Cluster-based Metal-organic Frameworks Research Articles

A novel trinuclear Cd(ii) cluster-based metal–organic framework: synthesis, structure and luminescence properties

A novel luminescent Cd-MOF based on trinuclear Cd cluster and H2PZC ligand has been constructed, it may be used as a potential luminescent probe for the detection of acetone, Na+ and Fe2+.

A new class of cuprous bromide cluster-based hybrid materials: direct observation of the stepwise replacement of hydrogen bonds by coordination bonds.

Although a variety of functional metal-organic frameworks (MOFs) have been synthesized, post-modified, and applied in various areas, there is little knowledge about how molecular cluster building units are stepwise evolved into MOFs via intermediates. Coordination bonds are generally stronger than hydrogen bonds, and thus equivalent replacement of X-H···Y hydrogen bonds by X-M-Y coordination bonds can transform hydrogen bond networks into MOFs. In this work, solvothermal in situ reduction reactions of CuBr2 and 1,4-diazoniabicyclo[2,2,2]octane (DABCO) generated a myriad of tunable photoluminescent cuprous body-centered cubic bromide cluster-based networks with the general formula [Cu4+xH4-xBr6(DABCO)4](HCO2)2·S (x = 0, 0.56, 0.81, 1.27, 1.39, 2.56, 2.78, and 4 for compounds 1-8, respectively). All of these compounds crystallize in the cubic space group with the largest volume difference being only 5.2%, but they belong to three remarkably different kinds of crystals. Complex 1 is a molecular crystal and consists of tetrahedral [Cu4Br6(HDABCO)4](2+) clusters with monodentate HDABCO groups that are supported via N-H···Br synthons in the hydrogen bond network. Compound 8 is a [Cu8Br6](2+) cube cluster-based MOF with bridged DABCO ligands. Complexes 2-7 are seemingly impossible Cu/H-substituted solid solutions of 1 and 8. The CuBr framework components in 1-8 are Cu4Br6, Cu4.56Br6, Cu4.81Br6, Cu5.27Br6, Cu5.39Br6, Cu6.56Br6, Cu6.78Br6, and Cu8Br6, respectively. Crystallization kinetics studies revealed that the [Cu4Br6(HDABCO)4](2+) cluster-based hydrogen bond network (1) was initially formed such that N-H···Br hydrogen bonds could be stepwise replaced by N-Cu-Br coordination bonds to form the [Cu8Br6](2+) cube cluster-based MOF (8) via solid solutions. These observations directly reveal the equivalence and transformation between the N-H···Br hydrogen bond and the N-Cu-Br coordination bond and the evolutionary mechanism of a molecular crystal to a MOF via solid solutions, which is of fundamental importance in materials but has never before been revealed. DFT calculations suggest that equivalent replacement of a N-H···Br hydrogen bond by a N-Cu-Br coordination bond is exothermic and exergonic, which also supports the transformation from molecule 1 to MOF 8.

Construction of CuII Cluster-Based Magnetic Metal–Organic Framework Derived from a V-Shaped Aromatic Dicarboxylate Ligand

In our efforts towards rational design and systematic synthesis of cluster-based metal–organic frameworks, a new CuII coordination framework derived from the V-shaped aromatic dicarboxylate with formula [Cu4(µ4-O)(L)3]∞ (1), H2L = (4-phenyl)-2,6-bis(4-carboxyphenyl)pyridine) was synthesised under hydrothermal conditions and structurally characterised by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, and infrared spectroscopy. Structure analysis shows that complex 1 has a three-dimensional framework based on [Cu8] cluster with 8-connected bcu topology. Magnetic investigation suggests that anti-ferromagnetic coupling exists between CuII ions in the [Cu8] cluster.

Co(II) coordinated metal-organic framework: An efficient catalyst for heterogeneous aerobic olefins epoxidation

An 8-connected, linear trinuclear cluster-based microporous metal organic framework (NH4)2[Co3(Ina)(BDC)3(HCOO)] (denoted as Co3InaBDC3, Ina=isonicotinate and BDC=1,4-benzenedicarboxylate, CCDC is 935147) had been successfully synthesized by a facile hydrothermal synthesis method. The compound was extended through BDC linkers breadthwise and Ina linkers lengthways to the highly-connected framework. The Co3InaBDC3 was characterized through FT-IR, N2 adsorption, XRD, TGA and SEM, and its characteristic structure was elucidated by single crystal X-ray diffraction. Using O2 as oxidant, the Co3InaBDC3 was investigated as a good performed heterogeneous catalytic material for cyclooctene epoxidation. An extremely high turnover frequency (1370h−1) for epoxycyclooctane was achieved, and Co3InaBDC3 exhibited excellent stabilities in 5 recycles without any loss of its catalytic performance.

