Due to the high electron charge, large ion radius, and plentiful outer hybrid orbitals of Ln III cations, microporous Ln-MOFs can be used as Lewis acidic catalysts with high catalytic activity for a variety of organic reactions, which prompts us to explore cluster-based nanoporous Ln-MOFs by employing structure-oriented ligands. Herein, the exquisite combination of coplanar [Ln 4 (μ 3 −OH) 2 (μ 2 −HCO 2 )(H 2 O) 2 ] clusters (abbreviated as {Ln 4 }) and the structure-oriented multifunctional ligand ofTo the best of our knowledge, NUC-38Ho and NUC-38Yb are rarely reported {Ln 4 }-based three-dimensional (3D) frameworks with embedded hierarchical triangular-microporous and hexagonal-nanoporous channels, which are shaped by six rows of coplanar {Ln 4 } clusters and characterized by plentiful coexisting Lewis acid−base sites on the inner wall including open Ln III sites, N pyridine atoms, μ 3 −OH, and μ 2 −HCO 2 . Catalytic experiments performed using NUC-38Yb as the representative exhibited that NUC-38Yb possessed a high catalytic activity on the cycloaddition reactions of epoxides with CO 2 under mild conditions, which can be ascribed to its structural advantages including nanoscale channels, rich bifunctional active sites, large surface areas, and chemical stability. Moreover, NUC-38Yb, as a heterogeneous catalyst, could greatly accelerate the Knoevenagel condensation reactions of aldehydes and malononitrile. Hence, this work paves the way for the construction of functional Ln-cluster-based nanoporous metal−organic frameworks (MOFs) by elaborately designing functional ligands with transnormal connection modes.

In terms of ligand-directed synthetic strategy, multifunctional metal−organic frameworks (MOFs) could be assembled by employing organic ligands with nitrogen-containing heterocycles, which could serve as Lewis base sites in crystallized porous frameworks. Here, the acidic one-pot hydrothermal reaction of CaCl 2 , Zn(NO 3 ) 2 , and 2,4,6-tri(2,4-dicarboxyphenyl)pyridine (H 6 TDP) generates one robust honeycomb-shaped double-walled), which has the excellent physicochemical characteristics of nanoscopic channels, high porosity (58.3%), large specific surface area, and high heat/water-resisting property. To the best of our knowledge, this is the first 3s−3d dinuclear [CaZn(CO 2 ) 6 (OH 2 )]based nanoporous host framework, whose activated state possesses the coexistence of Lewis acid−base sites including four-coordinated Zn 2+ ions, four-coordinated Ca 2+ ions, uncoordinated carboxyl oxygen atoms, and N pyridine atoms. As expected, because of the coexistence of Lewis acid−base nature, desolvated NUC-21 displays satisfactory catalytic activity on the chemical cycloaddition of various epoxides with CO 2 into the corresponding alkyl carbonates under comparatively mild conditions. Furthermore, the efficient conversion of benzaldehydes and malononitrile confirms that NUC-21 is simultaneously a bifunctional heterogeneous catalyst for Knoevenagel condensation reactions. Hence, the achievements broaden the way for assembling nanoporous multifunctional MOFs by employing ligand-directed synthetic strategy, which can accelerate the transformation from simple structural research to socially demanding applications.

Stable metal–organic frameworks containing periodically arranged nanosized pores and active Lewis acid–base active sites are considered as ideal candidates for efficient heterogeneous catalysis. Herein, the exquisite combination of [Y2(CO2)7(H2O)2] cluster (abbreviated as {Y2}) and multifunctional linker of 2,4,6-tri­(2,4-dicarboxyphenyl)­pyridine (H6TDP) led to a nanoporous framework of {[Y2(TDP)­(H2O)2]·5H2O·4DMF} n (NUC-53, NUC = North University of China), which is a rarely reported binuclear three-dimensional (3D) framework with hierarchical tetragonal-microporous (0.78 nm) and octagonal-nanoporous (1.75 nm) channels. The inner walls of these channels are aligned by {Y2} clusters and plentifully coexisted Lewis acid–base sites of YIII ions and Npyridine atoms. Furthermore, NUC-53 has a quite large void volume of ∼65.2%, which is significantly higher than most documented 3D rare-earth-based MOFs. The performed catalytic experiments exhibited that activated NUC-53 showed a high catalytic activity on the cycloaddition reactions of CO2 with styrene oxide under mild conditions with excellent turnover number (TON: 1980) and turnover frequency (TOF: 495 h–1). Moreover, the deacetalization–Knoevenagel condensation reactions of benzaldehyde dimethyl acetal and malononitrile could be efficiently prompted by the heterogeneous catalyst of NUC-53. These findings not only pave the way for the construction of nanoporous MOF based on rare-earth clusters with a variety of catalytic activities but also provide some new insights into the catalytic mechanism.

Seeking strategies to enhance the chemical stability of metal−organic framework (MOF) materials has become a focus for practical applications, which prompts us to carry out the exploratory self-assembly of microporous heterometallic MOFs by introducing alkali metal ions. Herein, the exquisite combination of scarcely reported S-shaped [Pb 10 K 2 (μ 2 -OH) 2 (COO) 24 ] clusters and 2,4,6tri(2,4-dicarboxyphenyl)pyridine (H 6 TDP) ligands under solvothermal conditions generated a highly robust microporous framework ofopen channels along the a-axis. Thanks to the excellent confined pore environments, such as large surface area, rich Lewis acid sites including Pb 2+ and K + , plentiful Lewis base sites including the μ 2 -OH group and N pyridine atom, and open channels, activated NUC-45a exhibits excellent catalytic performance in the cycloaddition of CO 2 with various epoxides under mild conditions. Moreover, NUC-45a, as a heterogeneous catalyst, shows a high catalytic activity for Knoevenagel condensation of aldehydes and malononitrile with high catalytic stability and recyclability. Meanwhile, both reactions have a high turnover number and turnover frequency. This work shows that the use of multifunctional organic ligands and the introduction of alkali metal ions are conducive to the construction of porous cluster-based metal−organic materials with excellent heterogeneous catalysis.

