Isostructural Synthesis of Porous Metal–Organic Nanotubes

Murdock, Christopher R.; Jenkins, David M.

doi:10.1021/ja5042226

Cited by 70 publications

(70 citation statements)

References 67 publications

(95 reference statements)

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“…Uncoordinated SO 4 2− ions are aligned along the c ‐axis within the pore channels (Figure b; Figure S5–S8). It is noteworthy that although metal–sulfate‐based open frameworks are well known,– coordination polymers having free sulfate ions are uncommon– and structures containing both free and ligated SO 4 2− ions, as in the present case, are even rarer –. Powder X‐ray diffraction (PXRD) patterns (Figure S9) and elemental analysis confirmed the bulk phase purity of the compound.…”

Section: Methodssupporting

confidence: 58%

A Water‐Stable Cationic Metal–Organic Framework as a Dual Adsorbent of Oxoanion Pollutants

et al. 2016

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At hree-dimensional water-stable cationic metalorganic framework (MOF) pillared by an eutral ligand and with Ni II metal nodes has been synthesized employing arational design approach. Owing to the ordered arrangement of the uncoordinated tetrahedral sulfate (SO 4 2À )i ons in the channels,the compound has been employed for aqueous-phase ion-exchange applications.T he compound exhibits rapid and colorimetric aqueous-phase capture of environmentally toxic oxoanions (with similar geometries) in aselective manner.This system is the first example of aM OF-based system which absorbs both dichromate (Cr 2 O 7 2À )a nd permanganate (MnO 4 À )i ons,w ith the latter acting as am odel for the radioactive contaminant pertechnetate (TcO 4 À ).Water pollution has become ap ressing global concern and the sequestration of toxic contaminants present in water streams has attracted significant research attention. In particular,t he widespread growth of modern industry has meant that the segregation of heavy-metal contaminants from industrial effluents has become apertinent problem.[1] Several inorganic pollutants,present in the form of oxoanions,feature prominently in the list from the Environment Protection Agency (EPA) of priority pollutants.[2] Attempts have been made to capture and remove these species from water streams through the development of materials and/or methods for selective entrapment. In particular,m uch research has focused on the separation of Cr VI ions,g enerated, for example,f rom chromium plating,p igment synthesis,a nd leather tanning,because of the severe health hazards posed by its predominant ionic form.[3] Similarly,t he presence of pertechnetate (TcO 4 À )i ons in radioactive waste vitrification poses serious disposal issues because of the long half-life and facile mobility of the ions.[4] Although several techniques, such as ion exchange,a dsorption, and photocatalytic reduction, have been trialed for this purpose, [5] in general the preferred routes have applied ion-exchange pathways owing to cost, sensitivity,simplicity,and selectivity considerations. [6] Thel imitations of the currently employed ion exchangers, such as slow process kinetics and poor selectivity,actuates the development of newer materials or optimization of the performance of the currently studied adsorbents.Metal-organic frameworks (MOFs), built from organic linkers and metal ions,have evolved as an important class of porous materials. [7] Thefact that the pore size and surface of MOFs can be easily tuned renders these compounds suitable for selective sorption and separation applications.[8] As asubclass,cationic MOFs have attracted significant attention as anion receptors/separators because of the confinement of substitutable uncoordinated anionic species.[9] Generally,such frameworks are fabricated from neutral N-donor ligands wherein the residual charge-balancing ions reside in the void spaces.[10] Although porous cationic materials,i ncluding MOFs,h ave been explored for several applications as anion-exchange h...

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Section: Methodssupporting

confidence: 58%

A Water‐Stable Cationic Metal–Organic Framework as a Dual Adsorbent of Oxoanion Pollutants

et al. 2016

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“…The preparation of single‐walled metal‐organic nanotubes is an emerging area of research interest because of alluring potential applications in gas storage and separation, sensing, catalysis, environmental remediation, or conductive materials technology . Even though the fabrication of such architectures is fraught with inherent challenges due to the fickle nature of self‐assembly, several successful strategies have been employed to produce tubular systems , . One promising strategy is to decorate metallacycles with groups capable of participating in hydrogen‐bonding interactions (either charge‐assisted or not) to enforce cofacial stacking of rings .…”

