A Self-Assembled Metallomacrocyclic Ionophore with High Affinity and Selectivity for Li<sup>+</sup> and Na<sup>+</sup>

Piotrowski, Holger; Polborn, Kurt; Hilt, Gerhard; Severin, Kay

doi:10.1021/ja005804t

Cited by 170 publications

(93 citation statements)

References 14 publications

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“…The alkali metal ion is expected to be captured on a triangle of the central oxygen atoms. [3][4][5] The cavity radius (rc) of the oxygen triangle is 0.045 nm for 3, which is nearly equal to those reported for 1 and 2 (rc = 0.042 and 0.047 nm, respectively). 7 However, the structure of 3 reveals that the oxygen atoms are more effectively shielded by the p-ligands than in the cases with 1 and 2.…”

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confidence: 51%

“…Recently, Severin and coworkers synthesized a new class of ionophores, macrocyclic trinuclear organometallic complexes bridged by 2,3-dioxopyridine. [3][4][5][6] These complexes are electrically neutral, and some of them function as ligands or extractants for Li + and Na + . One of the features of the trinuclear complexes is that they are self-assembly formed and can be more easily synthesized than the conventional synthetic ionophores.…”

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confidence: 99%

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Selective Extraction of Lithium with a Macrocyclic Trinuclear Complex of (1,3,5-Trimethylbenzene)ruthenium(II) Bridged by 2,3-Dioxopyridine

et al. 2008

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The quantitative and selective extraction of Li + from aqueous solutions is a difficult subject because of a strong hydration of Li + . Up to now, several kinds of Li + -selective ionophores have been synthesized, such as spherands 1 and 14-crown-4 derivatives, 2 most of which have been studied as sensing materials for Li + -selective electrodes. Recently, Severin and coworkers synthesized a new class of ionophores, macrocyclic trinuclear organometallic complexes bridged by 2,3-dioxopyridine.3-6 These complexes are electrically neutral, and some of them function as ligands or extractants for Li + and Na + . One of the features of the trinuclear complexes is that they are self-assembly formed and can be more easily synthesized than the conventional synthetic ionophores. Additionally, it has been shown that the extraction selectivity of the trinuclear complexes of (p-cymene)ruthenium(II) (1) and (pentamethylcyclopentadienyl)rhodium(III) (2) for Li + over Na + is comparable to, or higher than, that of a commercially available 14-crown-4 derivative. 7 However, their extraction ability and selectivity are not sufficient for the quantitative extraction and separation of Li + from Na + by a single extraction process. In this communication, we describe a newly synthesized trinuclear complex of (1,3,5-trimethylbenzene)ruthenium(II) bridged by 2,3-dioxopyridine (3), which has a much higher selectivity for Li + in solvent extraction. The structural formulas of 1, 2, and 3 are shown in Fig. 1.The trinuclear complex 3 was obtained by a room-temperature reaction of [(1,3,5-trimethylbenzene)RuCl2]2 with 2,3-dihydroxypyridine. 8 Here, [(1,3,5-trimethylbenzene)RuCl2]2 was prepared by refluxing a suspension of [(p-cymene)RuCl2]2 in degassed 1,3,5-trimethylbenzene. 9 The solid complex was relatively stable, even in air, and could be kept for several months under a nitrogen atmosphere.The stability of 3 in a dichloromethane/water system was examined without degassing and nitrogen purging treatments. Complex 3 had an absorption maximum at 333 nm (e = 2.43 ¥ 10 4 dm 3 mol -1 cm -1 ) in dichloromethane at 25˚C. After shaking the dichloromethane solution of 3 (3 ¥ 10 -3 mol dm -3 ) with deionized water, a small amount of precipitate formed at the liquid-liquid interface; however, the light absorption of 3 in the organic phase was practically the same as that before shaking, and remained unchanged within a shaking period of 40 h. It was also found that the partition of 3 from the organic phase to the aqueous one was negligibly small.The extraction of lithium picrate (1 ¥ 10 -3 mol dm -3 ) or sodium one (1 ¥ 10 -2 mol dm -3 ) in an aqueous solution with a dichloromethane solution of 3 (6 ¥ 10 -4 -6 ¥ 10 -3 mol dm -3 ) was conducted at 25˚C in a similar manner to that described previously. 7 The distribution ratio (D) was calculated from the alkali metal concentrations in both the organic and aqueous phases, determined by atomic absorption spectrophotometry. The recovery of the alkali metal from the two phases was always quantitative. ...

