Photoinduced linkage isomers in a model ruthenium nitrosyl complex: Identification and assignment of vibrational modes

The influence of the trans-ligand to NO on the thermal stability of the photoinduced side-bond coordinated linkage isomer

“…Recently, it was shown for the [RuNOPy 4 F] 2+ cation that ν (Ru–(NO)) and δ(Ru–(N–O)) modes in GS may have merely the same energy, but are essentially split in the case of MS1 and MS2. 42 NO isomerization leads to the downshift of ν (Ru–(NO)) and δ (Ru–(N–O)) vibrations in the case of MS1 for about 125 cm −1 compared to GS, while the downshift of ν (Ru–(NO)) is relatively larger. In RuF, the ν (Ru–(NO)) mode of MS2 is downshifted as well, whereas δ (Ru–(N–O)) energies of MS2 of RuOH and RuCl are much closer to those of GS, which is expected from calculations.…”

“…In RuF, the ν (Ru–(NO)) mode of MS2 is downshifted as well, whereas δ (Ru–(N–O)) energies of MS2 of RuOH and RuCl are much closer to those of GS, which is expected from calculations. 42 Because the Ru–X bond length is decreased after NO ligand isomerization, 10,27 the energy of the corresponding ν (Ru–X) mode is increased. In the case of RuOH, the bands at 642 and 668 cm −1 are tentatively assigned to the ν (Ru–OH) mode of GS and MS1, respectively.…”

“…The changes in the low energy range of the spectra (700-400 cm À1 ) are listed in Table 3 and calculations. 42 Because the Ru-X bond length is decreased after NO ligand isomerization, 10,27 the energy of the corresponding n(Ru-X) mode is increased. In the case of RuOH, the bands at 642 and 668 cm À1 are tentatively assigned to the n(Ru-OH) mode of GS and MS1, respectively.…”

Ruthenium-nitrosyl complexes as NO-releasing molecules, potential anticancer drugs, and photoswitches based on linkage isomerism

“…14 While linkage isomers are mostly observed in the solid-state, photorelease of NO is in general studied in solutions, even though NO release was also reported in the solid-state highlighting the reactivity and particularity of the NO ligand in this respect. 17,122,123 Furthermore, there is an ongoing discussion as to whether linkage isomers might be involved in the NO photorelease mechanism. 124 With respect to applications, nitrosyl linkage isomers have been considered for information storage due to the absorptive and photorefractive changes occurring upon their photogeneration, 23,125 but also for fast optical correlation techniques 126 or switchable nonlinear optics.…”

“…As pointed out by Talotta et al, 138 based on CASPT calculations, the photodissociation of NO is a two-step sequential process coupled to a partial population of the MS2 side-on isomer. The above described recent progress in understanding of the photoisomerization mechanism as well as the detection of NO release in the solid state 17,122,123 opens the way to investigate the competition between these two processes.…”