A Cu( i ) fully fluorinated O-donor monodentate alkoxide complex, K[Cu(OC 4 F 9 ) 2 ], was previously shown to form a trinuclear copper–dioxygen species with a {Cu 3 (μ 3 -O) 2 } core, T OC4F9 , upon reactivity with O 2 at low temperature. Herein is reported a significantly expanded kinetic and mechanistic study of T OC4F9 formation using stopped-flow spectroscopy. The T OC4F9 complex performs catalytic oxidase conversion of hydroquinone (H 2 Q) to benzoquinone (Q). T OC4F9 also demonstrated hydroxylation of 2,4-di- tert -butylphenolate (DBP) to catecholate, making T OC4F9 the first trinuclear species to perform tyrosinase (both monooxygenase and oxidase) chemistry. Resonance Raman spectra were also obtained for T OC4F9 , to our knowledge, the first such spectra for any T species. The mechanism and substrate reactivity of T OC4F9 are compared to those of its bidentate counterpart, T pinF , formed from K[Cu(pin F )(PR 3 )]. The monodentate derivative has both faster initial formation and more diverse substrate reactivity.
Cu( i )–O 2 oxidation reactions in a fluorinated all-O-donor ligand environment
Investigation of Cu–O 2 oxidation reactivity is important in biological and anthropogenic chemistry. Zeolites are one of the most promising Cu/O based oxidation catalysts for development of industrial-scale CH 4 to CH 3 OH conversion. Their oxidation mechanisms are not well understood, however, highlighting the importance of the investigation of molecular Cu( i )–O 2 reactivity with O-donor complexes. Herein, we give an overview of the synthesis, structural properties, and O 2 reactivity of three different series of O-donor fluorinated Cu( i ) alkoxides: K[Cu(OR) 2 ], [(Ph 3 P)Cu(μ-OR) 2 Cu(PPh 3 )], and K[(R 3 P)Cu(pin F )], in which OR = fluorinated monodentate alkoxide ligands and pin F = perfluoropinacolate. This breadth allowed for the exploration of the influence of the denticity of the ligand, coordination number, the presence of phosphine, and K⋯F/O interactions on their O 2 reactivity. K⋯F/O interactions were required to activate O 2 in the monodentate-ligand-only family, whereas these connections did not affect O 2 activation in the bidentate complexes, potentially due to the presence of phosphine. Both families formed trisanionic, trinuclear cores of the form {Cu 3 (μ 3 -O) 2 } 3− . Intramolecular and intermolecular substrate oxidation were also explored more »
- Award ID(s):
- 1800313
- Publication Date:
- NSF-PAR ID:
- 10097315
- Journal Name:
- Dalton Transactions
- Volume:
- 48
- Issue:
- 15
- Page Range or eLocation-ID:
- 4759 to 4768
- ISSN:
- 1477-9226
- Sponsoring Org:
- National Science Foundation
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- https://doi.org/10.1039/C8DT05028G
