Low-Valent Metal Ions as MOF Pillars: A New Route Toward Stable and Multifunctional MOFs
Low-Valent Metal Ions as MOF Pillars: A New Route Toward Stable and Multifunctional MOFs
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DOI：
10.1021/jacs.1c05564
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发表时间：
2021-08-19
影响因子：
15
通讯作者：
Humphrey, Simon M.
中科院分区：
文献类型：
--
作者：
Sikma, R. Eric;Katyal, Naman;Humphrey, Simon M.
PCM-102 是一种新型有机膦金属有机框架 (MOF)，具有由一对偏置反式 P(III) 供体组成的二膦袋。合成后将 M(I) 盐（M = Cu、Ag、Au）添加到 PCM-102 中会诱导单晶到单晶的转变，并形成反式-[P2M](+) 固态复合物（其中 P = 基于骨架的三芳基膦）。虽然未金属化的 PCM-102 孔隙率较低，但添加二级路易斯酸来安装刚性 P-M-P 柱可显着提高稳定性和选择性气体吸收性能，N-2 Brunauer-Emmett-Teller 表面积 >1500 m(2) g(-1)。 Ag(I) 类似物也可以通过简单的一锅法围合成路线获得，并且是通过后合成、溶剂辅助金属交换混合双金属 M-A/M-B 柱材料的理想牺牲前体。值得注意的是，与传统的类似分子复合物不同，M-PCM-102 MOF 系列包含不含抗衡阴离子的周期性反式-[P2M](+) 位点，因为前体 PCM-102 MOF 是单阴离子的，能够获得电荷中性的金属柱材料。对四种 M-PCM-102 材料的 C2 烃分离进行了评估。发现分离性能可根据掺入的金属进行调节，并采用密度泛函理论来阐明所观察到的不寻常吸附偏好的本质：C2H2 > C2H6 > C2H4。
PCM-102 is a new organophosphine metal-organic framework (MOF) featuring diphosphine pockets that consist of pairs of offset trans-oriented P(III) donors. Postsynthetic addition of M(I) salts (M = Cu, Ag, Au) to PCM-102 induces single-crystal to single-crystal transformations and the formation of trans-[P2M](+) solid-state complexes (where P = framework-based triarylphosphines). While the unmetalated PCM-102 has low porosity, the addition of secondary Lewis acids to install rigid P-M-P pillars is shown to dramatically increase both stability and selective gas uptake properties, with N-2 Brunauer-Emmett-Teller surface areas >1500 m(2) g(-1). The Ag(I) analogue can also be obtained via a simple, one-pot peri-synthetic route and is an ideal sacrificial precursor for materials with mixed bimetallic M-A/M-B pillars via postsynthetic, solvent-assisted metal exchange. Notably, the M-PCM-102 family of MOFs contain periodic trans-[P2M](+) sites that are free of counter anions, unlike traditional analogous molecular complexes, since the precursor PCM-102 MOF is monoanionic, enabling access to charge-neutral metal-pillared materials. Four M-PCM-102 materials were evaluated for the separation of C2 hydrocarbons. The separation performance was found to be tunable based on the metal(s) incorporated, and density functional theory was employed to elucidate the nature of the unusual observed sorption preference, C2H2 > C2H6 > C2H4.