Complexation, Structure, and Superoxide Dismutase Activity of the Imidazolate-Bridged Dinuclear Copper Moiety with -C
详细信息 查看全文
- 作者：Heng Fu ; Ying-Hua Zhou ; Wei-Lin Chen ; Zhuo-Ga Deqing ; Ming-Liang Tong ; Liang-Nian Ji ; and Zong-Wan Mao
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：April 19, 2006
- 年：2006
- 卷：128
- 期：15
- 页码：4924 - 4925
- 全文大小：82K
- 年卷期：v.128,no.15(April 19, 2006)
- ISSN：1520-5126
文摘
An imidazolate-bridged homodinuclear complex, {[Cu(L)(H2O)]2(im)}(ClO4)3 (1), assembled with 
-cyclodextrin (CD) and its guanidinium-containing derivative (GCD), and thus a helical inclusion complex, {[Cu(L)(H2O)(CD)]2(im)}(ClO4)3 (2), were successfully isolated and structurally characterized. Structural analysis showed that each Cu(II) ion has a distorted square pyramidal N4Ow coordination sphere and forms a chiral chain through hydrogen-bonding and hydrophobic interactions. The UV-vis data showed that such a chain can provide the imidazolate bridge additional stability and results in the dissociation equilibrium taking place at the physiological pH. The obtained IC50 value for 2 (0.23 
M) showed a high superoxide dismutase (SOD) activity, which corresponds to a highly stable imidazolate bridge. Interestingly, the guanidinium-containing 1/GCD system showed higher SOD activity (IC50 = 0.16 M), which is enhanced at least by 30% in comparison with that of guanidinium-lacking 2. This result supports that the positive guanidinium plays a role in the catalytic mechanism of Cu,Zn-SOD by ensuring that superoxide enters and peroxide leaves rapidly from the coordination sphere of the copper ion.
-cyclodextrin (CD) and its guanidinium-containing derivative (GCD), and thus a helical inclusion complex, {[Cu(L)(H2O)(CD)]2(im)}(ClO4)3 (2), were successfully isolated and structurally characterized. Structural analysis showed that each Cu(II) ion has a distorted square pyramidal N4Ow coordination sphere and forms a chiral chain through hydrogen-bonding and hydrophobic interactions. The UV-vis data showed that such a chain can provide the imidazolate bridge additional stability and results in the dissociation equilibrium taking place at the physiological pH. The obtained IC50 value for 2 (0.23 M) showed a high superoxide dismutase (SOD) activity, which corresponds to a highly stable imidazolate bridge. Interestingly, the guanidinium-containing 1/GCD system showed higher SOD activity (IC50 = 0.16 M), which is enhanced at least by 30% in comparison with that of guanidinium-lacking 2. This result supports that the positive guanidinium plays a role in the catalytic mechanism of Cu,Zn-SOD by ensuring that superoxide enters and peroxide leaves rapidly from the coordination sphere of the copper ion.