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Selective Extraction of Lithium with a Macrocyclic Trinuclear Complex of (1,3,5-Trimethylbenzene)ruthenium(II) Bridged by 2,3-Dioxopyridine

et al. 2008

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“…In elaboration of a synthetic scheme which we have reported recently (14,15), the trinuclear metallamacrocycle 1 was obtained by reaction of commercially available 3-hydroxy-2-pyridone with [(C 6 H 5 CO 2 Et)RuCl 2 ] 2 in the presence of base (Scheme 1). The chloro-bridged ruthenium complex used in this reaction is a common starting material in organometallic chemistry and can easily be obtained from RuCl 3 ⅐(H 2 O) n and ethyl-1,4-cyclohexadiene-3-carboxylate (16).…”

Section: Resultsmentioning

confidence: 99%

A self-assembled, redox-responsive receptor for the selective extraction of LiCl from water

Piotrowski

Severin

2002

Proc. Natl. Acad. Sci. U.S.A.

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There is considerable interest in synthetic ionophores with high affinity and selectivity for Li ؉ . But so far, compounds that selectively bind Li ؉ in the presence of other alkali and alkaline earth metal ions are rare and current approaches toward this goal are often accompanied with substantial synthetic efforts. Here we describe a trinuclear ruthenium metallamacrocyclic complex (1) that was obtained by self-assembly of ruthenium halfsandwich complexes and 3-hydroxy-2-pyridone ligands. This complex was shown to be an extremely potent receptor for LiCl with an affinity high enough to extract LiCl from water. The selectivity of this receptor is exceptional: even in the presence of a large excess of Na ؉ , K ؉ , Cs ؉ , Ca 2؉ , and Mg 2؉ , Li ؉ was extracted exclusively. The Li ؉ ͞Na ؉ selectivity ratio was determined to be higher than 1,000:1. Compared with other synthetic ionophores, the receptor 1 offers two additional advantages: (i) the synthesis can be accomplished in one step by using simple starting materials; and (ii) the presence of lithium ions can be detected electrochemically. Complex 1 is therefore a very attractive candidate for the construction of a Li ؉ -specific chemosensor.L ithium salts have found various applications in technology and medicine. Methods to selectively sequester and detect Li ϩ are therefore of importance. Li 2 CO 3 , for example, is one of the most important drugs for the treatment of manic depression (1, 2). Because of its narrow therapeutic range, the Li ϩ concentration in the blood of the patients needs to be controlled during the treatment. Thus, a small amount Li ϩ has to be detected in the presence of other metal ions such as Na ϩ , K ϩ , Ca 2ϩ , and Mg 2ϩ (3).To selectively sequester Li ϩ , ionophores have been considered early on. But the design and the synthesis of molecules that display a high affinity and selectivity for Li ϩ is a challenging task (4-9). Although considerable progress has been made in this field, the synthesis of such ionophores often requires substantial synthetic efforts. This difficulty is nicely illustrated by probably the best Li ϩ receptor known so far, a spherand developed by Cram and his colleagues (10). Because of the perfect preorganization of six oxygen donor atoms, a very high affinity combined with an excellent selectivity for Li ϩ is observed. The synthesis, however, requires several steps and gives less than 7% overall yield.Here we describe a redox-responsive metallamacrocycle (1; see Scheme 1) that was obtained by self-assembly (for selfassembled metallacrowns see ref. 11). With this receptor we were able to selectively extract LiCl from an aqueous solution containing an excess of NaCl, KCl, CsCl, CaCl 2 , and MgCl 2 . The presence of LiCl can subsequently be detected by electrochemical means. Materials and MethodsGeneral. The synthesis of all complexes was performed under an atmosphere of dry dinitrogen, by using standard Schlenk techniques. The 1 H, 13 C, and 7 Li spectra were recorded on a JEOL EX 400 or a GSX 270 spectrometer u...

