Lithium‐Templated Synthesis of a Donor–Acceptor Pseudorotaxane and Catenane

Kaiser, Guido; Jarrosson, Thibaut; Otto, Sijbren; Ng, Yiu‐Fai; Bond, Andrew D.; Sanders, Jeremy K. M.

doi:10.1002/ange.200353075

Cited by 58 publications

(12 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[15] Upon addition of Li + , the oligo(ethylene glycol) moiety of the macrocycle and the amide oxygen atom encircle the Li + ion and coordinate to it, which leads to clear downfield shifts of H k and the protons of the oligo(ethylene glycol) moiety. In addition, the signals for pyridine protons H o and H p shifted downfield by 0.85 and 0.42 ppm, respectively.…”

Section: Wwwchemeurjorgmentioning

confidence: 99%

“…As a result, the hydrogen bonds between dialkylammonium and oligo(ethylene glycol) groups are switched off, and the macrocycle moves to the amide recognition site due to the hydrogen bond between them. Upon addition of 1.2 equivalents of Li + ions, the conformation of the [2]rotaxane is altered by a combination of Li-oligo(ethylene glycol) interaction [15] and weak hydrogen bonds between amide and pyridine groups. When 1.1 equivalents of Zn 2 + ions are added, the pyridine/aniline moiety in the macrocycle and the amine in the thread complex with Zn 2 + , and the macrocycle returns to the amine site.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Molecular Shuttle for Driving a Multilevel Fluorescence Switch

Zhou

et al. 2007

Chemistry A European J

128

View full text Add to dashboard Cite

A [2]rotaxane-based molecular shuttle comprised a macrocycle mechanically interlocked to a chemical "dumbbell" has been prepared in high yields by a thermodynamically controlled, template-induced clipping procedure. This molecular shuttle has two different recognition sites, namely, -NH2 +- and amide, separated by a phenyl unit. The macrocycle exhibits high selectivity for the -NH2+- recognition sites in the protonated form through noncovalent interactions, which include 1) N+-H...O hydrogen bonds; 2) C-H...O interactions between the CH2NH2+CH2 protons on the thread and the oligo(ethylene glycol) unit in the macrocycle; 3) pi...pi stacking interaction between macrocycle and aromatic unit. Upon deprotonation of the [2]rotaxane the macrocycle glides to the amide recognition site due to the hydrogen bonds between the -CONH- group and the oligo(ethylene glycol) unit in the macrocycle. The deprotonation process requires about 10 equivalents of base (iPr2NEt) in polar acetone, while the amount of base is only 1.2 equivalents in apolar tetrachloroethane. Upon addition of Li+, the conformation of the [2]rotaxane was altered as a result of the collective interactions of 1) hydrogen bonds between pyridine nitrogen and amide hydrogen atoms; 2) coordination between the oligo(ethylene glycol) unit, amide oxygen atom and Li+ cation. Then, when Zn2+ ions are added, the macrocycle returns to the deprotonated -NH- recognition site owing to coordination of the macrocycle and -NH- from the axle with the Zn2+ ion. All the above-mentioned movement processes are reversible through the alternate addition of TFA/iPr2NEt, Li/[12]-crown-4 and Zn2+/ethylenediaminetetraacetate (EDTA), by virtue of hydrogen bonding and metal-ion complexation. Significantly, the three independent movement processes are all accompanied by fluorescent responses: 1) complete repression in the protonated form; 2) low-level expression in the deprotonated form; 3) medium-level expression following addition of Li+; 4) high-level expression on complexation with Zn2+.

show abstract

Section: Wwwchemeurjorgmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Molecular Shuttle for Driving a Multilevel Fluorescence Switch

