217077-89-9Relevant academic research and scientific papers
Tailoring the Optical Absorption of Water-Stable ZrIV- and HfIV-Based Metal-Organic Framework Photocatalysts
Doan, Tan L. H.,Nguyen, Ha L.,Pham, Hung Q.,Pham-Tran, Nguyen-Nguyen,Le, Thach N.,Cordova, Kyle E.
, p. 2660 - 2668 (2015)
New ZrIV- and HfIV-based metal-organic framework photocatalysts, termed VNU-1 and VNU-2 (where VNU=Vietnam National University), were synthesized and their resulting structures fully characterized. By employing a highly π-conjugated
Functional Versatility of a Series of Zr Metal-Organic Frameworks Probed by Solid-State Photoluminescence Spectroscopy
Marshall, Ross J.,Kalinovskyy, Yaroslav,Griffin, Sarah L.,Wilson, Claire,Blight, Barry A.,Forgan, Ross S.
supporting information, p. 6253 - 6260 (2017/05/09)
Many of the desirable properties of metal-organic frameworks (MOFs) can be tuned by chemical functionalization of the organic ligands that connect their metal clusters into multidimensional network solids. When these linker molecules are intrinsically fluorescent, they can pass on this property to the resultant MOF, potentially generating solid-state sensors, as analytes can be bound within their porous interiors. Herein, we report the synthesis of a series of 14 interpenetrated Zr and Hf MOFs linked by functionalized 4,4′-[1,4-phenylene-bis(ethyne-2,1-diyl)]-dibenzoate (peb2-) ligands, and we analyze the effect of functional group incorporation on their structures and properties. Addition of methyl, fluoro, naphthyl, and benzothiadiazolyl units does not affect the underlying topology, but induces subtle structural changes, such as ligand rotation, and mediates host-guest interactions. Further, we demonstrate that solid-state photoluminescence spectroscopy can be used to probe these effects. For instance, introduction of naphthyl and benzothiadiazolyl units yields MOFs that can act as stable fluorescent water sensors, a dimethyl modified MOF exhibits a temperature dependent phase change controlled by steric clashes between interpenetrated nets, and a tetrafluorinated analogue is found to be superhydrophobic despite only partial fluorination of its organic backbone. These subtle changes in ligand structure coupled with the consistent framework topology give rise to a series of MOFs with a remarkable range of physical properties that are not observed with the ligands alone.
Stereoselective Halogenation of Integral Unsaturated C-C Bonds in Chemically and Mechanically Robust Zr and Hf MOFs
Marshall, Ross J.,Griffin, Sarah L.,Wilson, Claire,Forgan, Ross S.
supporting information, p. 4870 - 4877 (2016/04/05)
Metal-organic frameworks (MOFs) containing ZrIV-based secondary building units (SBUs), as in the UiO-66 series, are receiving widespread research interest due to their enhanced chemical and mechanical stabilities. We report the synthesis and extensive characterisation, as both bulk microcrystalline and single crystal forms, of extended UiO-66 (Zr and Hf) series MOFs containing integral unsaturated alkene, alkyne and butadiyne units, which serve as reactive sites for postsynthetic modification (PSM) by halogenation. The water stability of a Zr-stilbene MOF allows the dual insertion of both -OH and -Br groups in a single, aqueous bromohydrination step. Quantitative bromination of alkyne- A nd butadiyne-containing MOFs is demonstrated to be stereoselective, as a consequence of the linker geometry when bound in the MOFs, while the inherent change in hybridisation and geometry of integral linker atoms is facilitated by the high mechanical stabilities of the MOFs, allowing bromination to be characterised in a single-crystal to single-crystal (SCSC) manner. The facile addition of bromine across the unsaturated C-C bonds in the MOFs in solution is extended to irreversible iodine sequestration in the vapour phase. A large-pore interpenetrated Zr MOF demonstrates an I2 storage capacity of 279 % w/w, through a combination of chemisorption and physisorption, which is comparable to the highest reported capacities of benchmark iodine storage materials for radioactive I2 sequestration. We expect this facile PSM process to not only allow trapping of toxic vapours, but also modulate the mechanical properties of the MOFs.
An efficient combination of Zr-MOF and microwave irradiation in catalytic Lewis acid Friedel-Crafts benzoylation
Doan, Tan L. H.,Dao, Thong Q.,Tran, Hai N.,Tran, Phuong H.,Le, Thach N.