PH-dependent two novel 3D polynuclear cobalt(ii) cluster-based metal–organic frameworks constructed from a tri-pyridyl-bis-amide and a polycarboxylate: assembly, structures and properties

The hydrothermal reaction of CoCl2 with N,N′-bis(pyridine-3-yl)pyridine-3,5-dicarboxamide (L) and 1,3,5-benzenetricarboxylic acid (H3BTC) mixed ligands affords two novel polynuclear cobalt cluster-based metal–organic frameworks (MOFs), [Co3(L)2(BTC)2(H2O)2]·6H2O (1) and {[Co2(L)(BTC)(OH)]·2.5H2O}2 (2). Single crystal X-ray diffraction analysis reveals that the CoII ions in complex 1 are connected by BTC anions with a four-coordinated mode to form a two dimensional (2D) undulating layer based on dinuclear [Co2(COO)4] units, which is extended into a 3D (3, 4, 4, 5)-connected MOF by the L ligand with μ3-bridging coordination mode. In complex 2, the BTC ligand displays a six-coordinated mode to connect CoII ions into a 2D corrugated layer derived from tetranuclear [Co4(μ3-OH)2(COO)6] motifs, and the layers are further extended into a 3D (3, 8)-connected tfz-d MOF via μ2-bridging L ligands. The title complexes exhibit a (42·63·85)2(42·63·8)2(6·82)2(62·84) topology for 1 and a (43)2(46·618·84) topology for 2. The pH value, as well as the various coordination modes of the tri-pyridyl-bis-amide L and BTC ligands, play a crucial role in the construction of the diverse topological structures of 1 and 2. Complex 1 exhibits excellent photocatalytic activity for dye degradation under UV light. In addition, the electrochemical behaviour and magnetic and fluorescent properties of the two complexes have also been investigated.

Assembly of a unique octa-nuclear copper cluster-based metal–organic framework with highly selective CO2 adsorption over N2 and CH4

By using 4-(pyrimidin-5-yl) benzoic acid (4-PmBC) as a ligand, a porous metal-organic framework based on unique octa-nuclear copper clusters was constructed, which exhibited highly selective CO2 uptake over N2 and CH4.

A cationic copper-iodine cluster-based metal-organic framework (MOF) with (4, 8)-connected fluorite topology

Abstract A new copper-iodine based metal-organic framework compound, [Cu 3 (L)I 2 ·H 2 O] n (1) (L = 5-(4-pyridyl)tetrazole), has been synthesized by solvothermal method. X-ray analysis shows that compound 1 is a 3-D metal-organic framework constructed by the L ligands linking new discrete Cu 6 I 4 cationic clusters, which has a (4, 8)-connected fluorite ( flu ) topological network. Photoluminescent (PL) investigation reveals that compound 1 displays strong yellow-light emission.

An unprecedented [Cu7I4]3+ cationic cluster-based metal–organic framework (MOF) including 1D nanochannels

A new cationic copper–iodine based metal–organic framework compound, [Cu 7 I 4 L 3 (H 2 O)] n ( 1 ) (L = 5-(3-pyridyl)tetrazole), has been synthesized by solvothermal method. X-ray analysis shows that compound 1 is a 3-D metal–organic framework constructed by the L ligands linking new discrete (Cu 7 I 4 ) 3 + cationic clusters, which has an uncommon (3, 9)-connected gfy topological network including 1D hexagonal nano-channels. Presented here is a new 3D metal-organic framework [Cu 7 I 4 L 3 (H 2 O)] n ( 1 ) (L = 5-(3-pyridyl)tetrazole), has been synthesized by solvothermal method. Structural analysis shows that compound 1 is an interesting (Cu 7 I 4 ) 3 + cluster-based metal–organic framework (MOF) with uncommon (3, 9)-connected gfy topology. ► Unprecedented cationic [Cu 7 I 4 ] 3 + cluster was trapped by solvothermal synthesis of an anionic-tetrazolate-based metal organic framework. ► The metal organic framework with unprecedented (3,9)-connected gfy topology. ► Representing the first Cu–I cluster based MOF with the gfy topology and 1D hexagonal nano-channels.

Anion-dependent construction of copper(i/ii)-1,2,4,5-tetra(4-pyridyl)benzene frameworks

The unique tetrapyridyl ligand 1,2,4,5-tetra(4-pyridyl)benzene (bztpy) isolated from previous hydrothermal in situ metal ligand reaction is found to exhibit remarkable anion-dependent assembly of a series of novel metal–organic frameworks (MOFs), [Cu2(CN)2(bztpy)] (1), [Cu(SO4)(bztpy)]·1.5H2O (2), [Cu2Br2(bztpy)]·MeCN (3) and [Cu10I10(bztpy)2]·2H2O (4), which were synthesized under hydro/solvothermal conditions. These MOFs were characterized by elemental analysis, IR and single-crystal X-ray diffraction. Compound 1 consists of [Cu(CN)]n chains that link the neighbouring ones via tetradentate bztpy bridges to form a corrugated 2D layer. When bztpy is treated with CuSO4, a 3D (3,5)-connected network 2 is obtained, in which novel [Cu(bztpy)]n ladders are interconnected by sulfate anions μ-bridges. However, Br− and I− anions assist the formation of {Cu2Br2} and {Cu10I10} SBU in the cluster-based metal–organic frameworks 3 and 4, respectively, and result in a completely different topology. Compound 3 shows a 3D PtS net, while compound 4 has a new 3D (4,8)-connected topology. A discussion of the crystal structures, as well as the coordination behaviour of the special tetrapyridyl ligand upon different geometries of the central connecter is provided. In addition, the photoluminescent properties of 1, 3 and 4 in the solid state at ambient temperature are also investigated.