COPPER-MEDIATED HYDROXYLATION OF AN ARENE - KINETICS AND MECHANISM OF THE REACTION OF A DICOPPER(II) META-XYLYL-CONTAINING COMPLEX WITH H2O2 TO YIELD A PHENOXODICOPPER(II) COMPLEX
COPPER-MEDIATED HYDROXYLATION OF AN ARENE - KINETICS AND MECHANISM OF THE REACTION OF A DICOPPER(II) META-XYLYL-CONTAINING COMPLEX WITH H2O2 TO YIELD A PHENOXODICOPPER(II) COMPLEX
复制标题
DOI：
10.1021/ja00223a020
复制
发表时间：
1988-07-20
影响因子：
15
通讯作者：
KARLIN, KD
中科院分区：
文献类型：
--
作者：
CRUSE, RW;KADERLI, S;KARLIN, KD
报道了H2 O2将双铜（II）配合物{Cu 2（L-H）}4+（5）羟基化生成苯氧和羟基双桥{Cu 2（L-O）（OH）}2+（3）的动力学和机理。在50%H_2O/N，N-二甲基甲酰胺体系中，反应为二级络合物反应，H_2O_2为一级反应，[H+]为一级反应。完全速率定律由v = k[{Cu 2（L-H）}4+]2[H2 O2]/（[H+]（1 + K[{Cu 2（L-H）}4+]））给出，其中k = 0.4 M-1 s-1且K = 4500 M-1。用{Cu 2（L-D）}4+代替Cu 2（L-H）}4+不存在氘效应消除了作为限速步骤的夺氢，并指出了反应性且可能亲电的羟基化剂的攻击。配合物5中的二级依赖性和pH依赖性通过氢过氧化物中间体{Cu 2（L-H）（OOH）}3+（6）的形成来解释。该中间体随后在第二分子5的影响下转化为3，所述第二分子5充当刘易斯酸并促进氢过氧化物络合物中的O/O键断裂。
The kinetics and mechanism of the hydroxylation by H2O2 of a dicopper (II) compex {Cu2(L-H)}4+ (5) to the phenoxo and hydroxo doubly bridged produced {Cu2(L-O)(OH)}2+ (3) are reported. In 50% H2O/N,N-dimethylformamide the reaction is second order in complex, first order in H2O2, and inversely first order in [H+]. The complete rate law is given by v = k[{Cu2(L-H)}4+]2[H2O2]/([H+](1 + K[{Cu2(L-H)}4+])) where k = 0,4 M-1 s-1 and K = 4500 M-1. The absence of a deuterium effect with {Cu2(L-D)}4+ in the place of Cu2(L-H)}4+ eliminates hydrogen abstraction as the rate-limiting step and points to an attack by a reactive and probably electrophilic hydroxylating agent. The second-order dependence in complex 5 and the pH dependence are explained by the formation of a hydroperoxide intermediate, {Cu2(L-H)(OOH)}3+ (6). the intermediate is subsequently transformed into 3 under the influence of a second molecule of 5 which acts as a Lewis acid and promotes O.sbd.O bond rupture in the hydroperoxide complex.