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James Wainaina Maina, Jurg Schutz, Luke Grundy, Elise Des Ligneris, Zhifeng Yi, Lingxue Kong, Cristina Pozo-Gonzalo, Mihail Ionescu, Ludovic F Dumée
Photocatalytic conversion of carbon dioxide (CO2) to useful products has potential to address the adverse environmental impact of global warming. However, most photocatalysts used to date exhibit limited catalytic performance, due to poor CO2 adsorption capacity, inability to efficiently generate photoexcited electrons, and/or poor transfer of the photo-generated electrons to CO2 molecules adsorbed on the catalyst surface. The integration of inorganic semiconductor nanoparticles across metal organic framework (MOF) materials has potential to yield new hybrid materials, combining high CO2 adsorption capacity of MOF and the ability of the semiconductor nanoparticles to generate photoexcited electrons...
September 22, 2017: ACS Applied Materials & Interfaces
Amarajothi Dhakshinamoorthy, Abdullah M Asiri, Hermenegildo Garcia
Selective benzyl alcohol oxidation (BA) to benzaldehyde has been frequently used as a benchmark reaction to evaluate the catalytic activity of metal organic frameworks (MOFs) as oxidation catalysts. Substituted BAs, and aliphatic and allylic alcohols have also been often used as substrates in these studies. In the present review, the current state of the art of MOFs as heterogeneous catalysts for the oxidation of BA and other alcohols is described, grouping the reports according to the nature of the active sites present on the MOFs...
September 22, 2017: Chemical Communications: Chem Comm
Mali H Rosnes, Denis Sheptyakov, Alexandra Franz, Matthias Frontzek, Pascal D C Dietzel, Peter A Georgiev
Using gas sorption measurements at ambient temperatures and in situ neutron powder diffraction methods, we have studied the interaction strengths and coordination geometries of O2 and N2 near the non-occupied coordination site (open metal site) in the isostructural MOF structures of the CPO-27-M/M-MOF-74 series (with M = Co, Ni, Mn and Cu). Our experimental observations are compared to periodic quantum chemical model calculations. Contrary to recent computational studies, our results, both experimental and theoretical, unequivocally suggest rather weak interactions between the M(ii) coordinatively unsaturated centers and the adsorbate molecules, being mainly dispersive and electrostatic in nature...
September 22, 2017: Physical Chemistry Chemical Physics: PCCP
Rajenahally V Jagadeesh, Kathiravan Murugesan, Ahmad S Alshammari, Helfried Neumann, Marga-Martina Pohl, Jörg Radnik, Matthias Beller
The development of base metal catalysts for the synthesis of pharmaceutically relevant compounds remains an important goal of chemical research. Here, we report that cobalt nanoparticles encapsulated by a graphitic shell are broadly effective reductive amination catalysts. Their convenient and practical preparation entailed template assembly of cobalt-diamine-dicarboxylic acid metal organic frameworks on carbon and subsequent pyrolysis under inert atmosphere. The resulting stable and reusable catalysts were active for synthesis of primary, secondary, tertiary and N-methylamines (>140 examples)...
September 21, 2017: Science
Danping Chen, Ran Luo, Meiyan Li, Mengqi Wen, Yan Li, Chao Chen, Ning Zhang
Herein, a new preparation strategy of chiral metal-organic frameworks (CMOFs) has been demonstrated. By adsorption and then post-synthetically modified (PSM) procedures, chiral salen(Co(iii)) could be imprisoned within the cages of an MOF and remained in its free form. This is the first report on the successful application of CMOFs in heterogeneous asymmetric catalysis for coupling CO2 with epoxides to obtain optically active cyclic carbonates at room temperature.
September 21, 2017: Chemical Communications: Chem Comm
Zhujun Zhang, Shiliang Zhang, Qilu Yao, Xiangshu Chen, Zhang-Hui Lu
The catalytic dehydrogenation of hydrazine borane (N2H4BH3) and hydrous hydrazine (N2H4·H2O) for H2 evolution is considered as two of the pivotal reactions for the implementation of the hydrogen-based economy. A reduction rate controlled strategy is successfully applied for the encapsulating of uniform tiny NiPt alloy nanoclusters within the opening porous channels of MOFs in this work. The resultant Ni0.9Pt0.1/MOF core-shell composite with a low Pt content exerted exceedingly high activity and durability for complete H2 evolution (100% hydrogen selectivity) from alkaline N2H4BH3 and N2H4·H2O solution...
September 20, 2017: Inorganic Chemistry
Martino Rimoldi, Joseph T Hupp, Omar K Farha
Methyltrioxorhenium (ReO3Me) is introduced as the first rhenium atomic layer deposition (ALD) precursor and used to grow rhenium aluminum oxide thin films in combination with trimethylaluminum (TMA - AlMe3). The growth rate of the smooth Re-Al oxide films, with general stoichiometry RexAlyO3x, has been monitored by in situ quartz crystal microbalance (QCM) and ex situ ellipsometry, and found to be 3.2 Å/cycle. X-ray photoelectron spectroscopy (XPS) revealed the mixed valent composition of the film with Re(III) species being the main component...
