摘要
两种Ｎ，Ｎ，Ｎ＇，Ｎ＇－四（２＇－苯并咪唑甲基）－１，４－二乙氨基乙二醚（ＥＧＴＢ）铜（Ｉ）双核配合物［Ｃｕ＿２（ＥＧＴＢ］Ｘ＿２（Ｘ＝Ｃｌ￣－ＢＦ￣－＿４）已合成．电子光谱和荧光发射谱表明它们可与分子氧结合，氧合－脱氧循环可重复多次；ＣＶ法测得配合物氧化还原电势，表明ＣＵ（Ⅱ）配合物（氧化型）有超氧化物歧化酶（ＳＯＤ）活性，定性检测还表明氧化型有过氧化氢酶（ＣＡＴ）性质，能分解Ｈ＿２Ｏ＿２放出Ｏ＿２气．首次发现和证明了同一配体不同氧化态配合物分别具有载氧、ＳＯＤ及ＣＡＴ活性．
Two binuclear Cu(I ) complexes of the ligand N,N,N',N'-tetrakis (2'-benzimidazolyl methyl)-1, 4-diethylene amino glycol ether (EGTB) have been made. The complexes have a general formula [Cu(EGTB)]X2(X=Cl￣- or BF￣-_4). Itis found that the complexes can slowly bind with oxygen bubbling O_2. The initial dioxygen adduct of [Cu_2 (EGTB)O_2]￣2+ in a dimethyl formamide (DMF) solution gives new electronic absorption peaks at 305, 440 and 735 nm. The fluorescence emission intensity of [Cu_2 (EGTB)]￣2+at 345 nm (excitation at 299nm) decreases rapidly with bubbling O_2 or on exposure to air and then increases adding ascrbic acid (AA). The oxy- and deoxy-cycles can repeated several times. The dioxygen compexes show a strong quencher of fluorescence with respect to that of unoxygenated species. The Cu(I ) complexes do not show a significant ESR signal, but the ESR spectra of dioxygen adducts in frozen DMF solution show a typical axially symmetric triplet spectrum with g∥>g⊥ and g∥<2. 3, which imply that the unpaired electron of copper(Ⅱ) resides in d_x2-y2 orbital and the coordination bonds possess considerable covalent character. The half-field signals (△ms=2) at ca 1500 G (1G= 10￣-4 T) is also clearly seen, which suggests that there is an anti-ferromagnetic coupling between the copper(Ⅱ) ions. Cyclic voltammetry (CV) measurements indicate that the redox potential of the complexes intermidiate between-0. 45 and +0. 98 V, which suggests that the oxidized complexes possess an activity of superoxide dismutase(SOD). In oxygen there is a stable, well-formed, reversible cyclic voltammograms in DMF at a glassy carbon electrode for O2/O2 couple. Adding aoxidized complex, so that the cathodic peak current for the reduction of O2 increases and the anodic peak corresponding to the oxidation of O disappears. Morever,their oxidized forms are both capable of promoting decomposition of hydrogen peroxide. It is evident for the first time that various oxidation state complexes consist of the same metal ion with the sam
出处
《华中师范大学学报（自然科学版）》
CAS
CSCD
1994年第2期201-206,共6页
Journal of Central China Normal University：Natural Sciences
基金
湖北省自然科学基金
关键词
二氧络合物
双核络合物
铜
EGTB
binuclear Cu(I) complex
dioxygen complex
model compound
