Multiple Coordination Exchanges for Room-Temperature Activation of Open-Metal Sites in Metal-Organic Frameworks
Multiple Coordination Exchanges for Room-Temperature Activation of Open-Metal Sites in Metal-Organic Frameworks
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DOI：
10.1021/acsami.7b07299
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发表时间：
2017-07-26
影响因子：
9.5
通讯作者：
Jeong, Nak Cheon
中科院分区：
文献类型：
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作者：
Bae, Jinhee;Choi, Jae Sun;Jeong, Nak Cheon
金属有机骨架(MOF)中开放配位中心(OCs)的活化，即去除OCs上配位的溶剂分子，是金属有机骨架在气体化学吸附、分离和催化等潜在应用中所需的关键步骤，因为OCs通常在这些应用中起关键作用。最近，我们开发了一种在室温下进行二氯甲烷(DCM)处理的化学活化方法，该方法被认为是一种很有前途的替代传统热活化(TA)的方法，因为它不需要施加外部热能，从而保持了MOF的结构完整性。然而，仅用DCM处理很难去除N，N-二甲基甲酰胺(DMF)、N，N-二乙基甲酰胺(DEF)和二甲基亚砜(DMSO)等强配位溶剂。在这份报告中，我们展示了一个多配位交换(CE)过程，最初与乙腈(MeCN)、甲醇(MeOH)或乙醇(Etoh)执行，然后与DCM一起执行，以实现具有较强抽提作用的OCS的完全激活。因此，这一过程可以作为一种在室温下不需要加热的有效的“化学途径”来激活，据我们所知，以前没有研究证明使用这种多CE过程来激活OCS，尽管在TA过程之前的前处理步骤中普遍使用了MeOH和/或DCM。使用MOF-74(Ni)，我们证明了这种多重CE过程可以安全地激活热不稳定的MOF，而不会造成结构破坏。此外，在原位H-1核磁共振和拉曼光谱研究的基础上，我们对多个CE的活化行为提出了一个合理的机理。
The activation of open coordination sites (OCSs) in metal organic frameworks (MOFs), i.e., the removal of solvent molecules coordinated at the OCSs, is an essential step that is required prior to the use of MOFs in potential applications such as gas chemisorption; separation, and catalysis because OCSs often Serve as key sites in these applications. Recently, we developed a "chemical activation" method involving dichloromethane (DCM) treatment at room temperature, which is considered to be a promising alternative to conventional thermal activation (TA), because it does not require the application of external thermal energy, thereby preserving the structural integrity of the MOFs. However, strongly coordinating solvents such as N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF), and dimethyl sulfoxide (DMSO) are difficult to remove solely with the DCM treatment. In this report, we demonstriate a multiple coordination exchange (CE) process executed initially with acetonitrile (MeCN), methanol (MeOH), or ethanol (EtOH) and subsequently with DCM to achieve the complete activation of OCSs that possess strong extracoordination. Thus, this process can serve as an effective "chemical route" to activation at room temperature that does not require applying heat, To the best of our knowledge, no previous study has demonstrated the activation of OCSs using this multiple CE process, although MeOH and/or DCM has been popularly used in pretreatment steps prior to the TA process. Using MOF-74(Ni), we demonstrate that this multiple CE process can safely activate a thermally unstable MOF without inflicting structural damage. Furthermore, on the basis of in situ H-1 nuclear magnetic resonance (1H NMR) and Raman studies, we propose a plausible mechanism for the activation behavior of multiple CE.