Metal-organic Materials Research Articles

Use of PtC Nanotips for Low-Voltage Quantum Tunneling Applications.

The use of focused ion and focused electron beam (FIB/FEB) technology permits the fabrication of micro- and nanometer scale geometries. Therefore, FIB/FEB technology is a favorable technique for preparing TEM lamellae, nanocontacts, or nanowires and repairing electronic circuits. This work investigates FIB/FEB technology as a tool for nanotip fabrication and quantum mechanical tunneling applications at a low tunneling voltage. Using a gas injection system (GIS), the Ga-FIB and FEB technology allows both additive and subtractive fabrication of arbitrary structures. Using energy dispersive X-ray spectroscopy (EDX), resistance measurement (RM), and scanning tunneling microscope (STM)/spectroscopy (STS) methods, the tunneling suitability of the utilized metal–organic material–platinum carbon (PtC) is investigated. Thus, to create electrode tips with radii down to 15 nm, a stable and reproducible process has to be developed. The metal–organic microstructure analysis shows suitable FIB parameters for the tunneling effect at high aperture currents (260 pA, 30 kV). These are required to ensure the suitability of the electrodes for the tunneling effect by an increased platinum content (EDX), a low resistivity (RM), and a small band gap (STM). The STM application allows the imaging of highly oriented pyrolytic graphite (HOPG) layers and demonstrates the tunneling suitability of PtC electrodes based on high FIB aperture currents and a low tunneling voltage.

Chelation and AOP Approach on Mn-Metal and COD Reduction of Liquid Laboratory Waste

Heavy metal waste and organic material used in flushing laboratory glassware can accumulate and potentially damage the environment. Thus, it needs to be processed before being disposed of to avoid any damage to the aquatic ecosystem. This research aimed to determine the pH wastewater sample and APDC concentration as chelating agents that would be the best for chelation treatment and determine the H2O2 concentration and UV exposure duration to identify the best treatment for the advanced oxidation process. This research was expected to find an alternative in wastewater treatment and provide an overview of the interaction of chelation treatment with organic pollutants as the basis for AOP-treatment management. Laboratory wastewater quality has improved through the extraction treatment of chelate from the pH 4 experiment, ammonium pyrrolidine dithiocarbamate (APDC) concentration at 7.5% with the manganese metal value decreased by 53%, an advanced oxidation process (AOP) treatment of H2O2 concentration at a 5.10-5%, and 31-hour UV exposure, resulting in chemical oxygen demand (COD) decreased by 98.98%. Waste containing both materials was reduced by combining the extraction of chelate formation and AOP, which was detected from the presence of manganese metal and the COD. This treatment can be an appropriate and easy way to degrade laboratory waste in a mini wastewater treatment process. This research succeeded in finding several novelties: first, a suitable pH value to reactivate Mn metal for chelation with APDC; second, the concentration of APDC determined to optimize the Mn metal chelate; third, the concentration of H2O2 to increase the effectiveness of organic matter reduction; fourth, the duration of UV irradiation is effective and efficient as a photocatalyst to reduce organic matter.

Recent advances in metal-organic framework-based materials for anti-staphylococcus aureus infection.

The rapid spread of staphylococcus aureus (S. aureus) causes an increased morbidity and mortality, as well as great economic losses in the world. Anti-S. aureus infection becomes a major challenge for clinicians and nursing professionals to address drug resistance. Hence, it is urgent to explore high efficiency, low toxicity, and environmental-friendly methods against S. aureus. Metal-organic frameworks (MOFs) represent great potential in treating S. aureus infection due to the unique features of MOFs including tunable chemical constitute, open crystalline structure, and high specific surface area. Especially, these properties endow MOF-based materials outstanding antibacterial effect, which can be mainly attributed to the continuously released active components and the exerted catalytic activity to fight bacterial infection. Herein, the structural characteristics of MOFs and evaluation method of antimicrobial activity are briefly summarized. Then we systematically give an overview on their recent progress on antibacterial mechanisms, metal ion sustained-release system, controlled delivery system, catalytic system, and energy conversion system based on MOF materials. Finally, suggestions and direction for future research to develop and mechanism understand MOF-based materials are discussed in antibacterial application.

