Redox induced S–S bond cleavage of 2,2′-dithiobisbenzothiazole – leading to a [2Ru-2S] core analogous to [2Fe-2S] cluster

Abstract

Facile reduction of 2,2-dithiobisbenzothiazole by the mediation of metal-to-ligand charge transfer or by internal reducing equivalent was demonstrated. It led to varying binding modes of thiolates (1, 2, ) in...

Structural and Electronic Diversity as a Function of Metal Ions and Co‐ligands in Deprotonated Epindolidione Bridged Diruthenium and Diosmium Set‐up

“…Ruthenium(III) derived paramagnetic 1 and 2 (μ/BM: 1 , 2.80 and 2 , 2.92 in CDCl 3 at 300 K, Evans method, Table S3, Supporting Information) displayed well‐defined 1 H NMR resonances over a wide chemical shift region of δ, +7 to −41 ppm in CDCl 3 (Figure 3 and Experimental Section), due to the combined effect of Fermi contact [23] and pseudo contact [24] shifts as revealed by variable temperature NMR profile (Figure 4). The distinct shift of CH 3 /CH(acac) protons of 1 / 2 (δ/ppm≈ ‐2 to ‐40) towards the higher and lower δ values with the increase (20 °C to 50 °C) and decrease (20 °C to −50 °C) in temperature suggestive of Fermi contact and pseudo contact shifts, respectively [23,24a] . The partial delocalization of spin density onto the acac units of 1 / 2 in Figure 10 (see below) could be originated due to the empty e g set of low‐spin Ru III ( t 2g 5 , e g 0 ) [24] .…”

“…5 , e g 0 ). [24] The diastereomeric meso-1 and rac-2 exhibited similar 1 H NMR signature corresponding to the full molecule in each case with slight variation in chemical shift values. [25] 1 H NMR spectra of meso-diastereomeric [3](ClO 4 ) 2 and [4](ClO 4 ) 2 showed 20 and 44 proton resonances corresponding to the half and full molecules, respectively.…”

“…On the contrary, crystals of the earlier reported meso-[5](ClO 4 ) 2 and meso-[6](ClO 4 ) 2 failed to display any such non-covalent interactions. [13] Spectral features Ruthenium(III) derived paramagnetic 1 and 2 (μ/BM: 1, 2.80 and 2, 2.92 in CDCl 3 at 300 K, Evans method, Table S3, Supporting Information) displayed well-defined 1 H NMR resonances over a wide chemical shift region of δ, + 7 to À 41 ppm in CDCl 3 (Figure 3 and Experimental Section), due to the combined effect of Fermi contact [23] and pseudo contact [24] shifts as revealed by variable temperature NMR profile (Figure 4). The distinct shift of CH 3 /CH(acac) protons of 1/2 (δ/ppm � -2 to -40) towards the higher and lower δ values with the increase (20 °C to 50 °C) and decrease (20 °C to À 50 °C) in temperature suggestive of Fermi contact and pseudo contact shifts, respectively.…”

Inner-sphere electron transfer at the ruthenium-azo interface

“…On the other hand, oxidised paramagnetic [ 2 ]ClO 4 showed broad 1 H-NMR resonances over a wide chemical shift range of δ = ±40 ppm due to contact and pseudo-contact shift effects. 15 The one-electron paramagnetic features of oxidised [ 2 ]ClO 4 (Ru III -abim˙ − -Ru III , S = 1/2) due to the antiferromagnetic coupling of one of the Ru( iii ) ions and the abim radical were corroborated based on the Evans method 16 ( μ eff = 1.78 BM in CDCl 3 at 298 K, see ESI†) and on its metal-based anisotropic EPR spectrum, with 〈 g 〉/Δ g = 2.141/0.541 (Fig. 4 and Table 2).…”