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UiO-66, a zirconium-based metal–organic framework, was synthesized using a one-step spray synthesis method to investigate the effects of preheating the precursor solution and Zr sources on crystallinity. Using ZrCl4 with water as a modulator requires preheating at 80 °C for 120 min or 120 °C for 30 min for the spray synthesis of UiO-66 to form secondary building units (SBUs). By contrast, the use of Zr(OnPr)4 with acetic acid (AcOH) as a modulator allowed the spray synthesis of UiO-66 and UiO-66-NH2 without preheating because of the rapid formation of SBUs with AcOH. The spray-synthesized UiO-66 using Zr(OnPr)4 exhibited a BET surface area of 1258 m2/g and a CO2 adsorption capacity of 3.43 mmol/g at 273 K and 1 bar, while UiO-66-NH2 exhibited a BET surface area of 1263 m2/g and a CO2 adsorption capacity of 6.11 mmol/g under the same conditions. [ABSTRACT FROM AUTHOR]

In order to investigate the effects of different synthesis conditions on the micro-structures and macro-properties of MOFs, two metal-organic frameworks (MOFs) {[Cu2(L)2 · C2H3N]}n(1) and {[Cu(HL)2]}n(2) were prepared by using the copper sulfate (CuSO4·5H2O) and 6-(pyridin-3'-yl)isophthalic acid (H2L) as the building units under the different reaction conditions. Compound 1 and 2 were fully studied through structure analysis, thermogravimetric analysis (TGA) and FT-IR spectroscopy. Single crystal data reveals that compound 1 and 2 crystallize in the monoclinic crystal system with the P21/c space group. Structure analysis indicates that compounds 1 shows a three-dimensional dense packing structure based on the secondary building units dinuclear paddle wheel shaped [Cu2(COO)4] (SBUs). Structure analysis reveals that compounds 2 shows a 2D layer structure,which was further connected by the hydrogen bonds [O3—H…O4] to give a 3D network. Topological analysis for compounds 1 and 2 show that 1 can be simplified as a two connect rtl network with the point symbol of (4².610.8³),and 2 can be viewed as a unnodol connect sql network with the point symbol of (44.6²). In order to study the properties of the compounds 1 and 2 in aqueous solution, three different dyes were used to characterize the dye degradation properties of 1 and 2 using ultraviolet/visible spectroscopy (UV) at the same time. The degradation properties of compounds 1 and 2 on different dyes at the same time intervals show that compound 2 shows a certain chemical adsorption and degradation ability for malachite green in aqueous solution. [ABSTRACT FROM AUTHOR]

A pair of 2D MOFs, [Tm4(ipO)4(H2O)4] (1) and [Tm2(ipO)2(DMF)(H2O)] (2), have been solvothermally synthesized using 2-hydroxyisophthalic acid (H3ipO) ligand. Both of them are structurally characterized by single-crystal X-ray diffraction, IR, TGA and PXRD. They all consist of [Tm2] Secondary Building Units (SBUs), in which two TmIII ions are double bridged by the Ophenol from ipO3− ligands. It is interesting that the tiny change of the reaction solvents has resulted in structural dissimilarity between them. Two types of centrosymmetric SBUs, namely, [Tm2(ipO)2] and [Tm2(ipO)2(H2O)2], are observed in 1. While 2 is built by the SBUs of [Tm2(ipO)2(DMF)(H2O)], in which two TmIII centers show distinct coordination geometries. Furthermore, the difference in the linkages between the SBUs of two MOFs are also found, though two MOFs show rather similar 2D framework structures. The mesurements of variable temperature magnetic susceptibility revealed the occurrence of weak antiferromagnetic interaction between the TmIII centers in two systems. A pair of 2D TmIII MOFs based on [Tm2] Secondary Building Units have been prepared with 2-hydroxyisophthalic acid ligand. Different coordinated solvents have induced the structural dissimilarity between two MOFs. Magnetic investigation indicated the antiferromagnetic interactions in both systems. [ABSTRACT FROM AUTHOR]

Metal Organic Frameworks (MOFs), built from metal ions/clusters coordinated by organic linkers/bridging ligands, have emerged as an extensive class of crystalline hybrid materials with exceptional ultrahigh porosity and enormous internal surface areas. Out of several hallmarks possessed by MOFs, one is their topologically diverse and aesthetically pleasing framework structures which can be adjusted and tuned with the state-of-art techniques, and molecular simulations, different geometry, and connectivity of a linker to the respective metal cluster. In this critical review, we intend to highlight the scope of carboxylate-based MOFs by providing a varied range from their topology analysis and molecular simulations to different synthetic routes. Moreover, providing insights to reticular chemistry of carboxylate MOFs and the importance of Post-Synthetic Modification (PSM), an alternative route to introduce functional groups within these MOFs. We have also tried to identify the possible loopholes that can provide an extensive opportunity to young researchers that can lead to a detailed exploration in the field of novel MOFs. [ABSTRACT FROM AUTHOR]

Single crystals of tribarium hexahydroxidostannate(IV) bis[selenate(VI)] trihydrate, Ba3H12O17Se2Sn or Ba3[Sn(OH)6][SeO4]2·3H2O, prepared from solid BaSnO3 and aqueous Na2[SeO4] solutions have hexagonal (P63) symmetry. The structure consists of four different primary building units: a hexahydroxidostannate(IV) ion, two different selenate(VI) ions, all three of point group symmetry C3, and a mono-capped {BaO9}-square antiprism of point group symmetry C1. The secondary building units result from three of the barium coordination polyhedra linked together via common edges. While one of the two tetrahedral voids formed from these trimeric units is filled by one bidentate, chelating μ2-selenate ion, the other one remains unoccupied as the corresponding second selenate ion only acts as a monodentate, μ1-ligand. SBUs are completed by hexahydroxidostannate(IV) ions sharing adjacent edges on the uncapped faces of the three, mono-capped square antiprisms. These SBUs are arranged into layers via common edges on the uncapped, square faces of the {BaO9} coordination polyhedra in a way that the hexahydroxidostannate(IV) ions act as linkage between two neighboring layers.

