Self-Assembly of Catalytically Active Supramolecular Coordination Compounds within Metal–Organic Frameworks

Supramolecular
coordination compounds (SCCs) represent the power
of coordination chemistry methodologies to self-assemble discrete
architectures with targeted properties. SCCs are generally synthesized
in solution, with isolated fully coordinated metal atoms as structural
nodes, thus severely limited as metal-based catalysts. Metal–organic
frameworks (MOFs) show unique features to act as chemical nanoreactors
for the in situ synthesis and stabilization of otherwise
not accessible functional species. Here, we present the self-assembly
of PdII SCCs within the confined space of a pre-formed
MOF (SCCs@MOF) and its post-assembly metalation to give a PdII–AuIII supramolecular assembly, crystallography
underpinned. These SCCs@MOFs catalyze the coupling of boronic acids
and/or alkynes, representative multi-site metal-catalyzed reactions
in which traditional SCCs tend to decompose, and retain their structural
integrity as a consequence of the synergetic hybridization between
SCCs and MOFs. These results open new avenues in both the synthesis
of novel SCCs and their use in heterogeneous metal-based supramolecular
catalysis.

超分子配位化合物（Supramolecular Coordination Compounds, SCCs）彰显了配位化学方法自组装获得具备目标性能离散结构的强大能力。此类化合物通常在溶液中合成，以完全配位的金属原子作为结构节点，因此作为金属基催化剂时存在严重局限。金属有机框架（Metal-Organic Frameworks, MOFs）则具备独特优势，可作为化学纳米反应器，用于原位合成并稳定难以直接获取的功能性物种。本文报道了在预合成MOF的受限空间内自组装钯(II)超分子配位化合物（即SCCs@MOF），并通过组装后金属化得到钯(II)-金(III)超分子组装体，该过程得到晶体学手段的佐证。此类SCCs@MOF可催化硼酸与/或炔烃的偶联反应——这是典型的多位点金属催化反应，传统SCCs在此类反应中易发生分解，而本体系因SCCs与MOFs的协同杂化效应，能够保持结构完整性。本研究成果为新型SCCs的合成及其在多相金属基超分子催化领域的应用开辟了全新路径。