Zhou

et al. 2007

Chemistry A European J

128

View full text Add to dashboard Cite

show abstract

“…In one example, Li + ions have been used to assist the formation of a unique donor-acceptor pseudorotaxane, [8] but it appears that Na + ions play a similar role in that system. [9] We became interested in forming pseudorotaxanes in solution with high efficiency and selectivity toward a single species of alkalimetal ion-especially if we could differentiate between the physiologically important, [10] but chemically similar, Na + and K + ions.…”

mentioning

confidence: 99%

Highly Selective Na⁺‐Templated Formation of [2]Pseudorotaxanes Exhibiting Significant Optical Outputs

et al. 2007

View full text Add to dashboard Cite

The diverse range of binding geometries exhibited by metal ions and their relatively stable interactions with ligands can be exploited for the efficient template-directed synthesis of macrocycles,[1] supramolecular architectures, [2] and interlocked molecules.[3] Although the formation of rotaxanes or pseudorotaxanes has been demonstrated using transitionmetal ions coordinated to four (tetrahedral and square planar), [4] five (trigonal bipyramidal and square pyramidal), [5] and six (octahedral) [6] donor atoms, alkali-metal ions, which are useful templates for the synthesis of crown ethers, [7] are rarely used to direct the construction of such complexes. In one example, Li + ions have been used to assist the formation of a unique donor-acceptor pseudorotaxane, [8] but it appears that Na + ions play a similar role in that system. [9] We became interested in forming pseudorotaxanes in solution with high efficiency and selectivity toward a single species of alkalimetal ion-especially if we could differentiate between the physiologically important, [10] but chemically similar, Na + and K + ions.[11] Herein, we report a new molecular recognition system based on the molecular cage 1 (Scheme 1) and two different threadlike molecules (anthraquinone and squaraine), each of which forms a pseudorotaxane complex with 1 in the presence of templating Na + ions and exhibits high selectively over the other alkali-metal ions tested. This ionspecific templating effect was easy to monitor because the complexation and decomplexation of the pseudorotaxane complexes in solution occurred with color changes that were detectable to the naked eye. It appears from the solid-state structures that the dramatic Na Previously, we demonstrated that molecular cage 2 and anthraquinone (3, Scheme 2) can form pseudorotaxane-like complexes in solution when K + ions are present. [12] We suspected that greater ion-selective templating behavior would arise if we replaced the two openings resembling dibenzo [24]crown-8 (DB24C8) in 2 with two relatively smaller and more rigid units resembling dibenzo [18]crown-6

show abstract

“…In Figure 11.4 is a crown ether derived naphthalene macrocycle whose weak affi nity for a pyromellitic diimide is increased by an order of magnitude by the presence of lithium salts. 15 The crown ether oxygens coordinate to the lithium cations which in turn promotes simultaneous dye inclusion. The result is a stunning colour change from a pale yellow to bright red due to formation of a charge transfer complex.…”

Section: Reversible Dye Encapsulation Inside Organic Container Moleculesmentioning

confidence: 99%

Dye Encapsulation

Gassensmith

Arunkumar

Smith

2010

Molecular Encapsulation

View full text Add to dashboard Cite

Lithium‐Templated Synthesis of a Donor–Acceptor Pseudorotaxane and Catenane

Abstract: Durch simultane Koordination eines aromatischen Elektronendonors und eines aromatischen Elektronenacceptors an Lithium entsteht ein stabiler farbiger Pseudorotaxankomplex (siehe Bild), der als Vorstufe für ein [2]Catenan dient.

Cited by 58 publications

References 36 publications

A Molecular Shuttle for Driving a Multilevel Fluorescence Switch

A Molecular Shuttle for Driving a Multilevel Fluorescence Switch

Highly Selective Na⁺‐Templated Formation of [2]Pseudorotaxanes Exhibiting Significant Optical Outputs

Dye Encapsulation

Contact Info

Product

Resources

About

Lithium‐Templated Synthesis of a Donor–Acceptor Pseudorotaxane and Catenane

Abstract: Durch simultane Koordination eines aromatischen Elektronendonors und eines aromatischen Elektronenacceptors an Lithium entsteht ein stabiler farbiger Pseudorotaxankomplex (siehe Bild), der als Vorstufe für ein [2]Catenan dient.

Cited by 58 publications

References 36 publications

A Molecular Shuttle for Driving a Multilevel Fluorescence Switch

A Molecular Shuttle for Driving a Multilevel Fluorescence Switch

Highly Selective Na+‐Templated Formation of [2]Pseudorotaxanes Exhibiting Significant Optical Outputs

Dye Encapsulation

Contact Info

Product

Resources

About

Highly Selective Na⁺‐Templated Formation of [2]Pseudorotaxanes Exhibiting Significant Optical Outputs