UiO-66, a zirconium-based metal–organic framework, was synthesized using a one-step spray synthesis method to investigate the effects of preheating the precursor solution and Zr sources on crystallinity. Using ZrCl4 with water as a modulator requires preheating at 80 °C for 120 min or 120 °C for 30 min for the spray synthesis of UiO-66 to form secondary building units (SBUs). By contrast, the use of Zr(OnPr)4 with acetic acid (AcOH) as a modulator allowed the spray synthesis of UiO-66 and UiO-66-NH2 without preheating because of the rapid formation of SBUs with AcOH. The spray-synthesized UiO-66 using Zr(OnPr)4 exhibited a BET surface area of 1258 m2/g and a CO2 adsorption capacity of 3.43 mmol/g at 273 K and 1 bar, while UiO-66-NH2 exhibited a BET surface area of 1263 m2/g and a CO2 adsorption capacity of 6.11 mmol/g under the same conditions.

Single crystals of tribarium hexa­hydroxidostannate(IV) bis­[selenate(VI)] trihydrate, Ba3H12O17Se2Sn or Ba3[Sn(OH)6][SeO4]2·3H2O, prepared from solid BaSnO3 and aqueous Na2[SeO4] solutions have hexa­gonal (P63) symmetry. The structure consists of four different primary building units: a hexa­hydroxidostannate(IV) ion, two different selenate(VI) ions, all three of point group symmetry C3, and a mono-capped {BaO9}-square anti­prism of point group symmetry C1. The secondary building units result from three of the barium coordination polyhedra linked together via common edges. While one of the two tetra­hedral voids formed from these trimeric units is filled by one bidentate, chelating μ2-selenate ion, the other one remains unoccupied as the corresponding second selenate ion only acts as a monodentate, μ1-ligand. SBUs are completed by hexa­hydroxidostannate(IV) ions sharing adjacent edges on the uncapped faces of the three, mono-capped square anti­prisms. These SBUs are arranged into layers via common edges on the uncapped, square faces of the {BaO9} coordination polyhedra in a way that the hexa­hydroxidostannate(IV) ions act as linkage between two neighboring layers. [ABSTRACT FROM AUTHOR]

• MOFs 1 − 4 showed multinuclear special 3D pillar-layered structures through adjusting ligands strategy. • MOFs 1 − 4 can promote the electrocatalytic decomposition of water in alkaline media. • MOF 3 obtained lower overpotentials of 180 and 196 mV (10 mA·cm−2) in OER and HER, respectively. • MOFs 1 − 4 exhibit excellent stability during electrolysis over 10 h. Multidentate ligands can be used to construct structurally adjustable metal-organic framework materials due to their abundant coordination sites. MOFs 1 − 4 with different configurations are synthesized by solvothermal method based on the symmetrical tetracarboxylic acid H 4 L main ligand (H 4 L = 5′-(4-carboxyphenyl)-[1,1′:2′,1′'-terphenyl]-4,4′,4′'-tricarboxylic), named [Co 2 (L)(bimb)] n (MOF 1, bimb =(1,1′-(1,4-butanediyl) bis (imidazole)), [Co 2 (L)(bix)] n , (MOF 2, bix =1,4-bis(imidazol-1-ylmethyl) benzene), [Co 4 (L) 2 (bidpe) 2 ] n (MOF 3, bidpe =4,4′-bis(imidazolyl)diphenyl ether) and {[Co 4 (L)(bibdp) 2 (C 3 H 7 NO)]·2(C 3 H 7 NO)} n (MOF 4, bibdp =4,4′-bis(1-imidazolyl) biphenyl), respectively. The rich coordination sites of H 4 L carboxylic acid ligands bring diverse coordination modes, forming Co 2 N 2 O 8 secondary construction units. Based on it, MOFs 1 − 4 exhibits pillar-layered 3D porous supramolecular structure. Electrochemical measurements support that MOFs 1 − 4 exhibits excellent OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) activities, especially MOF 3 , which only requires overpotentials of 180 and 196 mV to reach the current density of 10 mA·cm−2. Remarkable catalytic performance of MOF 3 is attributed to the abundant and dispersed reactive active sites brought by the 3D interpenetrated structure assembled based on tetranuclear metal clusters. The HER occurs through Volmer-Heyrovsky mechanism, meanwhile, possible mechanisms of OER have been predicted. This investigation provides inspiration for exploring multi-core structured MOF materials as efficient HER/OER bifunctional catalysts for electrolytic overall water splitting. [Display omitted] [ABSTRACT FROM AUTHOR]

The title coordination polymer, {[Cu3(C4H4N3O9)3(SeO4)(OH)]·2H2O}n or ([Cu3(μ3-OH)(trgly)3(SeO4)]·2H2O), crystallizes in the monoclinic space group P21/c. The three independent Cu2+ cations adopt distorted square-pyramidal geometries with {O2N2+O} polyhedra. The three copper centres are bridged by a μ3-OH anion, leading to a triangular [Cu3(μ3-OH)] core. 2-(1,2,4-Triazol-4-yl)acetic acid (trgly-H) acts in a deprotonated form as a μ3-κ3N1:N2:O ligand. The three triazolyl groups bridge three copper centres of the hydroxo-cluster in an N1:N2 mode, thus supporting the triangular geometry. The [Cu3(μ3-OH)(tr)3] clusters serve as secondary building units (SBUs). Each SBU can be regarded as a six-connected node, which is linked to six neighbouring triangles through carboxylate groups, generating a two-dimensional uninodal (3,6) coordination network. The selenate anion is bound in a μ3-κ3O1:O2:O3 fashion to the trinuclear copper platform. The [Cu3(OH)(trgly)3(SeO4)] coordination layers and guest water molecules are linked together by numerous O—H...O and C—H...O hydrogen bonds, leading to a three-dimensional structure.

