Copper-dioxygen adducts and the side-on peroxo dicopper(II)/bis(mu-oxo) dicopper(III) equilibrium: Significant ligand electronic effects.
Copper-dioxygen adducts and the side-on peroxo dicopper(II)/bis(mu-oxo) dicopper(III) equilibrium: Significant ligand electronic effects.
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DOI：
10.1021/ic052185m
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发表时间：
2006-03
影响因子：
4.6
通讯作者：
Lanying Q. Hatcher;M. Vance;Amy A. Narducci Sarjeant;E. Solomon;K. Karlin
中科院分区：
文献类型：
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作者：
Lanying Q. Hatcher;M. Vance;Amy A. Narducci Sarjeant;E. Solomon;K. Karlin
研究了三齿胺铜(I)配合物吡啶基上配体对取代基的变化，探讨了电子效应对mu-eta2:eta2-（侧对）-过氧[Cu(II)2(O2(2-))]2+和与O2反应形成的双（mu-oxo） [Cu(III)2(O(2-))2]之间平衡的影响。[铜(I) (R-PYAN) (MeCN) n] B (C6F5) 4 (R-PYAN = n - [2 - (4-R-pyridin-2-yl)乙基]- n, n ', n ' -trimethyl-propane-1, 3-diamine, R = NMe2,中耳炎,H,和Cl) (1 R)在一个狭窄的范围内不同的铜(II) /铜(I)氧化还原电位(E(1/2)和铁(cp) 2 (+ / 0) = 1 (NMe2) -0.40 V, -0.38 V 1(渗出性中耳炎),-0.33 V 1 H,和-0.32 V 1 Cl)和切断拉伸频率羰基的加合物,1 r-co:ν(切断)= 2080,2086,2088,和2090厘米(1)R = NMe2,中耳炎,H,分别和Cl。然而，在1R的电子性质范围内，二氧反应性受到显著影响。在-78℃下，1Cl或1H与O2在CH2Cl2中反应，得到的紫外可见光谱和共振拉曼光谱表明了-eta2:eta2-（侧对）-过氧铜（II）加合物（2R）。化合物1（OMe）与O2反应，生成侧对过氧（2(OMe)）和双氧（mu-oxo） （3(OMe)）的平衡混合物。1（NMe2）的氧化作用导致双（mu-氧）铜（III）络合物（3(NMe2)）的唯一生成。还观察到溶剂效应；在丙酮或四氢呋喃中，观察到双氧（mu-氧）相对于侧对过氧络合物的比例增加。因此，可以通过配体设计来调节双铜侧对过氧和双氧（mu-oxo）之间的平衡，特别是，更多的供电子配体有利于后者异构体的形成，并且在同一配体系统中，过氧/双氧（mu-oxo）平衡可以从一个极端转移到另一个极端。关于二氧加合物2H和3（NMe2）对外部底物的反应性的观察也被提出。
The variation of ligand para substituents on pyridyl donor groups of tridentate amine copper(I) complexes was carried out in order to probe electronic effects on the equilibrium between mu-eta2:eta2-(side-on)-peroxo [Cu(II)2(O2(2-))]2+ and bis(mu-oxo) [Cu(III)2(O(2-))2] species formed upon reaction with O2. [Cu(I)(R-PYAN)(MeCN)n]B(C6F5)4 (R-PYAN = N-[2-(4-R-pyridin-2-yl)-ethyl]-N,N',N'-trimethyl-propane-1,3-diamine, R = NMe2, OMe, H, and Cl) (1R) vary over a narrow range in their Cu(II)/Cu(I) redox potentials (E(1/2) vs Fe(cp)2(+/0) = -0.40 V for 1(NMe2), -0.38 V for 1(OMe), -0.33 V for 1H, and -0.32 V for 1Cl) and in C-O stretching frequencies of their carbonyl adducts, 1R-CO: nu(C-O) = 2080, 2086, 2088, and 2090 cm(-1) for R = NMe2, OMe, H, and Cl, respectively. However, within this range of electronic properties for 1R, dioxygen reactivity is significantly affected. The reaction of 1Cl or 1H with O2 at -78 degrees C in CH2Cl2 gives UV-vis and resonance Raman spectra indicative of a mu-eta2:eta2-(side-on)-peroxo dicopper(II) adduct (2R). Compound 1(OMe) reacts with O2, yielding equilibrium mixtures of side-on peroxo (2(OMe)) and bis(mu-oxo) (3(OMe)) species. Oxygenation of 1(NMe2) leads to the sole generation of the bis(mu-oxo) dicopper(III) complex (3(NMe2)). A solvent effect was also observed; in acetone or THF, increased ratios of bis(mu-oxo) relative to side-on peroxo complex are observed. Thus, the equilibrium between a dicopper side-on peroxo and bis(mu-oxo) species can be tuned by ligand design-specifically, more electron donating ligands favor the formation of the latter isomer, and the peroxo/bis(mu-oxo) equilibrium can be shifted from one extreme to the other within the same ligand system. Observations concerning the reactivity of the dioxygen adducts 2H and 3(NMe2) toward external substrates are also presented.