, p. 7875 - 7880 (2016/05/24)
A zirconium-based metal-organic framework, an effective heterogeneous catalyst, has been developed for the Friedel-Crafts benzoylation of aromatic compounds under microwave irradiation. Constructed by a Zr(iv) cluster and a linker 1,4-bis(2-[4-carboxyphenyl]ethynyl)benzene (H2CPEB), the MOF, possessing large pores and high chemical stability, was appropriate for the enhancement of Lewis acid activity under microwave irradiation. The reaction studies demonstrated that the material could give high yields for a few minutes and maintain its reactivity and structure over several cycles.
Controlling the structural and electrical properties of diacid oligo(phenylene ethynylene) langmuir-blodgett films
Ballesteros, Luz Marina,Martin, Santiago,Cortes, Javier,Marques-Gonzalez, Santiago,Higgins, Simon J.,Nichols, Richard J.,Low, Paul J.,Cea, Pilar
, p. 5352 - 5363 (2013/05/09)
The preparation, characterization and electrical properties of Langmuir-Blodgett (LB) films composed of a symmetrically substituted oligomeric phenylene ethynylene derivative, namely, 4,4′-[1,4-phenylenebis(ethyne-2, 1-diyl)]dibenzoic acid (OPE2A), are de
Delocalization of free electron density through phenylene-ethynylene: Structural changes studied by time-resolved infrared spectroscopy
Polyansky, Dmitry E.,Danilov, Evgeny O.,Voskresensky, Sergey V.,Rodgers, Michael A. J.,Neckers, Douglas C.
, p. 13452 - 13453 (2007/10/03)
We have studied the photochemistry of 1,4-bis(2-[4-tert-butylperoxycarbonylphenyl]ethynyl)benzene (1) and tert-butyl 4-(2-{4-[2-(4-phenyloxycarbonylphenyl)-1-ethynyl]phenyl}-1-ethynyl)peroxybenzoate (2). Excitation of 1 and 2 by a 355-nm laser pulse leads to the rapid formation of aroyloxyl radicals. An unpaired electron conjugated with the phenylene-ethynylene core is substantially delocalized over the π-system of the chromophore. The -C≡C- vibrational frequencies of these radicals are red-shifted relative to 1 and 2 as measured by time-resolved IR spectroscopy. This shift is attributed to the change in the triple bond character due to delocalization of the free electron. Copyright
Synthesis, optical properties, crystal structures and phase behaviour of symmetric, conjugated ethynylarene-based rigid rods with terminal carboxylate groups
Fasina, Tolulope M.,Collings, Jonathan C.,Burke, Jacqueline M.,Batsanov, Andrei S.,Ward, Richard M.,Albesa-Jove, David,Porres, Laurent,Beeby, Andrew,Howard, Judith A. K.,Scott, Andrew J.,Clegg, William,Watt, Stephen W.,Viney, Christopher,Marder, Todd B.
, p. 690 - 697 (2007/10/03)
Sonogashira cross-coupling reactions of 4-ethynylmethylbenzoate (1) with aryl halides gave 1,2-bis(4-carbomethoxyphenyl)ethyne (2), 1,4-bis(4- carbomethoxyphenylethynyl)benzene (3), 1,4-bis(4-carbomethoxyphenylethynyl) tetrafluorobenzene (4) and 9,10-bis(4-carbomethoxyphenylethynyl)anthracene (5), protected precursors to conjugated rigid rod bis(carboxylato) ligands. The compound 1,4-bis(4-carbomethoxyphenyl)butadiyne (6) was prepared by the oxidative homo-coupling of 1. The hydrolysis of 2 and 3 by NaOH in methanol gave the sodium salts of the respective carboxylate anions and subsequent treatment with HCl gave the corresponding free carboxylic acids. Compounds 2-6 were characterised by absorption, emission, IR, NMR and mass spectrometry and examined for liquid crystal phase behaviour by differential thermal analysis (DTA) and transmitted polarised light microscopy (TPLM). Compound 4 exhibited a nematic phase stable from 233.6 °C until decomposition at 320 °C. The single-crystal structures of 2, 5 and 6 were determined by X-ray diffraction at 110-160 K. The Royal Society of Chemistry 2005.
