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A facile amperometric biosensor that included oxidase mimicking Co/2Fe metal-organic framework (MOF) for sialic acid (SA) detection was prepared. Amperometric SA biosensor was constructed on a gold screen-printed electrode via immobilization of Co/2Fe MOF and N-acetylneuraminic Acid Aldolase (NANA-Aldolase) enzyme, respectively. NANA-Aldolase enzyme converts free SA into pyruvate and N-acetyl-D-mannosamine. After this conversion, oxidase mimicking Co/2Fe bimetallic MOF converts pyruvate into acetylphosphate and O2 into H2O2. Investigation of analytical characteristics resulted with the linear range of 0.02 mM–1.00 mM of SA concentration with limit of detection value of 0.026 mM. Sample application studies with developed SA biosensor were carried out with GD3 ganglioside and HeLa cancer cell lines which have high SA concentrations while A549 cell lines were also used as control group. Before detecting free SA, the bound SA was freed from SA sources where every step was monitored via electron impedance spectroscopy. Then, free SA was successfully detected with the amperometric SA biosensor and as a result, more practical and accurate system was developed. © 2022 Elsevier B.V., European Cooperation in Science and Technology, COST: CA18103; Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAK: 119R064, The grant from The Scientific and Technological Research Council of Turkey (TUBITAK) with Project No: 119R064 in the frame of COST Action (CA18103) was greatefully acknowledged.

Herein we propose a new approach for deducing the topology of metal–organic frameworks (MOFs) assembled from organic ligands of low symmetry, which we call net-clipping. It is based on the construction of nets by rational deconstruction of edge-transitive nets comprising higher-connected molecular building blocks (MBBs). We have applied net-clipping to predict the topologies of MOFs containing zigzag ligands. To this end, we derived 2-connected (2-c) zigzag ligands from 4-c square-like MBBs by first splitting the 4-c nodes into two 3-c nodes and then clipping their two diagonally connecting groups. We demonstrate that, when this approach is applied to the 17 edge-transitive nets containing square-like 4-c MBBs, net-clipping leads to generation of 10 nets with different underlying topologies. Moreover, we report that literature and experimental research corroborate successful implementation of our approach. As proof-of-concept, we employed net-clipping to form three new MOFs built with zigzag ligands, each of which exhibits the deduced topology., This work was supported by the Spanish MINECO (project RTI2018-095622-B-I00), the Catalan AGAUR (project 2017 SGR 238), and the ERC under the EU-FP7 (ERC-Co 615954). It was also funded by the CERCA Program/Generalitat de Catalunya. ICN2 is supported by the Severo Ochoa program from the Spanish MINECO (Grant No. SEV-2017-0706).

The past 20 years have witnessed tremendous advances in the field of porous materials, including the development of novel metal–organic frameworks (MOFs) that show great potential for practical applications aimed at addressing global environmental and industrial challenges. A critical tool enabling this progress has been reticular chemistry, through which researchers can design materials that exhibit highly regular (i.e., edge-transitive) topologies, based on the assembly of geometrically matched building blocks into specific nets. However, innovation sometimes demands that researchers steer away from default topologies to instead pursue unusual geometries. In this Perspective, we cover this aspect and introduce the concept of geometry mismatch, in which seemingly incompatible building blocks are combined to generate non-default structures. We describe diverse MOF assemblies built through geometry mismatch generated by use of ligand bend angles, twisted functional groups, zigzag ligands and other elements, focusing on carboxylate-based MOFs combined with common inorganic clusters. We aim to provide a fresh perspective on rational design of MOFs and to help readers understand the countless options now available to achieve greater structural complexity in MOFs., This work was supported by the Spanish MINECO (project RTI2018-095622-B-I00) and the Catalan AGAUR (project 2017 SGR 238). It was also funded by the CERCA Program/Generalitat de Catalunya. ICN2 is supported by the Severo Ochoa program from the Spanish MINECO (Grant No. SEV-2017-0706).

