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

Photoreversible Molecular Motion of stpyCN Coordinated to fac-[Re(CO)3(NN)]+ Complexes

“…1 IL NN (for comparison, electronic spectra of noncoordinated NN ligands are shown in Figure S15 in the Supporting Information). The intense band from 330 to 420 is assignedby comparison with precursor’s spectra, Figures S16 and S17 in the Supporting Informationto an overlap between 1 MLCT Re→NN and 1 IL stpyCN transitions, similarly observed for other fac -[Re­(CO) 3 (NN)­( trans -L)] + complexes. ,,,,,,,− , …”

“…A remarkable Φ cis → trans of 0.22 ± 0.02 was observed for both cis - 1 and cis - 2 , thus the photoresponsive trans ⇌ cis molecular motion of fac -[Re­(CO) 3 (NN)­( trans -L)] + systems exhibits an efficient reversibility, which is a characteristic of the fac- [Re­(CO) 3 (NN)­(stpyCN)] + series , (Tables S6 and S11 in the Supporting Information list the complete triplicate data). Worth noticing, the Φ cis → trans values were determined for the photostationary solution, in which trans- and cis- isomers are competing for the light absorption; thus, the Φ cis → trans true might be even higher for pure (100%) cis -solutions.…”

“…This photophysical behavior was never reported for photoisomerizable fac -[Re­(CO) 3 (NN)­(L)] + complexes and seems to be intrinsic of the stpyCN rhenium­(I) series. Therefore, we extended the photophysical characterization for fac -[Re­(CO) 3 (phen)­(stpyCN)] + and fac -[Re­(CO) 3 (ph 2 phen)­(stpyCN)] + obtaining additional emission spectra in PMMA, Figure E–H.…”

“…In our previous works, syntheses and photocharacterization of fac -[Re­(CO) 3 (NN)­(stpyCN)] + complexes (NN = 1,10-phenanthroline (phen) or 7,4-diphenyl-1,10-phenanthroline (ph 2 phen); stpyCN = 4-(4-cyano)­styrylpyridine) were performed for the understanding of molecular-level photocontrolled motions. , In this work, the photochemical and photophysical behavior of new fac -[Re­(CO) 3 (bpy)­( trans -stpyCN)]­PF 6 ( trans- 1 ) and fac -[Re­(CO) 3 (dmb)­( trans -stpyCN)]­PF 6 ( trans - 2 ) compounds, Chart , were investigated in order to obtain further insights of the excited state dynamics that govern the photoprocesses of fac -[Re­(CO) 3 (NN)­(stpyCN)] + series.…”

Synthesis, characterization, photophysical and electrochemical properties of fac-tricarbonyl(4,7-dichloro-1,10-phenanthroline)rhenium(I) complexes

“…Additionally, intense effort has been dedicated to better understand the effect of the position and attachment of electron withdrawing/donating groups to ligands on the mechanistic events after excitation 15,[17][18][19][20][21] , which can contribute to a deeper comprehension of their emissive properties. For instance, electron withdrawing groups attached to polypyridyl ligands promote stabilization of 3 MLCT Re→NN excited state energy level (metal-to-ligand charge-transfer) 15,17,19,[21][22][23][24] . On the other hand, electron donating groups, such as methyl, promote destabilization of 3 MLCT Re→NN excited state energy level and at the same time reduces the energy of ligand-centered excited state, 3 IL NN 19,21,23 .…”