Correction to “The Influence of Anions on Electron-Transfer Photochromism of Bipyridinium-Derived Metal–Organic Materials”

ADVERTISEMENT RETURN TO ISSUEPREVAdditions and Correc...Additions and CorrectionsNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to “The Influence of Anions on Electron-Transfer Photochromism of Bipyridinium-Derived Metal–Organic Materials”Jian-Jun Liu*Jian-Jun LiuMore by Jian-Jun Liuhttps://orcid.org/0000-0001-9912-5396, Shu-Biao XiaShu-Biao XiaMore by Shu-Biao Xia, Yao LiuYao LiuMore by Yao Liu, Hongbo SuoHongbo SuoMore by Hongbo Suohttps://orcid.org/0000-0002-7102-8874, Jiaming LiuJiaming LiuMore by Jiaming Liu, and Xiang ShenXiang ShenMore by Xiang Shenhttps://orcid.org/0000-0002-0736-905XCite this: Cryst. Growth Des. 2022, 22, 6, 3990Publication Date (Web):April 27, 2022Publication History Published online27 April 2022Published inissue 1 June 2022https://doi.org/10.1021/acs.cgd.2c00442Copyright © 2022 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views159Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (426 KB) Get e-AlertsSUBJECTS:Anions,Materials,Photochromism Get e-Alerts

A novel filler of biocomposites for long-term self-regulated delivery of immunomodulatory and antibacterial components to accelerate bone regeneration

Undesirable immune response and bacterial infection still remain critical challenges for the applications of biodegradable scaffolds. Herein, we assembled tannic acid (TA)/Zn2+ based metal-phenolic network complexes (MPNs) as a novel filler to render the scaffold with immunomodulatory and antibacterial functions. Besides the unique characteristics of combining the advanced functions of both TA (immunomodulation) and Zn2+ (antibacteria), another prominent feature of the filler was that it allowed to release its components in a sustainable constant rate manner, without initial burst release, lasting for more than 30 days, due to the supramolecular network structures and dynamic coordination bonds. Consequently, the modified scaffold could not only control the initial severe acute inflammation to a moderate level, but also displayed a full-course inhibition on later biodegradation-induced chronic inflammation. The manipulated anti-inflammatory micro-environment was more beneficial for in vivo osteogenesis. Additionally, the constant release rate of Zn2+ rendered the scaffold stable and long-term antibacterial performance, meanwhile avoiding cytotoxicity of Zn2+. As an emerging class of multi-functional metal-organic materials with a high degree of function modularity in terms of the choice of different metal ions and phenolic ligands, this work paved a new path for the applications of MPNs to advance multi-functional biocomposites.

Metal-organic framework firm Mosaic Materials is bought by Baker Hughes

Metal-organic framework firm Mosaic Materials is bought by Baker Hughes

Atomic/Molecular Layer Deposition for Designer's Functional Metal–Organic Materials

AbstractAtomic layer deposition (ALD) for high‐quality conformal inorganic thin films is one of the cornerstones of modern microelectronics, while molecular layer deposition (MLD) is its less‐exploited counterpart for purely organic thin films. Currently, the hybrid of these two techniques, i.e., ALD/MLD, is strongly emerging as a state‐of‐the‐art gas‐phase route for designer's metal–organic thin films, e.g., for the next‐generation energy technologies. The ALD/MLD literature comprises nearly 300 original journal papers covering most of the alkali and alkaline earth metals, 3d transition metals, and lanthanides as the metal component and a variety of aliphatic, aromatic, and natural organic components. Some of these ALD/MLD processes yield in situ crystalline coordination‐polymer‐ or metal–organic‐framework‐like structures. Another attractive aspect is that many of the metal–organics realized through ALD/MLD are fundamentally new materials, and even unaccessible through conventional synthesis. Here, the current state of research in the field is presented, by i) providing a comprehensive account of the ALD/MLD processes so far developed, ii) addressing the constraints/possibilities for growing in situ crystalline metal–organic films, iii) highlighting some intriguing ALD/MLD materials and their application potential, and iv) making a brief outlook to the future perspectives and challenges in the field.

Research progress on metal and covalent organic framework-based materials for high-performance supercapacitors

Research progress on metal and covalent organic framework-based materials for high-performance supercapacitors

Numerical study on 2-stage phase change heat sink for cooling of photovoltaic panel

Photovoltaic (PV) devices play an increasingly important role in solving the energy crisis. However, the conversion efficiency of the PV panel is small. Cooling of PV panels using phase change devices is an effective way to improve the working performance of PV panels. A phase change device with a two-level arrangement of metal-organic phase change materials (PCMs) is proposed. The PCM is filled in a metal cavity made of aluminium plates. A numerical model of the melting process of the combined PCMs is established, and the flow and heat transfer characteristics of the melting process are analysed. The results show that the temperature variation curve of the metal cavity wall close to the PV panel can be divided into three main stages according to the temperature increasing rate, i.e., the first rapidly rising stage, the slowly rising stage and the second rapidly rising stage. The temperature distribution inside the metallic cavity is more uniform compared to the temperature distribution inside the organic material cavity, and the flow in the metallic cavity is weaker, and the temperature controlling time shows a unimodal variation with the increase of gallium filling proportion in the studied ranges, and the optimal filling proportion is 56.9%.

