Macrocycle-metal cation interactions involving polyaza macrocycles bonded to silica gel via a nitrogen donor atom

Izatt, Reed M.; Bruening, Ronald L.; Tarbet, Bryon J.; Griffin, L. David; Bruening, Merlin L.; Krakowiak, Krzysztof E.; Bradshaw, Jerald S.

doi:10.1351/pac199062061115

Cited by 35 publications

(17 citation statements)

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“…The structural design aspects of crown ethers are decidedly simple, wherein ring‐size and chirality can be controlled from the number of ethylene oxide subunits. Moreover, the chemistry of crown ethers is rich; aza‐ and thia‐crowns are well known, as well as mixtures thereof and also metallacrowns in which metal cations are part of the ring structure have been studied . Indeed, crown ethers can also be derived from other subunits, such as catechol‐type ligands, or be functionalized with side‐chains or “lariats” to afford better host–guest interactions …”

Section: Molecular Fillers and Polymers In MMCMmentioning

confidence: 99%

Molecularly Mixed Composite Membranes: Challenges and Opportunities

Zhu

O’Nolan

Lively

2019

Chemistry A European J

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The fabrication of porous molecules, such as metal–organic polyhedra (MOPs), porous organic cages (POCs) and others, has given rise to the potential for creating “solid solutions” of molecular fillers and polymers. Such solid solutions circumvent longstanding interface issues associated with mixed matrix membranes (MMMs), and are referred to as molecularly mixed composite membranes (MMCMs) to distinguish them from traditional two‐phase MMMs. Early investigations of MMCMs highlight the advantages of solid solutions over MMMs, including dispersion of the filler, anti‐plasticization of the polymer network, and removal of deleterious interfacial issues. However, the exact microscopic structure as well as the transport modality in this new class of membrane are not well understood. Moreover, there are clear engineering challenges that need to be addressed for MMCMs to transition into the field. In this Minireview, the authors outline several scientific and technological challenges associated with the aforementioned questions and their suggestions to tackle them.

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Section: Molecular Fillers and Polymers In MMCMmentioning

confidence: 99%

Molecularly Mixed Composite Membranes: Challenges and Opportunities

Zhu

O’Nolan

Lively

2019

Chemistry A European J

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“…1 The predictable interaction with specific guests motivates 2 incorporation of hosts into polymers for extraction 3 and sensing 4,5 as well as responsive behaviors 6 stemming from their reversible self-assembly. Cation-binding hosts have been used to investigate these types of properties, e.g., crowns, 7 aza-crowns, 8 calixarenes, 9 cucurbiturils: 10 the use of anion receptors is rare, vide infra. 11,12,14 Moreover, a quantitative evaluation of the impact of the polymeric scaffold on anion binding has yet to be investigated.…”

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confidence: 99%

Quantifying chloride binding and salt extraction with poly(methyl methacrylate) copolymers bearing aryl-triazoles as anion receptor side chains

McDonald¹,

Qiao²,

Twum³

et al. 2014

Chem. Commun.

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Copolymers of methyl methacrylate and aryl-triazole based anion receptors were quantitatively analyzed. Transfer of structural features (1 : 1 and 2 : 1 complexes) and Cl(-) affinities from the parent receptors was demonstrated. Cl(-)-induced cross-linking changed the polymer's hydrodynamic radius. Extraction of tetrapropylammonium Cl(-) from water to dichloromethane was enhanced over PMMA.

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“…[1][2][3] The interest stems not only from the fact that these studies provide unlimited exploration of structural assembly 4,5 but also from the chemical and biological potential of these compounds as ion exchangers 6 and possible agents for transporting ionic species in living tissues. 10 One way to overcome this problem is to attach the macrocyclic ligands covalently to a solid support. 8,9 However, one of the major problems encountered in using macrocyclic ligands in separation processes is the loss of very expensive macrocycles in the solution due to their solubility.…”

Section: Received October 3 1996mentioning

confidence: 99%

Crown Ether Pillared and Functionalized Layered Zirconium Phosphonates: A New Strategy to Synthesize Novel Ion Selective Materials

1997

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Crown ethers have been intensively studied during the last 25 years. 1-3 The interest stems not only from the fact that these studies provide unlimited exploration of structural assembly 4,5 but also from the chemical and biological potential of these compounds as ion exchangers 6 and possible agents for transporting ionic species in living tissues. 7 These macrocyclic ligands are noted for their remarkable selectivity toward metal ions making them excellent choices for the separation of metal ions. 8,9 However, one of the major problems encountered in using macrocyclic ligands in separation processes is the loss of very expensive macrocycles in the solution due to their solubility. 10 One way to overcome this problem is to attach the macrocyclic ligands covalently to a solid support. Early efforts to accomplish this chemical bonding involved connecting the carbon framework of the macrocycles to the siloxy component of silica gel. 11,12 However, this method proved to be fraught with preparative difficulties that involves several reaction steps.Metal phosphonates represent a relatively new class of compounds. 13,14 Many of them are layered compounds in which inorganic groups build up the layer backbone while the organic portion protrudes into the interlamellar space. One of the noted characteristics of these compounds is their predictable structure skeletons. 15,16 Other important features are the simple reaction steps required to make them and the ability to affix the various organic groups on a solid support. 17 In this paper, we report our efforts to incorporate crown ethers onto zirconium phosphonate layers. The crown ether precusors used here are 1-aza-15-crown-5 and 1,4,10,13-tetraoxa-7,16diazacyclooctadecane. They were converted to phosphonic acids by a Mannich type reaction, 18 from which a series of bridged and unbridged zirconium phosphonates were synthesized. Kijima 19 recently reported incorporating the macrocyclic species into the R-and γ-zirconium phosphate by intercalation.Brunet et al. 20 and Alberti 14,21 also were able to bind the crown ether covalently to γ-zirconium phosphate by an ester exchange reaction. Our synthesis, however, is a new general approach to react macrocycle phosphonic acids with zirconium, and the products obtained are the first examples of bridged and nonbridged crown ether derivatized zirconium phosphonates prepared by direct reaction rather than ester interchange and therefore may be more general.The preparation is outlined in Scheme 1. Compound 3 was made from phosphonic acid 2 when the ratio of 2 to phosphoric acid was equal to 2. The X-ray diffraction pattern, shown in Figure 1, suggested that it is a layered compound with a d-spacing of 20.0 Å. When the reaction was performed with additional phosphoric acid, a new layered phase, 4, with d-spacing 13.0 Å, was obtained. The structural difference between these two phases was easily identified from their 31 P solid state NMR spectra. The 31 P NMR spectrum of 3 has two main peaks similar to those obtained for zirconium N-(...

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Macrocycle-metal cation interactions involving polyaza macrocycles bonded to silica gel via a nitrogen donor atom

Abstract: Abstract

Cited by 35 publications

References 1 publication

Molecularly Mixed Composite Membranes: Challenges and Opportunities

Molecularly Mixed Composite Membranes: Challenges and Opportunities

Quantifying chloride binding and salt extraction with poly(methyl methacrylate) copolymers bearing aryl-triazoles as anion receptor side chains

Crown Ether Pillared and Functionalized Layered Zirconium Phosphonates: A New Strategy to Synthesize Novel Ion Selective Materials

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