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“…These molecules have already been used in applications as diverse as catalysis, [1] sensors, [2] or as chiral building blocks for two-and three-dimensional solids. [3] Metallamacrocyles include complexes such as metallacrowns, [3, 4] molecular squares, [1,2] metallacalixarenes, [5] and metallahelicates.[6] Metallacrowns (MC), the inorganic structural and functional analogs to crown ethers, are usually formed with transition-metal ions incorporated into the metallamacrocyclic ring, thus providing the attractive feature that they concentrate a large number of metal ions per unit volume. This large metal-ion concentration may lead to interesting magnetic behavior.…”

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Synthesis and Magnetic Properties of a Metallacryptate that Behaves as a Single‐Molecule Magnet

et al. 2003

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Metallamacrocyles have been intensively studied over the past decade. These molecules have already been used in applications as diverse as catalysis, [1] sensors, [2] or as chiral building blocks for two-and three-dimensional solids. [3] Metallamacrocyles include complexes such as metallacrowns, [3, 4] molecular squares, [1,2] metallacalixarenes, [5] and metallahelicates.[6] Metallacrowns (MC), the inorganic structural and functional analogs to crown ethers, are usually formed with transition-metal ions incorporated into the metallamacrocyclic ring, thus providing the attractive feature that they concentrate a large number of metal ions per unit volume. This large metal-ion concentration may lead to interesting magnetic behavior. [4,7] Since the recognition of single-molecule magnets (SMMs) in 1993, the field has gained considerable attention as a study of both classical and quantum effects. [8,9] SMMs of cobalt, [10] vanadium, [11] nickel, [12] iron, [13] and a mixed-metal system [14] have been studied. However, the best known and most intensely studied SMMs are the manganese carboxlyate clusters, which range in size from Mn 4 to Mn 30 .[15] Herein we report the synthesis (Scheme 1) and characterization of the second [16] known Mn 26 complex [Mn

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A Self-Assembled Metallomacrocyclic Ionophore with High Affinity and Selectivity for Li⁺ and Na⁺

Cited by 170 publications

References 14 publications

Selective Extraction of Lithium with a Macrocyclic Trinuclear Complex of (1,3,5-Trimethylbenzene)ruthenium(II) Bridged by 2,3-Dioxopyridine

Selective Extraction of Lithium with a Macrocyclic Trinuclear Complex of (1,3,5-Trimethylbenzene)ruthenium(II) Bridged by 2,3-Dioxopyridine

A self-assembled, redox-responsive receptor for the selective extraction of LiCl from water

Synthesis and Magnetic Properties of a Metallacryptate that Behaves as a Single‐Molecule Magnet

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A Self-Assembled Metallomacrocyclic Ionophore with High Affinity and Selectivity for Li+ and Na+

Cited by 170 publications

References 14 publications

Selective Extraction of Lithium with a Macrocyclic Trinuclear Complex of (1,3,5-Trimethylbenzene)ruthenium(II) Bridged by 2,3-Dioxopyridine

Selective Extraction of Lithium with a Macrocyclic Trinuclear Complex of (1,3,5-Trimethylbenzene)ruthenium(II) Bridged by 2,3-Dioxopyridine

A self-assembled, redox-responsive receptor for the selective extraction of LiCl from water

Synthesis and Magnetic Properties of a Metallacryptate that Behaves as a Single‐Molecule Magnet

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A Self-Assembled Metallomacrocyclic Ionophore with High Affinity and Selectivity for Li⁺ and Na⁺