Kim Sunghee, Lee Jung Yoon, Cowley Ryan E, Ginsbach Jake W, Siegler Maxime A, Solomon Edward I, Karlin Kenneth D
Department of Chemistry, Johns Hopkins University , Baltimore, Maryland 21218, United States.
J Am Chem Soc. 2015 Mar 4;137(8):2796-9. doi: 10.1021/ja511504n. Epub 2015 Feb 20.
Previous efforts to synthesize a cupric superoxide complex possessing a thioether donor have resulted in the formation of an end-on trans-peroxo-dicopper(II) species, {(Ligand)Cu(II)}2(μ-1,2-O2(2-)). Redesign/modification of previous N3S tetradentate ligands has now allowed for the stabilization of the monomeric, superoxide product possessing a S(thioether) ligation, ((DMA)N3S)Cu(II)(O2(•-)) (2(S)), as characterized by UV-vis and resonance Raman spectroscopies. This complex mimics the putative Cu(II)(O2(•-)) active species of the copper monooxygenase PHM and exhibits enhanced reactivity toward both O-H and C-H substrates in comparison to close analogues (L)Cu(II)(O2(•-)), where L contains only nitrogen donor atoms. Also, comparisons of (L)Cu(II/I) compound reduction potentials (L = various N4 vs (DMA)N3S ligands) provide evidence that (DMA)N3S is a weaker donor to copper ion than is found for any N4 ligand-complex.
此前合成具有硫醚供体的铜超氧化物配合物的尝试，导致形成了一种端基反式过氧二铜（II）物种，即{(配体)Cu(II)}2(μ-1,2-O2(2-))。对先前的N3S四齿配体进行重新设计/修饰，现在已能够稳定具有S（硫醚）配位的单体超氧化物产物((DMA)N3S)Cu(II)(O2(•-))（2(S)），这通过紫外可见光谱和共振拉曼光谱得以表征。该配合物模拟了铜单加氧酶PHM假定的Cu(II)(O2(•-))活性物种，并且与仅含有氮供体原子的类似物(L)Cu(II)(O2(•-))相比，对O-H和C-H底物均表现出增强的反应活性。此外，(L)Cu(II/I)化合物还原电位的比较（L = 各种N4与(DMA)N3S配体）提供了证据，表明(DMA)N3S作为铜离子供体比任何N4配体配合物都弱。
