiations (Φ transâ cistrue(313-365 nm) â¼ 0.45), with a small decrease at 404 nm (Φ transâ cistrue(404 nm) â¼ 0.37). The investigated complexes also exhibit significant quantum yields for the reversible cis-to- trans photoreactions (Φ cisâ trans(255 nm) = 0.22). The luminescent properties of these complexes were also analyzed in different media to elucidate a key role of the 3ILstpyCN state in photophysical and photochemical processes, giving new insights on their intriguing photobehavior.