The Chemistry of Zirconium/Carboxylate Clustering Process: Acidic Conditions to Promote Carboxylate-Unsaturated Octahedral Hexamers and Pentanuclear Species.

Clustering chemistry is a key point in the design and synthesis of the secondary building units that comprise metal-organic frameworks (MOFs) based on group IV metals. In this work, the first stages of the zirconium-carboxylate clustering process in alcohol/water mixtures are studied in detail using the monocarboxylic benzoic and hydroxybenzoic acids to avoid the polymerization. Mass spectroscopy measurements performed on the reactions revealed the presence of hexa- and pentanuclear species even at low pH values and also evidenced the acid-base nature and pH dependence of the transformation between both species. The control on the chemistry governing the equilibria between these species has allowed us to isolate six new compounds in the solid state. The single-crystal X-ray diffraction analysis revealed that they are closely related to the well-known [Zr6(O)4(OH)4(OOC)12] secondary building unit found in many MOFs by removing carboxylic ligands in the case of the hexameric species ([Zr6(O)4(OH)4(OOC)8(H2O)8]4+) or by additionally removing one of the metal centers in the case of the pentameric entities ([Zr5(O)2(OH)6(OOC)4(H2O)11(alcohol)]6+). Going in detail, the unsaturated hexameric clusters exhibit different dispositions of their eight carboxylate ligands in such a way that the remaining four carboxylate-free positions are arranged according to a square planar or tetrahedral symmetry. It should be highlighted that the pentameric complexes imply an unprecedented core nuclearity in zirconium clusters and thus their isolation provides a novel building block for the design of metal-organic materials.

Cobalt-doped UiO-66 nanoparticle as a photo-assisted Fenton-like catalyst for the degradation of rhodamine B

Metal-organic frame materials are intensively investigated in catalysis due to their outstanding thermal stability, large specific surface area, and ultra-high porosity. In this work, a cobalt-doped zirconium-based metal-organic framework, Co-UiO-66, was synthesized by the hydrothermal approach. Co-UiO-66 could successfully activate peroxymonosulfate (PMS) ions to produce reactive oxygen species for the degradation of rhodamine B (RhB) when it was used as a Fenton-like catalyst. The catalyst with 4% Co in mass in UiO-66 (4% Co-UiO-66) showed the highest degradation efficiency. About 97.3% of RhB (50 ml of 30 mg L−1) was degraded in 45 min under simulated sunlight when 10 mg of 4% Co-UiO-66 was used. The degradation efficiency was much higher than that when pure UiO-66 was used. Furthermore, it was even slightly higher than when cobalt ions were used as the activator. The single-atomic dispersion and confinement effect in Co-UiO-66, as well as the strong absorption in the visible light region are responsible for the high catalytic efficiency.

Solvo-thermal synthesis of a unique cluster-based nano-porous zinc(II) luminescent metal-organic framework for highly sensitive detection of anthrax biomarker and dichromate

In this work a flexible multi-dentate 4,4′-(1H-1,2,4-triazole-1-yl) methylene-bis(benzonic acid) (H2L) ligand has been employed, a unique cluster-based nano-porous luminescent zinc(II) metal-organic framework {[Zn(μ6-L)]·(DMAC)2}n (1) (DMAC = Dimethylacetamide) has been isolated under solvo-thermal conditions. The H2L ligand adopts hexa-dentate coordination modes via one triazole nitrogen atom and four aromatic carboxylate oxygen atoms, which bridge the neighboring six-coordinated ZnII centers, leading to a three-dimensional (3D) nano-porous metal organic framework. A PLATON program analysis suggests the total potential solvent area volume is 2028.9 Å3, which occupy 62.5% percent of the unit cell volume (3248.4 Å3). PXRD Patterns of the as-synthesized samples 1 have been determined confirming the purity of the bulky samples. Photo-luminescent properties indicate strong fluorescent emissions of 1 at the room temperature. Further photo-luminescent measurements show that 1 can exhibit highly sensitive real-time luminescence sensing of anthrax biomarker dipicolinic acid (DPA) with high quenching efficiency (KSV = 1.48 × 105 M−1) and low detection limit (0.298 μM (S/N = 3)). Meanwhile 1 also exhibits highly selective and sensitive luminescence sensing for Cr2O72- ions in aqueous solutions with high quenching efficiency KSV = 1.22 × 104 L·mol−1 and low detection limit (0.023 μM (S/N = 3)). Therefore 1 can be used a unique multi-functional 3D cluster-based metal organic material in sensitive detection and effective detection of environment pollutants and biomarker molecules.