Section: Introductionmentioning

confidence: 99%

Supramolecular Assembly of Metal‐Organic Tubes Constructed from the Ditopic Heteroscorpionate Ligand (4‐NH2C6H4)CHpz2 (pz = Pyrazol‐1‐yl) and Silver(I)

et al. 2015

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The possibility of constructing tubular metal-organic structures with aid of weak hydrogen-bonding interactions between suitably designed metallacycles was explored. For this purpose, the new heteroditopic ligand (4-NH 2 C 6 H 4 )CHpz 2 (L1) was prepared in good (75 %) yield by a one-pot procedure starting from commercial 4-acetamidobenzaldehyde. The equimolar reactions between L1 and various silver(I) salts gave the intended 1:1 complexes in which the metallacycles were assembled into tubes. However, the exact nature of the assem- [a] Scheme 1. Some heteroditopic heteroscorpionate ligands (top) and a sampling of supramolecular isomers formed after metal coordination (bottom). Results and Discussion SynthesisThe new ligand (4-H 2 NC 6 H 4 )CHpz 2 (L1) was prepared by two different routes, as summarized in Scheme 2. Of the two pathways, Method A (Scheme 2, top) is preferred, because a 75 % yield can be obtained after a one-pot, two-step reaction sequence starting from commercial and inexpensive reagents. The yield of the CoCl 2 -catalyzed Peterson rearrangement [16] between the aldehyde and S(O)pz 2 was improved by 10-20 % by using an excess of S(O)pz 2 (relative to cases in which a 1:1 stoichiometric ratio of reagents was used). It is also noted that the rate of hydrolysis of the intermediate, {4-[CH 3 C(O)NH]C 6 H 4 }-CHpz 2 , is greatly enhanced in aqueous solution with respect to in solvent mixtures (THF/water or methanol/water). That is, after monitoring of the amide deprotection reaction by TLC, the rate of hydrolysis was observed to increase with water content of the solvent mixture. The deprotection reaction did not proceed to any appreciable extent when mixtures of NaOH (or KOH) and the intermediate were heated at reflux in dry MeOH over the course of a day, but the reaction was complete within hours when only water was used as a solvent. The ligand has significant solubility in water and in basic solution; this slightly complicates its extraction into organic solvents. That is, yields can be artificially low if care is not taken to ensure complete extraction by using numerous aliquots of organic solvent (ethyl acetate was particularly effective) and by checking the aqueous layer for product by TLC.

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“…[12] Owing to their convenient tunability both in composition and topology,M ONTs have recently become atopic of vigorous research. [13] Coordination-driven self-assembly has been proven to be ap owerful approach in the bottom-up construction of designable supramolecular architectures. [14] Numerous macrocyclic, polyhedral, and spherical structures have been designed with various types of organic ligands and metal ions based on elaborate symmetry considerations.…”

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confidence: 99%

Bottom‐Up Construction of Mesoporous Nanotubes from 78‐Component Self‐Assembled Nanobarrels

et al. 2015

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Segmental and continuous hexagonal-packed mesoporous metal-organic nanotubes (MMONTs) with outside diameters of up to 4.5 nm and channel sizes of 2.4 nm were hierarchically constructed by a rational multicomponent self-assembly process involving starting from [L2Pd2(NO3)2] (L=o-phenanthroline or 2,2'-bipyridine) and 4-pyridinyl-3-pyrazole. An unprecedented crystallization-driven cross-linking between discrete nanobarrel building units by spontaneous loss of the capping ligands to form infinite nanotubes was observed. Such a barrel-to-tube transformation provides new possibilities for the fabrication of MMONTs using the solution bottom-up approach.

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Isostructural Synthesis of Porous Metal–Organic Nanotubes

Cited by 70 publications

References 67 publications

A Water‐Stable Cationic Metal–Organic Framework as a Dual Adsorbent of Oxoanion Pollutants

A Water‐Stable Cationic Metal–Organic Framework as a Dual Adsorbent of Oxoanion Pollutants

Supramolecular Assembly of Metal‐Organic Tubes Constructed from the Ditopic Heteroscorpionate Ligand (4‐NH2C6H4)CHpz2 (pz = Pyrazol‐1‐yl) and Silver(I)

Bottom‐Up Construction of Mesoporous Nanotubes from 78‐Component Self‐Assembled Nanobarrels

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