The exquisite combination of hetreometallic [TbIIINiII(COO)3(H2O)] clusters with a designed hexatopic ligand generates one highly robust three-dimensional heterometallic TbIII/NiII–organic framework material.

The high catalytic activity of metal–organic frameworks (MOFs) can be realized by increasing their effective active sites, which prompts us to perform the functionalization on selected linkers by introducing a strong Lewis basic group of fluorine. Herein, the exquisite combination of paddle-wheel [Cu2(CO2)4(H2O)] clusters and meticulously designed fluorine-funtionalized tetratopic 2′,3′-difluoro-[p-terphenyl]-3,3″,5,5″-tetracarboxylic acid (F-H4ptta) engenders one peculiar nanocaged {Cu2}-organic framework of {[Cu2(F-ptta)­(H2O)2]·5DMF·2H2O} n (NUC-54), which features two types of nanocaged voids (9.8 Å × 17.2 Å and 10.1 Å × 12.4 Å) shaped by 12 paddle-wheel [Cu2(COO)4H2O)2] secondary building units, leaving a calculated solvent-accessible void volume of 60.6%. Because of the introduction of plentifully Lewis base sites of fluorine groups, activated NUC-54a exhibits excellent catalytic performance on the cycloaddition reaction of CO2 with various epoxides under mild conditions. Moreover, to expand the catalytic scope, the deacetalization-Knoevenagel condensation reactions of benzaldehyde dimethyl acetal and malononitrile were performed using the heterogenous catalyst of NUC-54a. Also, NUC-54a features high recyclability and catalytic stability with excellent catalytic performance in subsequent catalytic tests. Therefore, this work not only puts forward a new solution for developing high-efficiency heterogeneous catalysts, but also enriches the functionalization strategies for nanoporous MOFs.

The exquisite combination of independent 3p [In­(CO2)4] units and 4f [Tb2(CO2)8] clusters in the presence of the designed hexatopic 2,4,6-tri­(2,4-dicarboxyphenyl)­pyridine ligand engenders one peculiar nanocaged In­(III)­{Tb­(III)}2-organic framework: ({(Me2NH2)­[InTb2(HTDP)2]·3DMF·3H2O}n, designated as NUC-5), which features dual types of lotus-shaped channels along the [100] and [110] axes with related node windows of 5.3 × 6.8 and 12.1 × 9.2 Å2, respectively. To the best of our knowledge, except several coexisted 3p-4f In/Ln clusters of {In3Ln}- and {In3Ln2}-based metal–organic frameworks (MOFs), NUC-5 is one novel type of In/Ln heterometallic framework. In addition, its topology was an unprecedented 3D TAYZIC net with a Schläfli symbol of {4.462}­{4.565}2{4.66.88}. Moreover, activated NUC-5 is proved to be one efficient adsorbent for CO2 and one recycled cycloaddition catalyst for the transformation of epoxides into related carbonates with high yields under mild conditions. Furthermore, the excellent reversible sorption performance for I2 in the volatilization phase or in cyclohexane solution with a maximum adsorption capacity of 609.1 mg/g (3.75 iodine molecules per unit cell) makes NUC-5 a promising adsorbent for radioactive products of 129I and 131I in the field of nuclear industry. This study provides one synthetic strategy that the original nature of MOFs could be enhanced by introducing some specific function-prompted inorganic subunits with the aid of predesigned supporting ligands.

The exquisite combination of Ba 2+ and Zn 2+ with the aid of 2,4,6tri(2,4-dicarboxyphenyl)pyridine (H 6 TDP) under the condition of solvothermal selfassembly generates one highly robust [Ba 3 Zn 4 (CO 2 ) 12 (HCO 2 ) 2 (OH 2 ) 2 ]−organic framework of {[Ba 3 Zn 4 (TDP) 2 (HCO 2 ) 2 (OH 2 ) 2 ]•7DMF•4H 2 O} n (NUC-27), in which adjacent 2D layers are interlaced via hydrogen-bonding interactions to form a 3D skeleton with peapod-like channels and nano-caged voids. It is worth emphasizing that both Ba 2+ and Zn 2+ ions in NUC-27 display the extremely low coordination modes: hexa-coordinated [Ba(1)] and tetra-coordinated [Ba(2), Zn(1), and Zn(2)]. Furthermore, to the best our knowledge, NUC-27 is one scarcely reported 2Dbased nanomaterial with an unprecedented Z-shaped hepta-nuclear heterometallic cluster of [Ba 3 Zn 4 (CO 2 ) 12 (HCO 2 ) 2 (OH 2 ) 2 ] as SBUs, which not only has plentiful low-coordinated open metal sites but also has the excellent physicochemical properties including omni-directional opening pores, ultrahigh porosity, larger specific surface area, and the coexistence of Lewis acid-base sites. Just as expected, thanks to its rich active metal sites and pyridine groups as strong Lewis acid-base roles, completely activated NUC-27 displays high catalytic efficiency on the chemical transformation of epoxides with CO 2 into cyclic carbonates under mild conditions and effectively accelerates the reaction process of Knoevenagel condensation.