Host–guest interactions template: the synthesis of a [3]catenane

Hubbard, Amy L.; Davidson, Gregory J. E.; Patel, Roopa H.; Wisner, James A.; Loeb, Stephen J.

doi:10.1039/b312449e

Cited by 71 publications

(30 citation statements)

References 16 publications

(14 reference statements)

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“…construct a variety of interlocked molecules and materials by means of this self-assembly strategy. [13][14][15][16][17] Almost any metal complex with a single, open coordination site is bulky enough to be used as an effective stopper and single metalion nodes result in 1D, 2D, or 3D metal-ligand frameworks with rotaxane bridging ligands (MORFs). [18] One of the shortcomings of any self-assembly strategy for metal-ion incorporation is that formation of the metalligand bonds must be compatible with maintaining the weaker non-covalent interactions between axle and wheel (ion-dipole, hydrogen bonding, and p-stacking interactions).…”

Section: Introductionmentioning

confidence: 99%

Wire‐Type Ruthenium(II) Complexes with Terpyridine‐Containing [2]Rotaxanes as Ligands: Synthesis, Characterization, and Photophysical Properties

Davidson

Loeb

Passaniti

et al. 2006

Chemistry A European J

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[2]Rotaxanes based on the 1,2-bis(pyridinium)ethane subset[24]crown-8 ether motif were prepared that contain a terminal terpyridine group for coordination to a transition-metal ion. These rotaxane ligands were utilized in the preparation of a series of heteroleptic [Ru(terpy)(terpy-rotaxane)]2+ complexes. The compounds were characterized by 1D and 2D 1H NMR spectroscopy, X-ray crystallography, and high-resolution electrospray ionization mass spectrometry. The effect of using a rotaxane as a ligand was probed by UV/Vis/NIR absorption and emission spectroscopy of the Ru(II) complexes. In contrast with the parent [Ru(terpy)(2)]2+ complex, at room temperature the examined complexes exhibit a luminescence band in the near infrared region and a relatively long lived triplet metal-to-ligand charge-transfer (3MLCT) excited state, owing to the presence of strong-electron-acceptor pyridinium substituents on one of the two terpy ligands. Visible-light excitation of the Ru-based chromophore in acetonitrile at room temperature causes an electron transfer to the covalently linked 4,4'-bipyridinium unit and the quenching of the MLCT luminescence. The 3MLCT excited state, however, is not quenched at all in rigid matrix at 77 K. The rotaxane structure was found to affect the absorption and luminescence properties of the complexes. In particular, when a crown ether surrounds the cationic axle, the photoinduced electron-transfer process is slowed down by a factor from 2 to 3. Such features, together with the synthetic and structural advantages offered by [Ru(terpy)2]2+-type complexes compared to, for example, [Ru(bpy)3]2+-type compounds, render these rotaxane-metal complexes promising candidates for the construction of photochemical molecular devices with a wire-type structure.

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Section: Introductionmentioning

confidence: 99%

Wire‐Type Ruthenium(II) Complexes with Terpyridine‐Containing [2]Rotaxanes as Ligands: Synthesis, Characterization, and Photophysical Properties

Davidson

Loeb

Passaniti

et al. 2006

Chemistry A European J

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“…[11] In particular, we reportedt hat 1,2-bis(pyridinium)ethane dications (1 2 + )c ould be used as axles to form [2]pseudorotaxanesw ith 24-membered crown ethers such as commercially available dibenzo . [11c] This has also been shown to be av ersatile motif fort he formation of [2]rotaxanes, [12] [3]rotaxanes, [13] [3]catenanes, [14] molecular shuttles, [15] branched [n]rotaxanes( n = 2-4) [16] and metal-organic rotaxane frameworks (MORFs). [9,17] Imidazolium and benzimidazolium cations have also been found to complex macrocycle hosts such as crown ethers, cryptands, and pillararenes.…”

Section: Introductionmentioning

confidence: 99%

Acid‐Base Switchable [2]‐ and [3]Rotaxane Molecular Shuttles with Benzimidazolium and Bis(pyridinium) Recognition Sites

Zhu

Vukotic

2016

Chemistry An Asian Journal

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For the purpose of developing higher level mechanically interlocked molecules (MIMs), such as molecular switches and machines, a new rotaxane system was designed in which both the 1,2-bis(pyridinium)ethane and benzimidazolium recognition templating motifs were combined. These two very different recognition sites were successfully incorporated into [2]rotaxane and [3]rotaxane molecular shuttles which were fully characterized by H NMR, 2D EXSY, single-crystal X-ray diffraction and VT NMR analysis. By utilizing benzimidazolium as both a recognition site and stoppering group it was possible to create not only an acid/base switchable [2]rotaxane molecular shuttle (energy barrier 20.9 kcal⋅mol ) but also a [3]rotaxane molecular shuttle that displays unique dynamic behavior involving the simultaneous motion of two macrocyclic wheels on a single dumbbell. This study provides new insights into the design of switchable molecular shuttles. Due to the unique properties of benzimidazoles, such as fluorescence and metal coordination, this new type of molecular shuttle may find further applications in developing functional molecular machines and materials.

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“…Alternatively, Loeb [133] has demonstrated (Scheme 8b) that, when various crown ethers, such as 24C8, B24C8, N24C8, BN24C8, DN24C8, and DB24C8, are treated separately with the pyridinium salt 52·2Br and the dibromide 53, then a large number of [3]catenanes 54·8CF 3 SO 3 can be produced. According to the nature of the crown ether, the percentage yields vary from 17% to 66%, with DB24C8 giving the best result.…”

Section: Dipyridiniumethane Templatesmentioning

confidence: 99%

“…In 1998, Loeb and Wisner [19,130] reported that 1,2-bis(pyridinium)ethane and DB24C8 self-assemble to form [2] [131][132] and catenane [133] derivatives. For example, the [3]rotaxanes 50·5BF 4 and 51·6CF 3 SO 3 (Scheme 8a) were made by the monoalkylation of the pyridinium salt 47·4BF 4 or dialkylation of the pyridinium salt 48·4CF 3 SO 3 [131] with 4-tert-butylbenzyl bromide 49, respectively, in the presence of an excess of DB24C8, to afford the [3]rotaxanes, both in about 18% yield.…”

Section: Dipyridiniumethane Templatesmentioning

confidence: 99%

Templated Synthesis of Interlocked Molecules

Aricò

Badjić

Cantrill

et al. 2005

Topics in Current Chemistry

193

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Host–guest interactions template: the synthesis of a [3]catenane

Abstract: Formation of a [3]catenane containing dibenzo-24-crown ether wheels and a large dipyridiniumethane ring is templated by formation of a host-guest adduct between the [3]catenane and the external crown ether.

Cited by 71 publications

References 16 publications

Wire‐Type Ruthenium(II) Complexes with Terpyridine‐Containing [2]Rotaxanes as Ligands: Synthesis, Characterization, and Photophysical Properties

Wire‐Type Ruthenium(II) Complexes with Terpyridine‐Containing [2]Rotaxanes as Ligands: Synthesis, Characterization, and Photophysical Properties

Acid‐Base Switchable [2]‐ and [3]Rotaxane Molecular Shuttles with Benzimidazolium and Bis(pyridinium) Recognition Sites

Templated Synthesis of Interlocked Molecules

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