New NMR investigation of [RuF5NO]2− anion

Solid-State Photo-NMR Study on Light-Induced Nitrosyl Linkage Isomers Uncovers Their Structural, Electronic, and Diamagnetic Nature

“…This hypothesis is verified by comparing 15 N spectra acquired at three different fields (14.1, 11.8 , and 7.1 T) and by measuring a sample dissolved in DMSO-d 6 (see Figure S3), where only one pair of lines is observed with a splitting similar to what is measured in the crystals: 2 J( 15 N− 19 F) = 70.3 Hz. Additionally, the spin− spin coupling between 15 N and 19 F (F in the position trans to 15 NO) was also observed in [Ru( 15 NO)F 5 ] 2− in D 2 O with a value of 2 J( 15 N− 19 F) = 67 Hz, 45 in the same range as our result. Because of the relatively small chemical shift difference of 15 N for the A and B cations, the assignment of the doublets to the cations A (δ iso = −38.6 ppm) and B (δ iso = −37.6 ppm) could not be achieved by DFT calculations.…”

“…As expected from literature data, 18,21,28,45,46 the isotropic chemical shift values of δ iso ( 15 N) in the GS and MS1 are lying in the range of −8 up to −40 ppm, which confirms the linearity of the Ru−N−O and Ru−O−N axes, shown already by X-ray structure analysis. 26 From the complete tensor δ ij ( 15 N), we observe that no asymmetry of the chemical shift components (δ xx = δ yy ) is present so that η = 0, implying axial symmetry of the electron density around the 15 N. The asymmetry of the 19 F chemical shielding (η = 0.4/0.5 for A/B) on the 19 F atom can be explained by the asymmetry in the geometry of the hydrogen intramolecular contacts with 19 F (Figure 3).…”

“…2 J( 15 N− Ru− 19 F) = 70.5 Hz to 3 J( 15 N−O−Ru− 19 F) = 105 Hz, despite the fact that in MS1, due to the inversion of the NO ligand, the 19 F− 15 N connection increases by one chemical bond. As found in the literature, similar ruthenium nitrosyl complexes in the octahedral configuration with a linear Ru−N−O configuration show15 N chemical shifts in the range of δ iso = −8 to −40 ppm 18,21,28,45,46. Values outside this window would indicate a significantly bent Ru−N−O structure because this distortion induces strong downfield shifting of the 15 N chemical shifts.…”

NMR spectroscopic investigations of transition metal complexes in organometallic and bioinorganic chemistry

“…Bent M(NO À ) complexes typically exhibit δ N values over +350 ppm, while linear M(NO + ) complexes show δ N values below +200 ppm. [196][197][198][199][200][201][202][203] The 15 N NMR spectra of transition metal-dinitrogen (M (N 2 )) complexes display distinctive features compared with free N 2 (δ N = À75 ppm), 204 as the δ N values of N α and N β can be significantly different (Figure 4g). Similar to M(CO) complexes, the δ N values of N α atoms in M(N 2 ) complexes are strongly affected by the type of the metal center, while those of N β atoms are less sensitive.…”

“…These M–N–O bond angles strongly correlate with δ N values, enabling 15 N NMR spectroscopy to differentiate metal–nitrosyl complexes depending on the NO oxidation states (Figure 4g). Bent M(NO − ) complexes typically exhibit δ N values over +350 ppm, while linear M(NO + ) complexes show δ N values below +200 ppm 196–203 …”