Kinetic studies of thermal dissociation of carbon monoxide ligands from manganese tri- and tetra-carbonyl derivatives containing the bulky dipiperidylmethane ligand, CH2Pip2
Kinetic studies of thermal dissociation of carbon monoxide ligands from manganese tri- and tetra-carbonyl derivatives containing the bulky dipiperidylmethane ligand, CH2Pip2
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DOI：
10.1016/j.ica.2018.09.004
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发表时间：
2019
影响因子：
2.8
通讯作者：
T. M. Folsom;D. Darensbourg
中科院分区：
文献类型：
--
作者：
T. M. Folsom;D. Darensbourg
通过[MBr（CO）5]与CH 2 Pip 2反应，合成了7族三羰基配合物fac-[MBr（CO）3（CH 2 Pip 2）]（CH 2 Pip 2 =二哌啶甲烷，M = Mn（1），M = Re（2））.在CO存在下，配合物1与AgBF_4反应生成稳定的阳离子四羰基锰配合物[Mn（CO）_4（CH_2Pip_2）][BF_4]（3）。配合物3在乙腈中解离CO，生成溶剂合物[Mn（CH 3CN）（CO）3（CH 2 Pip 2）][BF 4]，25 °C时的速率常数为10.6 × 10−4s− 1。在水/二氯甲烷中CO从络合物3解离后，提供类似的H2O溶剂化络合物。一个额外的CO配体的损失发生在一个较慢的时间尺度上，揭示了进一步的CO交换与13 CO。与其他类似物衍生物如[Mn（CO）4（phen）]+相比，[Mn（CO）4（CH 2 Pip 2）]+阳离子中CO的损失增加，这归因于空间位阻CH 2 Pip 2配体，其削弱了Mn单键CO键的解离。
The group 7 tricarbonyl complexes,fac-[MBr(CO)3(CH2Pip2)] (CH2Pip2= dipiperidylmethane, M = Mn (1), and M = Re (2)), have been synthesized from the reaction of [MBr(CO)5] and the bulky CH2Pip2ligand. Complex1was found to react with AgBF4in the presence of carbon monoxide to provide a stable cationic manganese tetracarbonyl complex [Mn(CO)4(CH2Pip2)][BF4] (3). Complex3was shown to dissociate CO in acetonitrile to provide the solvate, [Mn(CH3CN)(CO)3(CH2Pip2)][BF4], with a rate constant of 10.6 × 10−4s−1at 25 °C. A similar H2O solvated complex was provided upon CO dissociation from complex3in water/dichloromethane. Loss of an additional CO ligand occurs on a slower timescale as revealed by further CO exchange with13CO. This enhanced loss of CO in the [Mn(CO)4(CH2Pip2)]+cation compared to other analog derivatives such as [Mn(CO)4(phen)]+is ascribed to the sterically encumbering CH2Pip2ligand which weakens the Mnsingle bondCO bond towards dissociation.