Herein we report a novel, ozone-based method for postsynthetic generation of mesoporosity in metal–organic frameworks (MOFs). By carefully selecting mixed-ligand Zr-fcu-MOFs based on organic ligand pairs in which one ligand has ozone-cleavable olefin bonds and the other ligand is ozone-resistant, we were able to selectively break the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within the MOF framework. This solid–gas phase method is performed at room-temperature, and, depending on the cleavable ligand used, the resultant ligand-fragments can be removed from the ozonated MOF by either washing or sublimation. Compared to the corresponding highly microporous starting MOFs, the highly mesoporous product MOFs exhibit radically distinct gas sorption properties., This work was supported by the Spanish MINECO (projects PN MAT2015-65354-C2-1-R), the Catalan AGAUR (project 2014 SGR 80), and the ERC under the EU-FP7 (ERC-Co 615954). It was also funded by the CERCA Programme/Generalitat de Catalunya. ICN2 acknowledges the support of the Spanish MINECO through the Severo Ochoa Centres of Excellence Programme, under Grant SEV-2013-0295. V.G. thanks the Generalitat de Catalunya for a Beatriu de Pinós fellowship (2014 BP-B 00155) (Marie Curie Fellowship, EU funded project ITHACA). J.A. and H.X. acknowledge the Generalitat de Catalunya for FI fellowships.

Covalent postsynthetic modification (PSM) of metal-organic frameworks (MOFs) has attracted much attention due to the possibility of tailoring the properties of these porous materials. Schiff-base condensation between an amine and an aldehyde is one of the most common reactions in the PSM of MOFs. Here, we report the use of the spray drying technique to perform this class of organic reactions, either between discrete organic molecules or on the pore surfaces of MOFs, in a very fast (1-2 s) and continuous way. Using spray drying, we show the PSM of two MOFs, the amine-terminated UiO-66-NH2 and the aldehyde-terminated ZIF-90, achieving conversion efficiencies up to 20 and 42%, respectively. Moreover, we demonstrate that it can also be used to postsynthetically cross-link the aldehyde groups of ZIF-90 using a diamine molecule with a conversion efficiency of 70%.

Innovative bimetallic MOFs offer more possibilities to further tailor the properties of MOFs, which have attracted great attention for wide applications. However, it is still a great challenge to rationally design bimetallic MOFs due to the lack of a tunable and reasonable hybrid structure architecture. Herein, a new series of bimetallic metal–organic frameworks (MOFs) with tunable pillar linkers were prepared by a one-step synthesis method. These bimetallic MOFs retain the same crystal structure when the mole fraction (based on metal) of the two metals changes from 0 to 1 and both metal ions occupy random nodal positions. The incorporation of a second metal cation has a large influence on the intrinsic properties (e.g. thermal stabilities and band gaps) of the MOFs. Furthermore, these bimetallic MOFs were used as self-sacrificial templates to prepare bimetal oxide catalysts for the oxygen evolution reaction (OER). After pyrolysis, a porous and hierarchical honeycomb-like structure with carbon network covered (bi)metal oxides is formed. Among all the bimetallic MOF-derived catalysts, CoNi1@C showed the best performance for the OER with the lowest Tafel slopes (55.6 mV dec−1) and overpotentials (335 mV on a glassy carbon electrode and 276 mV on Ni foam) at a current density of 10 mA cm−2, which is higher than those of state-of-the-art Co–Ni mixed oxide catalysts derived from MOFs for the OER. Our results indicate that the incorporation of a second metal ion is a promising strategy to tailor the properties of MOFs. More importantly, this new bimetallic MOF family with tunable linkers is expected to serve as a flexible assembly platform to offer broad possibilities for practical applications of MOFs., X. Zhang is grateful to the China Scholarship Council. J. Luo acknowledges the Research Foundation – Flanders (FWO) for a Research Project (G0B3218N), a Research Grant (1529816N) and a travel grant (V410316N) for a Visiting Professorship at the Technical University of Denmark. TZ, PYT and JA acknowledge funding from Generalitat de Catalunya 2017 SGR 327 and the Spanish MINECO project VALPEC (ENE2017-85087-C3). ICN2 acknowledges support from the Severo Ochoa Programme (MINECO, Grant no. SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya. Part of the present work has been performed in the framework of the Universitat Autònoma de Barcelona Materials Science PhD program. TZ has received funding from the CSC-UAB PhD scholarship program. D. P. acknowledges the Research Foundation – Flanders (FWO) for a Ph.D. (aspirant) Fellowship. We thank Iris Cuppens and Dr Fei Wang (Department of Materials Engineering, KU Leuven) for the assistance with EPMA and ICP measurements. Funding from the National Natural Science Foundation of China (No. 21776120), “Minjiang Scholar” Program and key project (No. JZ160480) of Department of Education, Fujian Province, China, and Open Project (No. 201607) of State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University is also acknowledged.

