The formation and detailed spectroscopic characterization of the first biuret-containing monoanionic superoxido-NiII intermediate [LNiO2 ]- as the Li salt [2; L=MeN[C(=O)NAr)2 ; Ar=2,6-iPr2 C6 H3 )] is reported. It results from oxidation of the corresponding [Li(thf)3 ]2 [LNiII Br2 ] complex M with excess H2 O2 in the presence of Et3 N. The [LNiO2 ]- core of 2 shows an unprecedented nucleophilic reactivity in the oxidative deformylation of aldehydes, in stark contrast to the electrophilic character of the previously reported neutral Nacnac-containing superoxido-NiII complex 1, [L'NiO2 ] (L'=CH(CMeNAr)2 ). According to density-functional theory (DFT) calculations, the remarkably different behaviour of 1 versus 2 can be attributed to their different charges and a two-state reactivity, in which a doublet ground state and a nearby spin-polarized doublet excited-state both contribute in 1 but not in 2. The unexpected nucleophilicity of the superoxido-NiII core of 2 suggests that such a reactivity may also play a role in catalytic cycles of Ni-containing oxygenases and oxidases.
- Klíčová slova
- dioxygen ligands, nickel, structure elucidation, structure-activity relationships, two-state reactivity,
- MeSH
- komplexní sloučeniny chemie MeSH
- kvantová teorie MeSH
- kyslík chemie MeSH
- lithium chemie MeSH
- molekulární modely MeSH
- nikl chemie MeSH
- oxidace-redukce MeSH
- oxidoreduktasy chemie MeSH
- oxygenasy chemie MeSH
- soli chemie MeSH
- superoxidy chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Názvy látek
- komplexní sloučeniny MeSH
- kyslík MeSH
- lithium MeSH
- nikl MeSH
- oxidoreduktasy MeSH
- oxygenasy MeSH
- soli MeSH
- superoxidy MeSH