In the development of metal-organic frameworks (MOFs), secondary building units (SBUs) have been utilized as molecular modules for the construction of nanoporous materials with robust structures. Under solvothermal synthetic conditions, dynamic changes in the metal coordination environments and ligand coordination modes of SBUs determine the resultant product structures. Alternatively, MOF phases with new topologies can also be achieved by post-synthetic treatment of as-synthesized MOFs via the introduction of acidic or basic moieties that cause the simultaneous cleavage/reformation of coordination bonds in the solid state. In this sense, we studied the solid-state transformation of two ndc-based Zn-MOFs (ndc = 1,4-naphthalene dicarboxylate) with different SBUs but the same pcu topology to another MOF with sev topology. One of the chosen MOFs with pcu nets is [Zn2(ndc)2(bpy)]n (bpy = 4,4′-bipyridine), (6Cbpy-MOF) consisting of a 6-connected pillared-paddlewheel SBU, and the other is IRMOF-7 composed of 6-connected Zn4O(COO)6 SBUs and ndc. Upon post-structural modification, these pcu MOFs were converted into the same MOF with sev topology constructed from the uncommon 7-connected Zn4O(COO)7 SBU (7C-MOF). The appropriate post-synthetic conditions for the transformation of each SBUs were systematically examined. In addition, the effect of the pillar molecules in the pillared-paddlewheel MOFs on the topology conversion was studied in terms of the linker basicity, which determines the inertness during the solid-state phase transformation. This post-synthetic modification approach is expected to expand the available methods for designing and synthesizing MOFs with controlled topologies. [ABSTRACT FROM AUTHOR]

Hydrothermal reaction of trimethyltin chloride with 1,2,4,5‐benzenetetracarboxylic acid (H4L1), 2,3‐pyridinedicarboxylic acid (H2L2) or 1,4,5,8‐naphthalenetetracarboxylic acid 4,5‐anhydride (H2L3) under optimized pH (5–6) and temperature (130 °C) results in the isolation of new dicarboxylatotetramethyldistannoxane‐based two‐/three‐dimensional coordination assemblies, [{Me2Sn(L1)0.25}2O] (1, 2 as supramolecular isomers), [{Me2Sn(L2)0.5}2O] (3) and [{Me2Sn(L3)0.5}2O] (4). The reaction in each case proceeds with selective cleavage of Sn–C bond. Analogous reaction of trimethyltin chloride with H4L1 at 100 °C affords [Me3Sn(L1)0.25] (5). The supramolecular coordination isomers 1 and 2 with cds and lvt network topologies, respectively are the first representatives among the distannoxane family; the latter confers large solvent accessible voids of 37 % per unit cell. The formation of ladder distannoxane, [{Me2Sn(O2C)}2O]2 as a common structural motif in 1, 3 and 4 is a manifestation of a predefined geometry of the inorganic secondary building unit (SBU) and follows the benchmark of reticular chemistry approach. The coordination assembly, 5 adopts an eight‐connected uninodal net that belongs to bcu topology. These are thermally stable up to 250–400 °C and retain their crystallinity even after exposure to hydrothermal treatment for 24 h. [ABSTRACT FROM AUTHOR]

Four novel 3D Co(II)-containing metal–organic frameworks (MOFs), namely [Co(ADDA)] (1), [Co(ADDA)(bipy)]·1.5H 2 O (2), [Co 0.5 (HADDA)(bipy) 0.5 ] (3) and [Co(ADDA)(bipy) 0.5 ] (4) (H 2 ADDA = 3,3'-(anthracene-9,10-diyl)diacrylic acid, bipy = 4,4′-bipyridine), have been successfully obtained based on reasonable synthetic strategies. N-donor auxiliary ligand, reaction medium and reaction temperature jointly induce interesting transformation of secondary building unit (SBU), resulting in structure diversities and topology variations. Notably, by increasing the reaction temperature in the mother liquid, 4 with {Co 2 (COO) 4 } paddle-wheel SBU can be generated by the single-crystal to single-crystal transformation of 3 with mononuclear {CoO 4 } SBU. Furthermore, the magnetic properties and electrocatalytic activities of these four Co-MOFs are also investigated in detail. • Four novel 3D Co(II)-containing metal–organic frameworks have been successfully synthesized. • N-donor auxiliary ligand, reaction medium and reaction temperature induce transformation of secondary building unit. • It offers insights into construction of new MOFs with SBU transformation for magnetic technology and electrocatalysis. [ABSTRACT FROM AUTHOR]

In the development of metal-organic frameworks (MOFs), secondary building units (SBUs) have been utilized as molecular modules for the construction of nanoporous materials with robust structures. Under solvothermal synthetic conditions, dynamic changes in the metal coordination environments and ligand coordination modes of SBUs determine the resultant product structures. Alternatively, MOF phases with new topologies can also be achieved by post-synthetic treatment of as-synthesized MOFs via the introduction of acidic or basic moieties that cause the simultaneous cleavage/reformation of coordination bonds in the solid state. In this sense, we studied the solid-state transformation of two ndc-based Zn-MOFs (ndc = 1,4-naphthalene dicarboxylate) with different SBUs but the same pcu topology to another MOF with sev topology. One of the chosen MOFs with pcu nets is [Zn2(ndc)2(bpy)]n (bpy = 4,4′-bipyridine), (6Cbpy-MOF) consisting of a 6-connected pillared-paddlewheel SBU, and the other is IRMOF-7 composed of 6-connected Zn4O(COO)6 SBUs and ndc. Upon post-structural modification, these pcu MOFs were converted into the same MOF with sev topology constructed from the uncommon 7-connected Zn4O(COO)7 SBU (7C-MOF). The appropriate post-synthetic conditions for the transformation of each SBUs were systematically examined. In addition, the effect of the pillar molecules in the pillared-paddlewheel MOFs on the topology conversion was studied in terms of the linker basicity, which determines the inertness during the solid-state phase transformation. This post-synthetic modification approach is expected to expand the available methods for designing and synthesizing MOFs with controlled topologies. [ABSTRACT FROM AUTHOR]

