Comparative Kinetics of Oxo Transfer to Substrate Mediated by Bis(dithiolene)dioxomolybdenum and -tungsten Complexes
Comparative Kinetics of Oxo Transfer to Substrate Mediated by Bis(dithiolene)dioxomolybdenum and -tungsten Complexes
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双(二硫醇)二氧代钼和钨配合物介导的羰基转移至底物的比较动力学
DOI：
10.1021/ic971426q
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发表时间：
1998
影响因子：
4.6
通讯作者：
R. H. Holm
中科院分区：
文献类型：
--
作者：
G. Tucci;A. Donahue;R. H. Holm
最近发现的酶含有钨创造了一个新的当务之急，检查的关键特征的结构和反应性的生物相关化合物的这种元素和它们的关系，相应的性质类似的钼络合物。本文研究了[MO_2（mnt）_2]_2 ~（2-）+（RO）_3-nR'nPO → [MO（mnt）_2]_2 ~（2-）+（RO）_3-nR'nPO在DMF溶液中（M = Mo，W; n = 0，R = Me; n = 1，R = Me，R' = Ph; n = 1，R = Et，R' = Me）的二级反应中氧原子（氧代）向底物的相对转移速率。在所有温度下，kMo > kW;在298 K时，kMo/kW为102−103。以（MeO）2 PhP为底物，M = Mo/W的活化参数为ΔH_∞ = 8.2/11 kcal/mol，ΔS_∞ = −33/−38 eu.对于（MeO）3 P，其值为ΔH = 10/14 kcal/mol和ΔS = −32/−33 eu。速率差的产生主要是因为活化焓差ΔH <$W − ΔH <$Mo <$3 −4 kcal/mol。使用最近的理论处理的氘介导的氧代转移到底物（Pietsch，M.一、霍尔，M. B.
The recent discovery of enzymes containing tungsten has created a new imperative for examination of key features of the structure and reactivity of biologically related compounds of this element and their relation to the corresponding properties of analogous molybdenum complexes. We have examined the relative rates of oxygen atom (oxo) transfer to substrate in the second-order reactions [MO2(mnt)2]2- + (RO)3-nR‘nP → [MO(mnt)2]2- + (RO)3-nR‘nPO in DMF solution (M = Mo, W; n = 0, R = Me; n = 1, R = Me, R‘ = Ph; n = 1, R = Et, R‘ = Me). At all temperatures examined, kMo > kW; at 298 K, kMo/kW ≈ 102−103. For (MeO)2PhP as substrate, the activation parameters for M = Mo/W are ΔH⧧ = 8.2/11 kcal/mol and ΔS⧧ = −33/−38 eu. For (MeO)3P, the values are ΔH⧧ = 10/14 kcal/mol and ΔS⧧ = −32/−33 eu. The rate differences arise primarily because of the activation enthalpy differences ΔH⧧W − ΔH⧧Mo ≈3−4 kcal/mol. Using a recent theoretical treatment of molybdenum-mediated oxo transfer to substrate (Pietsch, M. A.; Hall, M. B....