Herein we describe the topological influence of zigzag ligands in the assembly of Zr(IV) metal–organic frameworks (MOFs). Through a transversal design strategy using reticular chemistry, we were able to synthesize a family of isoreticular Zr(IV)-based MOFs exhibiting the bcu—rather than the fcu—topology. Our findings underscore the value of the transversal parameter in organic ligands for dictating MOF architectures., This work was supported by the EU FP7 ERC-Co 615954, the Spanish MINECO (project PN MAT2015-65354-C2-1-R), and the Catalan AGAUR (project 2014 SGR 80). It was also funded by the CERCA Program/Generalitat de Catalunya. ICN2 acknowledges the support of MINECO through the Severo Ochoa Centers of Excellence Program, under Grant SEV-2013-0295. V.G. is grateful to the Generalitat de Catalunya for a Beatriu de Pinos fellowship (2014 BP-B 00155) (Marie Curie Fellowship, EU-funded project ITHACA).

Metal-organic frameworks (MOFs) are a class of novel nanoporous materials with many potential applications. Structural characterization is important because understanding the relationship between the properties of these industrially relevant materials and their structures allows one to develop new applications and improve current performance. Oxygen is one of the most important elements in many MOFs and exists in various forms. Ideally, 17O solid-state NMR (SSNMR) should be an excellent tool for characterizing various oxygen species. However, the major obstacles that prevent applying 17O SSNMR to MOF characterization are the synthetic effort needed for 17O isotopic enrichment and the associated high cost. In this work, we successfully prepared several prototypical 17O-enriched MOFs, including Zr-UiO-66, MIL-53(Al), CPO-27-Mg (or Mg-MOF-74), and microporous α-Mg3(HCOO)6. Depending on the target MOF, different isotopic enrichment methods were used to effectively incorporate 17O from 17O-enriched H2O. Using these 17O-enriched MOFs, we were able to acquire 17O SSNMR spectra at a magnetic field of 21.1 T. They provide distinct spectral signatures of various key oxygen species commonly seen in representative MOFs. We demonstrate that 17O SSNMR can be used to differentiate chemically and, under favorite circumstances, crystallographically nonequivalent oxygens and to follow the phase transitions. The synthetic approaches for preparation of 17O-enriched sample described in this paper are fairly simple and cost-effective.

International audience; The impact of surface deposition on cooperativity is explored in Au(111)-supported self-assembled metal-organic frameworks (MOFs) based on Fe(II) ions. Using a thermodynamic model, we first demonstrate that dimensionality reduction combined with deposition on a metal surface is likely to deeply enhance the spin-crossover cooperativity, going from gamma(3D) = 16 K for the bulk material to gamma(supp)(2D) = 386 K for its 2D supported derivative. On the basis of density functional theory, we then elucidate the electronic structure of a promising Fe-based MOF. A chemical strategy is proposed to turn a weakly interacting magnetic system into a strongly cooperative spin-crossover monolayer with gamma(Au(111))(MOF) = 83 K. These results open a promising route to the fabrication of cooperative materials based on SCO Fe(II) platforms.

Here we report the use of a pillaring strategy for the design and synthesis of three novel amide-functionalized metal-organic frameworks (MOFs), TMUs-22/-23/-24, isoreticular to the recently reported imine-functionalized TMU-6 and TMU-21 MOFs. An extensive study of their CO sorption properties and selectivity for CO over N, from single gas sorption isotherms to breakthrough measurements, revealed that not only the incorporation of amide groups but also their accessibility is crucial to obtain enhanced CO sorption and CO/N selectivity. Therefore, the MOF with more accessible amide groups (TMU-24) shows a CO/N selectivity value of ca. 10 (as revealed by breakthrough experiments), which is ca. 500% and 700% of the selectivity values observed for the other amide-containing (TMU-22 and TMU-23) and imine-containing (TMU-6 and TMU-21) MOFs., This work was supported by the Spanish MINECO (projects PN MAT2015-65354-C2-1-R and MAT2013-45008-P), the Catalan AGAUR (project 2014 SGR 80), and the ERC under the EU FP7 (ERC-Co 615954). I.I. and E.V.R.F. thank the MINECO for their RyC fellowships RYC-2010-06530 and RyC-2012-11427 and V.G. is grateful to the Generalitat de Catalunya for a Beatriu de Pinos Fellowship (2014 BP-B00155). ICN2 acknowledges the support of the Spanish MINECO through the Severo Ochoa Centers of Excellence Program, under Grant SEV-2013-0295. E.V.R.F. and J.S.A. acknowledge the Generalitat Valenciana for PROMETEOII/2014/004. Support of this investigation by Tarbiat Modares University is gratefully acknowledged.