Central metal exchange can innovatively open the cavity of metal-organic frameworks (MOFs) by alternating the framework topology. Here, the single-crystal-to-single-crystal (SC-SC) transformation is reported from a Co-based MOF {[Co 1.25 (HL) 0.5 (Pz-NH 2 ) 0.25 (µ 3 -O) 0.25 (µ 2 -OH) 0.25 (H 2 O)]·0.125 Co·0.125 L·10.25H 2 O} n (Co-MOF, L = 5,5'-(1H-2,3,5-triazole-1,4-diyl)diisophthalic acid) into two novel MOF materials, {[Cu 1.75 L 0.75 (Pz-NH 2 ) 0.125 (µ 3 -O) 0.125 (µ 2 -OH) 0.25 (H 2 O) 0.375 ]•3CH 3 CN} n (Cu-MOF) and {[Zn 1.75 L 0.625 (Pz-NH 2 ) 0.25 (µ 3 -O) 0.25 (µ 2 -O) 0.25 (H 2 O) 1.25 ]•4CH 3 CN} n (Zn-MOF), through exchanging the Co 2+ in the MOF into Cu 2+ or Zn 2+ , respectively. The free Co 2+ and L 4- in the Co-MOF channels fuse with the skeleton during the Co→Cu and Co→Zn exchange processes, leading to the expansion of the channel space and the transformation of the secondary building units (SBUs) to form an adjustable skeleton. The nonlinear optical response results show that the MOFs generated by the exchange of the central metal exhibit different saturable absorption and the self-focusing effect. In addition, loading polypyrrole (PPy) into the MOFs can not only improve the stability of the MOFs but also further optimize the nonlinear optical behavior. This work suggests that SC-SC central metal exchange and the introduction of polymer molecules can tune the nonlinear optical response, which provides a new perspective for the future study of nonlinear optical materials., (© 2023 Wiley-VCH GmbH.)

The title coordination polymer, {[Cu3(C4H4N3O9)3(SeO4)(OH)]·2H2O}n or ([Cu3(μ3-OH)(trgly)3(SeO4)]·2H2O), crystallizes in the monoclinic space group P21/c. The three independent Cu2+ cations adopt distorted square-pyramidal geometries with {O2N2+O} polyhedra. The three copper centres are bridged by a μ3-OH anion, leading to a triangular [Cu3(μ3-OH)] core. 2-(1,2,4-Triazol-4-yl)acetic acid (trgly-H) acts in a deprotonated form as a μ3-κ³N¹:N²:O ligand. The three triazolyl groups bridge three copper centres of the hydroxo-cluster in an N¹:N² mode, thus supporting the triangular geometry. The [Cu³(μ3-OH)(tr)3] clusters serve as secondary building units (SBUs). Each SBU can be regarded as a six-connected node, which is linked to six neighbouring triangles through carboxylate groups, generating a two-dimensional uninodal (3,6) coordination network. The selenate anion is bound in a μ3-κ³O¹:O²:O³ fashion to the trinuclear copper platform. The [Cu3(OH)(trgly)3(SeO4)] coordination layers and guest water molecules are linked together by numerous O--H···O and C--H···O hydrogen bonds, leading to a three-dimensional structure. [ABSTRACT FROM AUTHOR]

Highlights • Strategies for the construction of multicomponent metal–organic frameworks are reviewed. • Designing diversified secondary building units and linkers is essential. • Reticular chemistry concept is important for multicomponent MOF construction. Abstract Metal–organic frameworks (MOFs) are ideal reticulated space architectures in which well-defined building units with designed functionalities could be precisely positioned in an ordered way. Incorporating multicomponents into MOFs generates crystalline solids with multiple functionalities and tailored pore environments. Intriguing properties and sophisticated functions are expected to emerge owing to the synergies between multiple components. In this review, we provide an overview of recent progress in the discoveries of MOFs with multiple inorganic building units and/or organic linkers. We summarized strategies to introduce multiple organic linkers with different linker geometry, length, size, and coordinating moiety. We also highlight several representative approaches to construct multiple inorganic units for the framework assemblies. These ternary and quaternary MOFs represent a high level of structural complexity in crystalline solids. [ABSTRACT FROM AUTHOR]

The concept of secondary building units (SBUs) is central to all science on metal‐organic frameworks (MOFs), and they are widely used to design new MOF materials. However, the presence of SBUs during MOF formation remains controversial, and the formation mechanism of MOFs remains unclear, due to limited information about the evolution of prenucleation cluster structures. Here in situ pair distribution function (PDF) analysis was used to probe UiO‐66 formation under solvothermal conditions. The expected SBU—a hexanuclear zirconium cluster—is present in the metal salt precursor solution. Addition of organic ligands results in a disordered structure with correlations up to 23 Å, resembling crystalline UiO‐66. Heating leads to fast cluster aggregation, and further growth and ordering results in the crystalline product. Thus, SBUs are present already at room temperature and act as building blocks for MOF formation. The proposed formation steps provide insight for further development of MOF synthesis. Nucleation: In situ pair distribution function analysis was used to reveal the atomic scale nature of precursor species during solvothermal UiO‐66 MOF synthesis, and a hexanuclear zirconium cluster was established as the secondary building unit present, even in the metal salt precursor solution. [ABSTRACT FROM AUTHOR]

Al-MOFs have diverse chemical structures and tunable properties for potential applications in adsorption, separation, catalysis, proton conduction, chirality, and superhydrophobicity fields. [Display omitted] • Systematically summarized the similarities between secondary building units and linkers from the structural aspect of Al-MOFs, the structurally-led approach is distinctive and helps to better understand the crystal chemistry of Al-MOFs. • Introduced the research progress and highlighted several exciting discoveries of studying Al-MOFs. • Demonstrated the development trends, emerging challenges, and opportunities primarily oriented to their scalable production, and aimed at exploring the future application prospects of Al-MOFs from academic research to industrial production. It is essential to explore metal–organic frameworks (MOFs) with high durabilities and versatile properties for practical applications. Multiple metal ions have been utilized to construct MOFs, among which the aluminum ion (Al3+) has drawn intensive attention due to its low toxicity, abundant reserves in the earth, low cost, and sustainability. As an attractive MOF family in virtue of its diverse structures and functions, Al-MOFs exhibit high physicochemical stability and have wide applications in many scientific and engineering fields, due to the diverse secondary building units (SBUs) of Al3+ and the strong Al-O bond. In this review, we systematically summarize the SBUs and linkers from a structural perspective. We also highlight the research progress of Al-MOFs with novel topologies and structures. According to the composition of Al-metal nodes, Al-MOFs can be divided into Al3+-ions, Al3+-chains, or Al3+-clusters. In addition, the potential applications of Al-MOFs in various fields, including adsorption, separation, photocatalysis, electrochemistry, chirality, and superhydrophobicity are discussed. From the perspective of Al-MOF structures, the relationship between the structure and performances of Al-MOFs is reviewed, and the future application prospects of Al-MOFs are discussed. [ABSTRACT FROM AUTHOR]