12-Tungstophosphoric acid-encapsulated metal-organic framework UiO-66: A promising catalyst for the esterification of acetic acid with n-butanol

BackgroundThe synthesis of highly efficient and stable heteropolyacids catalysts for the esterification of acetic acid with n-butanol is an urgent task. In this work, a novel series of 12-tungstophosphoric acid-encapsulated metal-organic framework UiO-66 materials (HPW@UiO-66) with different HPW loadings were successfully prepared via a one-pot hydrothermal method. MethodsThe synthesized materials were systematically studied by FT-IR, PXRD, N2 adsorption, ICP-OES, SEM, TEM, TGA-DTG, NH3-TPD and XPS. Under the optimum reaction conditions of 120°C temperature, 2:1 n-butanol/acetic acid molar ratio, 3.0 wt% catalyst amount, and 3 h reaction time, the highest conversion of acetic acid (80.2%) was achieved over 30HPW@UiO-66. Significant findingsThe highest activity of 30HPW@UiO-66 could be attributed to its high dispersion of HPW, suitable specific surface area, total volume and total acidity. Meanwhile, the 30HPW@UiO-66 cycled to the fourth time still exhibited good catalytic activity. Moreover, an Eley-Rideal mechanism for the esterification reaction over the HPW@UiO-66 was proposed. Overall, the results demonstrated the potential of HPW@UiO-66 for the esterification process.

Strain Switching in van der Waals Heterostructures Triggered by a Spin‐Crossover Metal–Organic Framework

AbstractVan der Waals heterostructures (vdWHs) provide the possibility of engineering new materials with emergent functionalities that are not accessible in another way. These heterostructures are formed by assembling layers of different materials used as building blocks. Beyond inorganic 2D crystals, layered molecular materials remain still rather unexplored, with only few examples regarding their isolation as atomically thin layers. Here, the family of van der Waals heterostructures is enlarged by introducing a molecular building block able to produce strain: the so‐called spin‐crossover (SCO). In these metal–organic materials, a spin transition can be induced by applying external stimuli like light, temperature, pressure, or an electric field. In particular, smart vdWHs are prepared in which the electronic and optical properties of the 2D material (graphene and WSe2) are clearly switched by the strain concomitant to the spin transition. These molecular/inorganic vdWHs represent the deterministic incorporation of bistable molecular layers with other 2D crystals of interest in the emergent fields of straintronics and band engineering in low‐dimensional materials.

Preparation of Fe3O4@SW-MIL-101-NH2 for selective pre-concentration of chlorogenic acid metabolites in rat plasma, urine, and feces samples

An innovative sandwich-structural Fe-based metal-organic framework magnetic material (Fe3O4@SW-MIL-101-NH2) was fabricated using a facile solvothermal method. The characteristic properties of the material were investigated by field emission scanning electron microscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray powder diffraction, vibrating sample magnetometry, and Brunauer-Emmett-Teller measurements. Fe3O4@SW-MIL-101-NH2 is associated with advantages, such as robust magnetic properties, high specific surface area, and satisfactory storage stability, as well as good selective recognition ability for chlorogenic acid (CA) and its metabolites via chelation, hydrogen bonding, and π-interaction. The results of the static adsorption experiment indicated that Fe3O4@SW-MIL-101-NH2 possessed a high adsorption capacity toward CA and its isomers, cryptochlorogenic acid (CCA) and neochlorogenic acid (NCA), and the adsorption behaviors were fitted using the Langmuir adsorption isotherm model. Then, a strategy using magnetic solid-phase extraction (MSPE) and ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF MS/MS) was developed and successfully employed for the selective pre-concentration and rapid identification of CA metabolites in rat plasma, urine, and feces samples. This work presents a prospective strategy for the synthesis of magnetic adsorbents and the high-efficiency pretreatment of CA metabolites.

Metal organic framework-based nanostructure materials: applications for non-lithium ion battery electrodes

Non-lithium ion (e.g., Al3+, Ca2+, K+, Mg2+, Na+, and Zn2+) batteries have emerged as a promising platform for next-generation energy storage systems.

