Vectorial Catalysis in Surface-Anchored Nanometer-Sized Metal-Organic Frameworks-Based Microfluidic Devices

Solvent-Regulated Formation of Metal/Metal-Oxo Nodes in Two Indium Metal-Organic Frameworks: Syntheses, Structures, Selective Gas Adsorption and Fluorescence Sensor Properties

Two water-stable indium metal-organic frameworks, (NH2Me2)3[In3(BTB)4] ⋅ 12DMA ⋅ 4.5H2O (In-MOF-1) and (NH2Me2)9[In9O6(BTB)8(H2O)4(DMSO)4] ⋅ 27DMSO ⋅ 21H2O (In-MOF-2) (BTB=4,4',4''-benzene-1,3,5-tribenzoate) with 3D interpenetrated structure has been constructed by regulating solvents. Structure analysis revealed that In-MOF-1 has a three-dimensional (3D) structure with a single metal core, while In-MOF-2 features an octahedron cage constructed by three kinds of metal clusters to further form a 3D structure. The fluorescence investigations showed that In-MOF-1 and In-MOF-2 are potential MOF-based fluorescent sensors to detect acetone and Fe3+ ions in EtOH or water with high sensitivity, excellent selectivity, recyclability and a low limit of detection. Moreover, the fluorescence mechanisms of In-MOF-1 and In-MOF-2 toward acetone and Fe3+ ions were further explained. In addition, In-MOF-2 has higher thermal and framework stability than In-MOF-1. The activated In-MOF-2 presents a high BET surface area of 998.82 m2g-1 and a pore size distribution of 8 to 16 Å. At the same time, In-MOF-2 exhibits high selective CO2 adsorption for CO2/CH4 and CO2/N2, respectively. Furthermore, the adsorption sites and adsorption isotherms were predicted using grand canonical Monte Carlo (GCMC) simulations, and the adsorption energy of the lowest-energy adsorption configuration was calculated using molecular dynamics (MD) simulations.

Sequential Assembly and Stabilization of Cu6S6 Octahedral Clusters in NaCl-, NiAs-, and CdI2-Related Structures and Their Utility toward Thermochromism and Multicomponent Hantzsch Reaction

Seven new inorganic-organic coordination polymer compounds have been synthesized and their structures are determined by single-crystal structure determination. The compounds were prepared by the sequential assembly of a [Cu₆(mna)₆]^6- moiety in the presence of a Mn salt and a secondary amine ligand. Of the seven compounds, [{Cu₆(mna)₆}Mn₃(H₂O)(H₂O)_1.5]·5.5H₂O (I), [{Cu₆(mna)₆}Mn₃(H₂O)(Im)_1.5]·3.5H₂O (Ia), [{Cu₆(mna)₆}{Mn(BPY)(H₂O)}₂{Mn(H₂O)₄}]·2H₂O (III), and [{Cu₆(mna)₆}{Mn(BPE)_0.5(H₂O)₂}₂{Mn(BPE)(H₂O)₂}] (IV) have a three-dimensional structure, whereas [{Cu₆(mna)_4.5(Hmna)_1.5}{Mn(BPA)(H₂O)₂}{Mn(H₂O)}]{Mn_0.25(H₂O)₃}·7H₂O (II), [{Cu₆(mna)₆}{Mn(4-BPDB)_0.5H₂O}{Mn(H₂O)₂}].{Mn(H₂O)₆}·6H₂O (V), and [{Cu₆(mna)₄(Hmna)₂}·{Mn(H₂O)₃}₂]·(4-APY)₂·6H₂O (VI) have a two-dimensional structure. Some of the prepared compounds exhibit structures that closely resemble the classical inorganic structures, such as NaCl (Ia, III), NiAs (I), and CdI₂ (IV and VI). The stabilization of such simple structures from the assembly of octahedral Cu₆S₆ clusters and different Mn species and aromatic nitrogen-containing ligands suggests the subtle interplay between the constituent reactants. The compounds were examined for the multicomponent Hantzsch reaction, which gave the product in good yields. The compounds, II and VI, on heating to 70 °C change color reversibly from pale yellow to deep red, which suggests the possible use of these compounds as thermochromic materials. The present study suggests that the Cu₆S₆ octahedral clusters can be assembled into structures that resemble classical inorganic structures.

Metal Node Control of Brønsted Acidity in Heterobimetallic Titanium-Organic Frameworks

Compared to indirect framework modification, synthetic control of cluster composition can be used to gain direct access to catalytic activities exclusive of specific metal combinations. We demonstrate this concept by testing the aminolysis of epoxides with a family of isostructural mesoporous frameworks featuring five combinations of homometallic and heterobimetallic metal-oxo trimers (Fe3, Ti3, TiFe2, TiCo2, and TiNi2). Only TiFe2 nodes display activities comparable to benchmark catalysts based on grafting of strong acids, which here originate from the combination of Lewis Ti4+ and Brønsted Fe3+-OH acid sites. The applicability of MUV-101(Fe) to the synthesis of β-amino alcohols is demonstrated with a scope that also includes the gram scale synthesis of propranolol, a natural β-blocker listed as an essential medicine by the World Health Organization, with excellent yield and selectivity.