According to hard and soft (Lewis) acids and bases (HSAB) theory, a novel 3d-3d heterometallic-organic framework based on Cu 4 I 4 clusters and binuclear Zn(II) moieties was successfully synthesized. The linkage of different secondary building units (SBUs) with the bifunctional ligand which contains N and O atoms simultaneously generates an intriguing 2-fold interpenetrated network. The synthesis, structural characterization and photoluminescence property of the compound have been investigated. [ABSTRACT FROM AUTHOR]

For the past 20 years, metal-organic frameworks (MOFs) have been appealing to the material scientists due to their unique properties and varied applications. MOFs are built using metal ions and selected organic ligands/linkers, viz. multidentate carboxylates, N-containing carboxylates, heterocyclic compounds, etc. The properties of naphthalenedicarboxylate (NDC) ligands, such as flexibility, viable coordination modes, bulkiness and good ligation nature to sequester metal ions in different orientations make them particularly attractive for the synthesis of MOFs. The two carboxylate groups present in the NDC ligand promote various coordination modes, which prompt diverse MOF structures with good porosity. The coordination of NDC ligands with metal ions, mostly Zn(II), Cd(II), Mn(II), Co(II), Ag(I) and lanthanides have created MOFs with different networks and topologies, with innovative applications in the fields of gas storage, gas separation, luminescence, catalysis, drug delivery and magnetism. The choice of precursors, the reaction environment including temperature, metal/ligand ratio, solvent, pH, can profoundly affect the architecture of MOFs and quantitatively influence their probable applications. The virtues of MOFs have led to their extensive adoption in varied fields. This review provides a comprehensive insight into the design and synthesis of various MOFs using NDC ligands and their probable applications. [ABSTRACT FROM AUTHOR]

In this work, we present a new feasible way to synthesise cellulose nanocrystal (CNC) aerogel by the use of the secondary building units (organic carboxyl ligand), what had been extensively used in the building of cubic-structured metal organic frameworks (MOFs). The linear paddle-wheel structure of NHNH-BDC-NHNH endows CNC aerogels with high elasticity and fast oil/water separation. The porosity and density of CNC aerogels could be regulated by different contents of NHNH-BDC-NHNH and CHO-CNCs. Three mixing methods, such as vortexing, double-barrel blending and sonication, were carefully performed to investigate their formation of CNC aerogels. The density of the aerogels ranged from 22.4 to 23.3 mg/cm and specific surface areas were 195-303 ± 10 m/g characterized by Brunauer-Emmett-Teller analysis. The structural analysis of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the bimodal pore distribution and the hydrazone-carboxyl ligand-linked structure. On the basis of the porosity of 96.3-97.2%, the absorption capacity of aerogels was 133 ± 6 g/g for water, was 99 ± 8 g/g for ethanol, was 34 ± 4 g/g for toluene, and was 54 ± 6 g/g for dodecane. The CNC aerogels showed excellent mechanical properties and shape recovery ability in water and air. Meanwhile, the results indicate that more carboxyl on organic linkers can improve the properties of elasticity and separation for aerogels. [ABSTRACT FROM AUTHOR]

This paper describes the preparation of four 3 d –4 f (3 d = Zn; 4 f = Eu, Tb) coordination polymers and their emission quenching of the lanthanide ions. Two dinuclear Zn–Ln compartment compounds, [ZnLn(L)(NO 3 )(CH 3 CN)(H 2 O) 4 ](NO 3 ) 2 (H 2 O) (Ln = Eu, Tb), were prepared at room temperature by stirring an acetonitrile solution containing [Zn(L)] (H 2 L = 1,3-bis((3-methoxysalicylidene)amino)propane) and Ln(NO 3 ) 3 · n (H 2 O). When these compounds were treated with 4-pyridinepropionic acid (4-Hppa) under microwave-heating conditions, one-dimensional Zn–Ln coordination polymers were formed: [ZnLn(L)(NO 3 ) 2 (4-ppa)(EtOH)] (Ln = Eu ( 1 ), Tb ( 2 )). By contrast, these compounds reacted with pyridine-4-carboxylic acid (4-Hpca) to give two-dimensional Zn–Ln coordination polymers: [ZnLn(L)(NO 3 ) 2 (4-pca)(H 2 O)] (Ln = Eu ( 3 ), Tb ( 4 )). All the compounds ( 1 – 4 ) exhibited the emission quenching of the Ln 3+ ion, probably due to the Ln 3+ → Zn 2+ energy transfer. [ABSTRACT FROM AUTHOR]

The syntheses of three new coordination polymers, {Cu2(tci)(btx)0.5(µ3-OH)(H2O)}n (1), {Cu1.5(tci)(biip)}n (2), {Co1.5(tci)(biip)}n (3), have been reported. The structural analysis reveals that the compound 1 is a one-dimensional structure whereas compounds 2 and 3 are three- dimensional architectures. Interestingly, all the compounds consist of two distinct coordination geometries/chemical environment in their SBUs in the respective crystal structures. Compounds 1–3 have been characterized by gas adsorption studies besides routine spectral and elemental analyses. [Display omitted] Three new metal–organic framework (MOF) containing compounds, namely {Cu 2 (tci)(btx) 0.5 (µ 3 -OH)(H 2 O)} n (1), {Cu 1.5 (tci)(biip)} n (2), {Co 1.5 (tci)(biip)} n (3) [H 3 tci = tris(2-carboxyethyl)isocyanurate, btx = 1,4-bis(triazol-1-yl-methyl)benzene, biip = 3,5-bis(imidazole-1-yl)pyridine] have been successfully synthesized through the assembly of metal ions [Cu(II) ion for compounds 1 and 2 , Co(II) for compound 3 ] with H 3 tci and two different N -donor ligands (btx and biip) under solvothermal conditions. All compounds were characterized by IR spectroscopy, elemental and thermogravimetric (TG) analyses, powder X-ray diffraction (PXRD) studies and finally, the structures of all compounds were unambiguously determined by single-crystal X-ray diffraction (SCXRD) technique. Compound 1 is a 1D coordination polymer, constructed by the connectivity of copper tetramer as a secondary building unit (SBU) with the H 3 tci and btx ligands. Whereas the crystal structure of compound 2 possesses two different SBUs i.e., paddlewheel and square planar involving Cu(II). The connectivity of these two SBUs results in the formation of 2D layers which are further pillared by biip ligand to result in a 3D structure. In the case of compound 3 , both Co1 and Co2 exhibit distorted octahedral geometry in their SBUs. Further, the connectivity of these SBUs with tci3- and biip ligands results in the formation of a 3D framework. [ABSTRACT FROM AUTHOR]

Novel 3D networks synthesized by two different methods are reported in this article. Structure 1 {[Cd L 2 ]·(solvent)} n consists of Cd II -single metallic nodes held together by coordinated isonicotinate ligands ( L ) to form a 3D chiral framework ( P 4 1 2 1 2). The resulting structure exhibits threefold-interpenetrated dia coordination networks. After a few weeks the crystals were re-measured to form 1a {[Cd( L ) 2 (H 2 O)]·DMF} n with two interpenetrated dia nets which is thermodynamically more stable. On the other hand, the addition of the tin(IV)-porphyrin to the same reaction mixture led to the formation of 3D pseudo-isostructures, based on oxo-centered Cd II and Mn II/III cluster nodes, 2 {[Cd 3 (OH) L 4 (H 2 O) 3 ](ClO 4 )} n and 3 {[Mn 3 (O) L 4 (DMF) 3 ](ClO 4 )} n . These structures represent topologically bcg nets. Possible synthetic mechanism was proposed to emphasize the role of the tin(IV)-porphyrin that led to the construction of oxo-centered trinuclear clusters in 2 and 3 . [ABSTRACT FROM AUTHOR]

Metal–Organic Frameworks (MOFs) are counterpart of many porous entities and are pertinent materials for future needs in almost in every sphere of life. The augmentation in the study of MOFs elicits significant information related to many potential applications. There are many systematic and facile synthetic routes such as hydro/solvothermal technique, microwave, electrochemical and mechanochemical etc. The experimentation, approximation by trial-and-error approaches is still applicable for the preparation of metal organic framework materials. The strategies used in the design of MOFs play crucial role in point of view of the desired application. This review compiles and describes varied eccentric traits of MOFs, synthetic approaches, and mechanisms corresponding to applications in the comprehensible way. The remarkable achievements by researchers in the field of MOFs for targeted applications and the way forward to take up the measures to design and develop MOFs are also addressed. [ABSTRACT FROM AUTHOR]

One novel two-fold interpenetrating 3D coordination polymer [Dy(L)(SO4)(H2O)] (1) (H2L = 6-hydroxypyridine-3-carboxylic acid) has been synthesized and characterized by elemental analyses and single-crystal X-ray diffraction, respectively. Interestingly, L and sulfate anions came from thein situcleavage of a sulfide–sulfide bond of the flexible 6,6′-dithiodinicotinic acid in the hydrothermal reactions. In the structure of1, the L ligands connect the (–Dy–SO4–)∞inorganic rod secondary building units to form a 3D (3,5)-connected (42.65.83)(42.6) net, interlocking the 3D network leads to a twofold parallel interpenetration network. In addition, thermal stability of1was also investigated. [ABSTRACT FROM AUTHOR]

Uranium phosphonates, an important class of actinide-organic coordination polymers, exhibit an exceptionally diverse and broad range of crystal structures. A variety of structure topologies have been identified for hexavalent uranium phosphonates, including cage clusters, chains, ribbons and tubes, sheets, and three-dimensional frameworks. In contrast, only a handful of tetravalent uranium phosphonates are known. This review presents a comprehensive account of the crystal structures of uranium phosphonates and the various building units ( e.g. discrete monomers, polymeric units, infinite chains, and sheets) that result from the numerous coordination modes of phosphonate ligands with uranium. [ABSTRACT FROM AUTHOR]

A series of mesoporous silicoaluminophosphates (MESO-SAPOs) with different silica contents were synthesized using the microporous precursors of SAPO-37 (MESO-SAPO-37). Various analytical and spectroscopic techniques revealed the presence of mesoporous and microporous properties of the materials. The resulting materials were applied to vapor-phase hydroisomerization of 1-octene to afford the corresponding branched alkenes in good yields under ambient conditions. The catalytic activity of MESO-SAPO-37 was compared to those of other mesoporous analogs obtained from SAPO-34 and SAPO-5 precursors. Among all the synthesized materials, MESO-SAPO-37 showed the best catalytic activity owing to the presence of faujasite units. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are constructed by linking inorganic units with organic linkers to make extended networks. Though more than 20 000 MOF structures have been reported most of these are ordered and largely composed of a limited number of different kinds building units, and very few have multiple different building units (heterogeneous). Although heterogeneity and multiplicity is a fundamental characteristic of biological systems, very few synthetic materials incorporate heterogeneity without losing crystalline order. Thus, the question arises: how do we introduce heterogeneity into MOFs without losing their ordered structure? This Review outlines strategies for varying the building units within both the backbone of the MOF and its pores to produce the heterogeneity that is sought after. The impact this heterogeneity imparts on the properties of a MOF is highlighted. We also provide an update on the MOF industry as part of this themed issue for the 150th anniversary of BASF. [ABSTRACT FROM AUTHOR]

A novel non-interpenetrated lanthanide–organic framework constructed by dinuclear cerium cluster as pillar and trinuclear cerium cluster as layer with a uniform (3,8)-connected topology has been reported, which exhibits mesoporous cages between layers and 3D interconnected channels. [ABSTRACT FROM AUTHOR]

We have successfully synthesized and characterised a metal-organic framework Ni 6 (μ 3 -OH) 2 (H 2 BTB)(HBTB) 3 (BTB) 2 (H 2 O) 5 ]·13H 2 O (1), which is a twelve-connected 3D framework with (32.4) 2 (38.422.524.610.72) topology. The magnetic behavior of 1 shows that an antiferromagnetic coupling among the Ni ions is observed. [Display omitted] • A twelve-connected 3D metal-organic framework was successfully synthesized and charactered. • The newly synthesized MOF is based on a rare mixed-equilibrium Ni6 metal cluster and a tripod ligands. • There exists predominantly antiferromagnetic interaction between the Ni centers. A novel (3,12)-connected framework [Ni 6 (μ 3 -OH) 2 (H 2 BTB)(HBTB) 3 (BTB) 2 (H 2 O) 5 ]·13H 2 O with (32.4) 2 (38.422.524.610.72) topology has been prepared by self-assembly of benzene-1,3,5-tribenzoates and two hexanuclear nickel carboxylate clusters under hydrothermal conditions. The magnetic property of this compound was investigated in the temperature range of 2.0–300.0 K under an outer field of 2000 Oe. The result shows the dominant antiferromagnetic interaction between Ni centers. [ABSTRACT FROM AUTHOR]

A new Cu(II) metal-organic framework {[Cu 1.5 (1,3-bdc)(dtb)(OH)(H 2 O)](H 2 O)} n ( 1 ) (1,3-H 2 bdc = 1,3-benzenedicarboxylic acid, dtb = 1,3-di-(1,2,4-triazole-4-yl)benzene), has been synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, and IR spectra. Compound 1 features a 3-D open framework constructed by infinite 1D rod-shaped [Cu 3 (OH) 2 ] n chains as secondary building units. The magnetic property of the complex has also been investigated. [ABSTRACT FROM AUTHOR]

A rare example of chelating two tetra cationic paddle-wheel zinc dimers were synthesized from the reaction between flexible imidazolium carboxylate ( L H B r) and corresponding zinc precursors. A zinc coordination polymer was synthesised by treating in situ generation of 2 in the presence of 4,4'-bipyridine. These new molecules, dimers and polymer, were characterized by FT-IR, NMR, UV-vis, fluorescent and single crystal X-ray diffraction techniques. Zinc polymer is the first example of 1D coordination polymer constructed by tetra cationic zinc dimer as a secondary building unit in coordination polymer. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Single crystals of tribarium hexa-hydroxidostannate(IV) bis-[selenate(VI)] trihydrate, Ba 3 H 12 O 17 Se 2 Sn or Ba 3 [Sn(OH) 6 ][SeO 4 ] 2 ·3H 2 O, prepared from solid BaSnO 3 and aqueous Na 2 [SeO 4 ] solutions have hexa-gonal ( P 6 3 ) symmetry. The structure consists of four different primary building units: a hexa-hydroxidostannate(IV) ion, two different selenate(VI) ions, all three of point group symmetry C 3 , and a mono-capped {BaO 9 . The secondary building units result from three of the barium coordination polyhedra linked together C 1 . The secondary building units result from three of the barium coordination polyhedra linked together via common edges. While one of the two tetra-hedral voids formed from these trimeric units is filled by one bidentate, chelating μ 2 -selenate ion, the other one remains unoccupied as the corresponding second selenate ion only acts as a monodentate, μ 1 -ligand. SBUs are completed by hexa-hydroxidostannate(IV) ions sharing adjacent edges on the uncapped faces of the three, mono-capped square anti-prisms. These SBUs are arranged into layers via common edges on the uncapped, square faces of the {BaO 9 } coordination polyhedra in a way that the hexa-hydroxidostannate(IV) ions act as linkage between two neighboring layers., (© Reuter and Kamaha 2022.)

Abstract: This review details the syntheses, structures and properties of imide-based ligands (phthalimide analogues have been excluded) and structurally characterised coordination complexes of them. The surveyed imide complexes, including 3D-metal-organic frameworks and 1D-polymers formed from monometallic building block complexes, exhibit a wide range of interesting properties, including single chain and single molecule magnetism, spin crossover, reversible electrochemistry and luminescence. [Copyright &y& Elsevier]

Abstract: Two new two-dimensional (2D) metal–organic frameworks constructed from mixed 3-carboxymethoxy phenyl acrylic acid (3-H2cpa) and 4,4′-bipyridine (4,4′-bipy) ligands, [Zn(3-cpa)(4,4′-bipy)0.5] n (1) and [Mn(3-cpa)(4,4′-bipy)0.5(H2O)2] n (2), have been synthesized under hydrothermal condition and characterized by elemental analyses, IR, and single crystal X-ray diffraction techniques. Complex 1 presents a 2D layer framework along the (100) plane, which is derived from paddle wheel units Zn2(COO)4 as secondary building units (SBUs) linked further by 3-cpa and 4,4′-bipy ligands. Complex 2 shows a 2D polymeric framework assembled by wave-like [Mn(3-cpa)] n chains and linear 4,4′-bipy ligands. The luminescence property of 1 in the solid state has been further studied, and result reveals that it displays luminescent property in the green region. [Copyright &y& Elsevier]

Abstract: Two new zinc-triazole-biphenyldicarboxylate frameworks based on secondary building units (SBUs), namely, Zn4(μ4-O)(trz)2(4,4′-bpdc)2 ( 1 ) and Zn2(trz)2(2,4′-bpdc) ( 2 ), [Htrz = 1,2,4-triazole, H2bpdc = biphenyldicarboxylate] have been synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction analyses, X-ray power diffraction, elemental analyses, infrared absorption spectra, and thermogravimetric analyses. Compound 1 is a 2-fold interpenetrating diamond topology constructed from [Zn4(μ4-O)(trz)2]4+ SBUs with tetrahedral [Zn4(μ4-O)] core and two trz ligands. Compound 2 is a 2D 6-connected hxl network based on [Zn2(trz)2]2+ SBUs. Additionally, these two compounds show emission properties at room temperature in the solid state. [Copyright &y& Elsevier]