Synthesis of Metal-Organic Frame Material MOF-5 and Testing of Its Dye Adsorption Properties

Synthesis of Metal-Organic Frame Material MOF-5 and Testing of Its Dye Adsorption Properties

Low-temperature ALD/MLD growth of alucone and zincone thin films from non-pyrophoric precursors.

The combined atomic/molecular layer deposition (ALD/MLD) technique is emerging as a state-of-the-art synthesis route for new metal-organic thin-film materials with a multitude of properties by combining those of the inorganic and the organic material. A major part of the studies so far reported have focused on aluminum or zinc alkyls, so-called alucone and zincone films, typically grown from trimethyl aluminum (TMA) or diethyl zinc (DEZ) as the metal-bearing precursor, and a simple aliphatic bi-functional alcohol molecule such as ethylene glycol (EG) as the organic precursor. However, these common precursors possess certain disadvantages: both TMA and DEZ are pyrophoric, DEZ being additionally thermally unstable, while EG has a strong tendency for various unideal reaction modes. Here we report novel ALD/MLD processes for alucone and zincone films based on non-pyrophoric bis-diisopropylamido-[3-(N,N-dimethylamino)propyl] aluminum(III) [Al(NiPr2)2(DMP)] and bis-3-(N,N-dimethylamino)propyl zinc(II) [Zn(DMP)2] precursors in combination with hydroquinone (HQ) as the organic precursor. We demonstrate that the [Al(NiPr2)2(DMP)] + HQ and [Zn(DMP)2] + HQ ALD/MLD processes work even at record low deposition temperatures (140 °C and 60 °C, respectively) yielding high-quality and relatively stable Al-HQ and Zn-HQ thin films with appreciably high growth rates (2.8 Å / cycle and 3.2 Å / cycle, respectively). Moreover, these ALD/MLD processes are compatible with the corresponding ALD processes, i.e. [Al(NiPr2)2(DMP)] + H2O and [Zn(DMP)2] + H2O, for the Al2O3 and ZnO films, thus opening up new horizons for the fabrication of novel metal-oxide : organic superlattice structures for e.g. flexible gas-barrier coatings or wearable thermoelectrics.

Hierarchical porous metal-organic gels and derived materials: from fundamentals to potential applications.

Metal-organic gels (MOGs) emerged as a novel class of functional soft materials in which the scaffolding framework is fabricated by metal-ligand coordination in combination with other supramolecular interactions (for example, hydrogen bonding or π-π stacking). Through the combination of organic and inorganic (metal/metal-oxo clusters) building blocks, significant steps forward have been made in the development of new electrochemical sensors, superhydrophobic materials and ion storage devices, among others. These leaps forward are to some extend induced by the intrinsic hierarchical microporous/mesoporous pore structure of these metal-organic materials. Within this review we give an overview of recent developments of this growing field. First, we shed light onto the parallels to the well-established field of conventional gels and outline similarities and differences. Afterwards, we classify different types of MOGs according to their architectural/structural nature: (1) pristine MOGs, (2) hybrid MOGs, (3) crosslinking-based MOGs and (4) MOG-derived materials. Furthermore, we look at the different properties of MOGs and the requirements for the preparation of spatially patterned macro-structured MOGs by emerging additive manufacturing technologies. Moreover, different potential fields of application for MOGs and MOG derived materials are critically evaluated and potential improvements and pitfalls in comparison to traditional gel-based materials are given. Finally, a comprehensive outlook into future directions for the development of MOGs is provided.

A Cu-BTC material encapsulated by chemical chromophore 1,3,6,8-tetrakis (p-benzoic acid) pyrene: Fluorescent sensing in recognition of the different ions

A kind of metal organic framework composite material was prepared by encapsulating chemical chromophore the 1,3,6,8-tetrakis(p-benzoic acid)pyrene (H4TBAPy) in Cu-BTC which has the large square-shaped pores, a reasonable degree of thermal stability and a capacity for chemical functionalization of the channel linings. Cu-BTC@H4TBAPy has superior luminescence performance than framework material Cu-BTC (H3BTC = 1, 3, 5-trimellitic acid). Base on its luminescence property, we performed fluorescence sensing experiments on heavy metal ions. The results show that the metal ion Fe3+ has a significant turn-off effect on Cu-BTC@H4TBAPy, while Al3+ has a significant turn-on effect on Cu-BTC@H4TBAPy. This indicates that Cu-BTC@H4TBAPy can play a role of fluorescent sensor switch in recognition of different ions.