September 20, 2017: ACS Applied Materials & Interfaces
Zhiliang Jin, Hao Yang
The application of metal-organic framework (MOF) in the field of photocatalysis is limited, because of its unstable chemical properties and failure to respond in visible light. Herein, the Pd/MOF catalysts were prepared by impregnation reduction. It is important that we have reasonably constructed the dye-sensitized system of Pd/MOF and successfully extended the application of MOF to the visible range. It exhibited maximal photocatalytic activity (9.43 mmol/g) under visible-light irradiation (λ ≥ 420 nm) with eosin Y as a photo-sensitizer, which was enhanced twice the order of magnitude compared with the pure MOF (0...
September 19, 2017: Nanoscale Research Letters
Dongdong Zhu, Chunxian Guo, Jinlong Liu, Liang Wang, Yi Du, Shi-Zhang Qiao
A two-dimensional metal-organic framework (MOF) comprising nickel species and an organic ligand of benzenedicarboxylic acid is fabricated and explored as an electrocatalyst for urea oxidation reaction (UOR). The excellent UOR performance is found to be partially due to the high active site density of the two-dimensional MOF, and largely because of the high oxidation state of the nickel species.
September 20, 2017: Chemical Communications: Chem Comm
Martijn C de Koning, Marco van Grol, Troy Breijaert
In recent years, Zr-based metal-organic frameworks (MOFs) have been developed that facilitate catalytic degradation of toxic organophosphate agents, such as chemical warfare agents (CWAs). Because of strict regulations, experiments using live agents are not possible for most laboratories and, as a result, simulants are used in the majority of cases. Reports that employ real CWAs are scarce and do not cover the whole spectrum of agents. We here present a comparative study in which UiO-66-NH2, NU-1000, MOF-808, and PCN-777 are evaluated for their effectiveness in the degradation of paraoxon and the chemical warfare agents tabun, VX, and soman, in N-ethylmorpholine buffer (pH 10) as well as in pure water...
September 19, 2017: Inorganic Chemistry
Yangke Long, Ling Xiao, Qihua Cao, Xiaowen Shi, Yunan Wang
Metal phenolic networks (MPNs) were used for the first time for the construction of core@shell MOF materials. Diverse functional nanocores with different shapes and sizes could be coated with ZIF-8 shells mediated by MPNs. The obtained Fe3O4@TA-Fe(3+)@ZIF-8 powder showed a superhydrophobic nature which could efficiently absorb n-hexane from water.
September 19, 2017: Chemical Communications: Chem Comm
Bo-Wen Sun, Hong-Yu Yu, Yong-Jing Yang, Hui-Jun Li, Cheng-Yu Zhai, Dong-Jin Qian, Meng Chen
To date, there have been only a few studies focusing on the assignment of X-ray diffraction (XRD) patterns in graphitic carbon nitrides (g-C3N4) and contradictory determination for a broad peak around 12°-14° has been perplexing. In this study, assignments are carried out both theoretically and experimentally. The cell parameters for g-C3N4 are determined as a = b = 8.1 Å, c = 6.5 Å, α = β = 90°, and γ = 120°. Qualitative and semi-quantitative methods such as fast Fourier transform and residual after 1st and 2nd derivatives are used to confirm and search the hidden peaks...
September 19, 2017: Physical Chemistry Chemical Physics: PCCP
Jingquan Sha, Peipei Zhu, Xiya Yang, Xueni Li, Xiao Li, Mingbo Yue, Kunfeng Zhou
A POMs templated 3D Ag-carbene framework with lvt-a topology was hydrothermally synthesized. The POMs templated MCF combining the advantages of POMs, MOFs, and carbene not only shows excellent thermal and chemical stabilities but also possesses a good discharge capacity of 481 mAh·g(-1) after 100 cycles applied as anode material in LIBs.
September 19, 2017: Inorganic Chemistry
C M Nagaraja, Sandeep Dhankhar, Nayuesh Sharma, Sandeep Kumar, Dhilip Kumar
A bifunctional, microporous Zn(II) metal-organic framework, [Zn2(NH2BDC)2(dpNDI)]n (MOF1) (where, NH2BDC =2-aminoterephthalic acid, dpNDI =N,N'-di(4-pyridyl)-1,4,5,8-naphthalenediimide) has been synthesized solvothermally. MOF1 shows a 2-fold interpenetrated, 3D pillar-layered framework structure composed of two types of 1D channels with dimensions of ~3.80 x 16.9 Å2 and 7.49 x 17.01 Å2 decorated with pendent -NH2 group. Owing to the presence of basic functionalized pore surface, MOF1 exhibits selective adsorption of CO2 with high value of heat of adsorption (Qst = 46...
