Facile O-atom insertion into C-C and C-H bonds by a trinuclear copper complex designed to harness a singlet oxene.
Two trinuclear copper [Cu(I)Cu(I)Cu(I)(L)](1+) complexes have been prepared with the multidentate ligands (L) 3,3'-(1,4-diazepane-1,4-diyl)bis(1-((2-(dimethylamino)ethyl)(methyl)amino)propan-2-ol) (7-Me) and (3,3'-(1,4-diazepane-1,4-diyl)bis(1-((2-(diethylamino) ethyl)(ethyl) amino)propan-2-ol) (7-Et) as models for the active site of the particulate methane monooxygenase (pMMO). The ligands were designed to form the proper spatial and electronic geometry to harness a "singlet oxene," according to the mechanism previously suggested by our laboratory. Consistent with the design strategy, both [Cu(I)Cu(I)Cu(I)(L)](1+) reacted with dioxygen to form a putative bis(mu(3)-oxo)Cu(II)Cu(II)Cu(III) species, capable of facile O-atom insertion across the central C-C bond of benzil and 2,3-butanedione at ambient temperature and pressure. These complexes also catalyze facile O-atom transfer to the C-H bond of CH(3)CN to form glycolonitrile. These results, together with our recent biochemical studies on pMMO, provide support for our hypothesis that the hydroxylation site of pMMO contains a trinuclear copper cluster that mediates C-H bond activation by a singlet oxene mechanism.
Chen
Peter P-Y
PP
Institute of Chemistry, Academia Sinica, Nankang, Taipei, Taiwan 115, Republic of China.
Yang
Richard B-G
RB
Lee
Jason C-M
JC
Chan
Sunney I
SI
D001665:Binding Sites; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003931:Diacetyl / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D004852:Epoxy Compounds / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D008024:Ligands; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry*; D010658:Phenylglyoxal / Q000031:analogs & derivatives / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared