Ruthenium dinitrosyl complexes – computational characterization of structure and reactivity

<div><p>Elucidation of the electronic structure of a dinitrosyl dithiolate ruthenium complex in several formal oxidation states ranging from Ru(I) to Ru(III) has been undertaken. DFT and <i>ab initio</i> molecular dynamics simulations have shown clear evidence of asymmetry within the dinitrosyl moieties in all models though most noticeably in the excited states. The reaction pathway of a hyponitrite adduct formation was also examined and found to be more feasible in the excited states. These results, along with the recently reported study on the dinitrosyl dithiolate iron analog of these complexes, provide insight toward the mechanism of NO donation by dinitrosyl metal complexes.</p></div

Studies of reaction of tetramethylthiourea with hydrogen peroxide: evidence of formation of tetramethylthiourea monoxide as a key intermediate of the reaction

<p>The reaction between tetramethylthiourea (TMTU) and hydrogen peroxide was studied by UV–VIS spectroscopy, ESI mass spectrometry, ¹H NMR, cyclic voltammetry and surface-enhanced Raman scattering. We found that the reaction includes two consecutive steps, that is, (i) an oxidation of TMTU to TMTU monoxide (TMTMO) and (ii) further oxidation of TMTU monoxide to tetramethylurea (TMU) and sulfate. The second step is complex and seems to include extrusion of sulfur monoxide (SO). Density functional theory calculations were employed on tetramethylthiourea oxide models in order to underline differences between monoxide and di- and trioxides. Calculations predict that the TMTMO structure can be best explained as an adduct of thiourea with an oxygen atom (═S–>O).</p