September 19, 2017: Chemistry: a European Journal
Claudia Orellana-Tavra, Salame Haddad, Ross J Marshall, Isabel Abanades Lazaro, Gerard Boix, Inhar Imaz, Daniel Maspoch, Ross S Forgan, David Fairen-Jimenez
A critical bottleneck for the use of metal-organic frameworks (MOFs) as drug delivery systems has been allowing them to reach their intracellular targets without being degraded in the acidic environment of the lysosomes. Cells take up particles by endocytosis through multiple biochemical pathways, and the fate of these particles depends on these routes of entry. Here, we show the effect of functional group incorporation into a series of Zr-based MOFs on their endocytosis mechanisms, allowing us to design an effi-cient drug delivery system...
September 19, 2017: ACS Applied Materials & Interfaces
Baptiste Laramée-Milette, Francesco Nastasi, Fausto Puntoriero, Sebastiano Campagna, Garry S Hanan
Self-assembly is a powerful synthetic tool that has led to the development of one-, two- and three-dimensional architectures. From MOFs to molecular flasks, self-assembled materials have proven to be of great interest to the scientific community. Here we describe a strategy for the construction and de-construction of a supramolecular structure through unprecedented photo-induced assembly and dis-assembly. The combination of two approaches, a [n×1]-directional bonding strategy and a ligand photo-dissociation strategy, allows the photo-induced assembly of a polypyridyl Ru(II) precursor into a discrete molecular square...
September 18, 2017: Chemistry: a European Journal
Soutick Nandi, Helge Reinsch, Sooram Banesh, Norbert Stock, Vishal Trivedi, Shyam Biswas
A new, azide-functionalized Al(iii)-based metal-organic framework (MOF) denoted as CAU-10-N3 (1, CAU = Christian-Albrechts-University) and consisting of the 5-azido-isophthalic acid (H2IPA-N3) ligand was employed as a reaction-based fluorescent turn-on probe for the detection of H2S. The activated compound (1') showed fast, selective and highly sensitive sensing properties for extracellular H2S in HEPES buffer (10 mM, pH = 7.4). The material retained its high selectivity even in the presence of possibly competing biological species...
September 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Gan Ye, Dan Zhang, Xiangfu Li, Kunyue Leng, Wenjuan Zhang, Jun Ma, Yinyong Sun, Wei Xu, Shengqian Ma
The control of defects in crystalline materials has long been of significance since the defects are correlated with the performances of the materials. Yet such control remains a challenge for metal-organic frameworks (MOFs), which are usually well crystallized under hydro/solvo-thermal conditions. In this contribution, we demonstrate for the first time how to increase the defects of MOF via a facile and green approach as exemplified in the context of solvent-free synthesis of UiO-66(Zr). Such increase of defects leads to drastic enhancement of catalysis performance when compared to UiO-66(Zr) prepared from conventional hydro/solvo-thermal synthesis...
September 18, 2017: ACS Applied Materials & Interfaces
Hao Chen, Min Qiang Wang, Yanan Yu, Heng Liu, Shi-Yu Lu, Shu-Juan Bao, Maowen Xu
Metal-origanic frameworks (MOF)-derived hollow cobalt sulfides have attracted extensive attention due to their porous shell that provides rich redox reactions for energy storage. However, their ultra-dispersed structure and large size of MOFs precursors result in relatively low conductivity, stability, and low tap density .Therefore, the construction of an array of continuous hollow cages and tailor the inner cavity of MOF-derived materials is very effective for enhancing the electrochemical performance. Herein, we in situ assembled small Co-based zeolitic imidazolate framework (ZIF-67) on the both sides of negatively charged MnO2 nanosheets to fabricate a hierarchical sandwich-type composite with hollow cobalt sulfide nanocages/graphene-like MnO2...
September 18, 2017: ACS Applied Materials & Interfaces
Zhiye Wang, Zi Wang, Bangjiang Lin, Xuefu Hu, YunFeng Wei, Cankun Zhang, Bing An, Cheng Wang, Wenbin Lin
A dye@metal-organic framework (MOF) hybrid was used as a phosphor in a white light emitting diode (WLED) for fast visible-light communication (VLC). The white light was generated from a combination of blue emission of the 9,10-dibenzoate anthracene (DBA) linkers and yellow emission of the encapsulated Rhodamine B molecules. The MOF structure not only prevents dye molecules from aggregation-induced quenching, but also efficiently transfers energy to the dye for dual emission. This light-emitting material shows emission lifetimes of 1...
September 18, 2017: ACS Applied Materials & Interfaces
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