The discovery of new methods for the post-synthesis modification of materials is essential in order to establish suitable strategies for the tuning of their properties in a rational manner. Here we present a series of single-crystal-to-single-crystal (SCSC) transformations for the flexible [Eu2(CIP)2(DMF)2(H2O)2] (UCY-8) [H3CIP = 5-(4-carboxybenzylideneamino)isophthalic acid] and rigid [Eu2(N-BDC)3(DMF)4] (EuN-BDC) (H 2N-BDC = 2-amino-1,4-benzene dicarboxylic acid) Metal-Organic Frameworks (MOFs) that involve the replacement of their coordinating solvent molecules by terminally ligating organic molecules with multiple functional groups including -OH, -SH, -NH- and -NH2 or their combinations, chelating ligands, and two different organic compounds. The capability of the flexible MOF, which contains small pores and channels (Cited By :18

Metal-organic frameworks (MOFs) are appealing candidates for use in energy harvesting and concentrating because of their high chromophore density and structural tunability. The ability to engineer electronic excitation energy transport pathways is of particular interest for designing energy harvesting materials. In this study, theoretical analysis was performed on energy transfer in MOFs that contain light absorbing ruthenium complexes that serve as hopping intermediates for energy transfer kinetics and energy trapping osmium complexes. We find that the excitation transport kinetics is well described by a Dexter (exchange) triplet-to-triplet energy transfer mechanism with multistep incoherent exciton hopping. The modeling combines ab initio electronic structure theory with kinetic network analysis. The sensitivity of Dexter mechanism energy transfer to framework structure establishes different kinds of energy transport paths in the different structures. For example, the mixed Ru/Os MOF structures described here establish one or three-dimensional hopping networks. As such, Dexter mechanism energy harvesting materials may be amenable to designing structures that can spatially direct exciton energy along specific pathways for energy delivery to reaction centers. © 2013 American Chemical Society. 117 43 22250 22259 Cited By :15

A series of new 3-D Ln3+ metal-organic frameworks (MOFs), which are based on the semi-rigid ligand H3CIP [H3CIP = 5-(4-carboxybenzylideneamino)isophthalic acid], [Ln2(CIP) 2(DMF)4-x(H2O)x] (Ln3+ = La3+, Ce3+, Pr3+, Sm3+, Eu 3+, Gd3+, Tb3+, Dy3+, Ho 3+ x = 0-2) are reported. Magnetic susceptibility data for selected compounds indicated the presence of antiferromagnetic interactions, while the photoluminescence properties of the MOFs revealed emission peaks that are red-shifted compared to the emission (405 nm) of the uncoordinated H 3CIP ligand, whereas the Eu3+ and Tb3+ analogues showed emission peaks typical of these lanthanide ions. Single-Crystal-to-Single-Crystal (SCSC) coordinating solvent exchange experiments with acetone and methanol for the Ce3+ analogue afforded compounds that are isostructural with the pristine material and contain one acetone and one water or 1.25 methanol and 0.75 water ligated molecules per Ce3+ respectively. The capability of activated Ce3+ MOF to absorb liquid MeOH was evaluated by means of 1H NMR spectroscopy. The results of the sorption experiments indicated a maximum absorption capacity of 96(2) mg g-1 and fast kinetics, while the sorbent is reusable and is also capable of highly selective sorption of MeOH over EtOH. Overall this work emphasizes the multifunctional nature of lanthanide MOFs and provides insight into the liquid-phase sorption of small organic molecules by such materials demonstrating their high potential as sorbents. © The Royal Society of Chemistry 2013. 1 16 5061 5069 Cited By :21