Abstract: Three-component reactions involving Ni(II) ions and dicarboxylate and bipyridyl ligands under hydrothermal conditions produce two novel metal–organic coordination polymers formulated empirically as [Ni(PDA)(BPE)] (1) and [Ni2(PDA)2(BPP)(H2O)]·2.5H2O (2), where PDA=1,4-phenylenediacetate, BPE=1,2-bis(4-pyridyl)ethane, and BPP=1,3-bis(4-pyridyl)propane. Both compounds possess 2D or 3D metal–organic frameworks (MOFs) that are assembled on dinickel-carboxylate secondary building units. Compound 1 has a condensed 3D MOF, whereas 2 contains void between 2D MOFs where guest water molecules reside. Both compounds demonstrate antiferromagnetic coupling between Ni(II) ions. [ABSTRACT FROM AUTHOR]

Abstract: Two new zinc–triazole–carboxylate frameworks constructed from secondary building units (SBUs), [Zn5(trz)4(btc)2(DMF)2(H2O)2]·2H2O·DMF (1) and [Zn4(trz)3(btc)2(CH3CN)(H2O)]·5H2O·(Bu4N) (2), [Htrz=1,2,4-triazole, H3btc=1,2,4-benzenetricarboxylate, Bu4N=tetrabutylammonium], have been synthesized by solvothermal reactions and characterized by single-crystal X-ray diffraction analyses, X-ray power diffraction, elemental analyses, infrared spectra and thermogravimetric analyses. Both compounds 1 and 2 exhibit 3D (3,8)-connected tfz-d nets with {43}2{46.618.84} topology symbol built from rod-shaped {[Zn5(trz)4]6+} n SBUs (1) and {[Zn4(trz)3]5+} n SBUs (2). In two compounds, rodlike units are connected by btc ligands via different modes. Additionally, solid state fluorescent emission spectra of two compounds show fluorescent properties at room temperature. [ABSTRACT FROM AUTHOR]

Two novel three-dimensional (3-D) coordination polymers, [Pb(HTDA)] (1) and [Co(TDA)(HTDA)(HO)] (2) [HTDA = 1H-1,2,3-triazole-4,5-dicarboxylic acid], have been prepared by hydrothermal reactions and characterized by elemental analysis, infrared spectroscopy and single-crystal X-ray diffraction. Compound 1 is constructed from rod-shaped secondary building units (SBUs) and exhibits a 3-D network with (4·6)(4·6·8) topology. Compound 2 is built up from ligands bridging three different cobalt ions and exhibits a 3-D network with (4·8)(4·8·10) topology. In addition, the thermal stabilities of the two compounds, the photoluminescence properties of compound 1 and the magnetic properties of compound 2 have been studied. [ABSTRACT FROM AUTHOR]

Abstract: Two coordination polymers with the same mixed ligands but different metal ion, [Cd5(bpp)6(μ 1,1-N3)6(μ 2-Cl)2Cl2]n (1) and {[Ni2(bpp)4(N3)4]·0.5H2O}n (2) (bpp=1,3-bis(4-pyridyl)propane), have been hydrothermally synthesized and fully structural characterized. Complex 1 exhibits an eight-connected bcu-type 3D framework with end-on azido-aggregated neutral pentanuclear clusters periodically extended by neutral bpp linkers. Instead, 2 reveals an interpenetrated 2D (4, 4) undulated layer assembled from the octahedral Ni(II) nodes and bridging bpp connectors with monodentate azide anions terminally attached on both sides. Additionally, in contrast to non-fluorescent 2, solid complex 1 displays an intense luminescent emission resulted from the ligand-to-metal charge-transfer upon the cation binding. [Copyright &y& Elsevier]

Abstract: Reactions of nitrilotris(methylenephosphonic acid), [N(CH2PO3H2)3] (NTP) with cadmium acetates under different hydrothermal conditions result in two novel 3D cadmium organotriphosphonates complexes: Na|Cd2[N(CH2PO3H)(CH2PO3)2(H2O)] (1) and Na2|Cd5[N(CH2PO3)3]2(H2O)2| (2). Single-crystal X-ray diffraction analysis reveals that complex 1 crystallizes in monoclinic P21/c (No. 14), with a =11.9730(3)Å, b =10.5928(3)Å, c =9.4435(2)Å, β =97.881(2)°, V =1186.38(5)Å3, and Z =4. Complex 2 is monoclinic C2/c (No. 15) having unit cell parameters a =25.377(5)Å, b =10.543(2)Å, c =9.7160(19)Å, β =107.22(3)°, V =2482.9(9)Å3, and Z =4. The structures of complexes 1 and 2 both feature 3D coordination networks built from cadmium octahedral linked together by bridging phosphonate groups from NTP, sodium cations are deposited in the free volume of the structures. Hydrogen bonds are existed in structures. Notably, SBU-1 (Cd2(NTP)) and SBU-2 (Cd3(NTP)), formed by deprotonated NTP chelating with cadmium atoms, are present in the structure of complexes 1 and 2, respectively. The effect of the extent of deprotonation of phosphonic acids on the type of complex formed is discussed. Further characterizations of the two complexes have been performed, including X-ray powder diffraction, ICP, CHN, IR and TG–DTA analyses. [Copyright &y& Elsevier]

Abstract: Co3O4 nanoparticles are prepared via converting cobalt oxide subunits in a cobalt metal-organic framework (Co3(NDC)3(DMF)4, NDC=2,6-naphthalene- dicarboxylate; DMF=N,N′-dimethylformamide) by pyrolysis in air. The as-prepared Co3O4 shows an agglomerated secondary structure with an average diameter of around 250nm comprised of small primary Co3O4 particles with a size of about 25nm. This agglomerated structure favors the enhanced capacity, improved rate capability and prolonged cycle life as an electrode material for lithium ion batteries. [Copyright &y& Elsevier]