Template Synthesis of [2]Rotaxanes with Large Ring Components and Tris(biphenyl)methyl Group as the Blocking Group. The Relationship between the Ring Size and the Stability of the Rotaxanes

Saito, Shinichi; Nakazono, Kazuko; Takahashi, Eiko

doi:10.1021/jo060829h

Cited by 35 publications

(33 citation statements)

References 21 publications

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“…The half-lives for the [3]rotaxane (t 1/2 = ln 2/k; k: rate constant for the dissociation reaction of Fig. 7) is around 200 h at 298 K whereas it is approximately 50 h at 333 K. Although direct comparison to other systems [35] is impossible, it must be noted that the enthalpic contribution ( H ‡ ) to the unthreading barrier is rather low whereas the entropic component (k ∞ and S ‡ ) is remarkably high: H ‡ = 33 ± 3 kJ mol −1 and S ‡ = −182 ± 55 J K −1 mol −1 , from which G ‡ (298 K) = 87 ± 9 kJ mol −1 was deduced. The high activation entropy indicates that the unthreading reaction has a highly ordered transition state, i.e., it is strongly dependent on the relative orientation of the ring and the two strings.…”

Section: Demetalation Of the Cobalt(ii)-complexed [3]rotaxane And Stumentioning

confidence: 96%

The magic effect of endocyclic but non-sterically hindering biisoquinoline chelates: From fast-moving molecular shuttles to [3]rotaxanes

Durola

Sauvage

Wenger

2010

Coordination Chemistry Reviews

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Section: Demetalation Of the Cobalt(ii)-complexed [3]rotaxane And Stumentioning

confidence: 96%

The magic effect of endocyclic but non-sterically hindering biisoquinoline chelates: From fast-moving molecular shuttles to [3]rotaxanes

Durola

Sauvage

Wenger

2010

Coordination Chemistry Reviews

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“…This metal has been extensively used as a template in our group [1b, 18] or in other research teams. [19][20][21] Other transition-metal centers have also been used successfully in the templated synthesis of various catenanes and rotaxanes. [22][23][24][25][26] Organic templates, assembled via formation of aromatic acceptor-donor complexes and/or hydrogen bonds, have also been very successful.…”

Section: Introductionmentioning

confidence: 99%

A Fast‐Moving Copper‐Based Molecular Shuttle: Synthesis and Dynamic Properties

Durola

Lux²,

Sauvage³

2009

Chemistry A European J

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Fast-track changes: The synthesis of a new copper-based molecular shuttle is described, with a coordinating macrocycle based on a nonhindering but endocyclic ligand (see scheme), which makes the ligand exchange easier, and thus the motions of the ring along the thread faster.The present report deals with the synthesis of a two-station [2]rotaxane consisting of a dpbiiq-incorporating macrocycle (dpbiiq: 8,8'-diphenyl-3,3'-biisoquinoline) threaded by a coordinating fragment whose complexing units are a dpp and a terpy ligand (dpp: 2,9-diphenyl-1,10-phenanthroline; terpy: 2,2',6',2"-terpyridine). The [2]rotaxane was prepared in 11 steps from commercially available or easy-to-make molecules, without taking into account the preparation of the dpbiiq-containing 39-membered ring, which was available in our group. The ring-incorporated bidentate chelate is at the same time endocyclic and sterically nonhindering, which is a specific property of the dpbiiq-coordinating unit. This unique feature has a profound influence on the rate of the ring-and-copper translation motion between the two stations of the axle. Based on an analogous multistep strategy, a related molecular shuttle has also been prepared that contains exactly the same axle and stoppers as the first compound but whose threaded ring incorporates the sterically hindering dpp chelate. The translation motions of this other system are several orders of magnitude slower than the corresponding movements of the dpbiiq-based compound. The motion corresponding to the rearrangement of the unstable five-coordinate copper(I) form of the compounds is relatively fast for both shuttles; the half lifetime of the five-coordinate Cu(I) species being below 20 ms for the dpbiiq-containing system and below 1 s for the dpp-based molecule. The reverse motion corresponding to the rearrangement of the four-coordinate copper(II) complexes is much slower, especially for the dpp-based system. It is of the order of several hours for the dpp-based shuttle and only one second or less for the dpbiiq system, under exactly the same conditions. The remarkable difference between the motion rates for the two two-station shuttles demonstrates that the use of a very open chelate such as dpbiiq is extremely beneficial in the context of fast-moving molecular machines.

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“…[143] Saito erforschte die Grenzen zwischen Rotaxanen und Pseudorotaxanen, indem er mit einem Cu I (dpp) 2 -Templat und großen (33-bis 45-gliedrigen) Makrocyclen Rotaxane bildete. [144] Sauvage und Diederich befestigten durch eine oxidative Acetylenkupplung (unter der Verwendung des Vorläufers in Schema 11 b) kovalent Fullerene und stellten so [2]Rotaxane zur Untersuchung elektrochemischer und photoinduzierter Prozesse her. [145] Eine interessante Eigenschaft verschlungener Moleküle ist deren Potenzial zur Bildung topologisch chiraler Strukturen.…”

Section: Angewandte Chemieunclassified

Strategien und Taktiken für die metallgesteuerte Synthese von Rotaxanen, Knoten, Catenanen und Verschlingungen höherer Ordnung

et al. 2011

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Mehr als ein Vierteljahrhundert nach der ersten Metalltemplatsynthese eines [2]Catenans in Straßburg existiert nun eine Fülle an Strategien zum Aufbau mechanisch verbundener und verflochtener Strukturen auf molekularer Ebene. Catenane, Rotaxane, Knoten und Borromäische Ringe sind alle erfolgreich über Methoden zugänglich, in denen Metallionen eine Schlüsselrolle spielen. Ursprünglich wurden Metallionen ausschließlich aufgrund ihrer Koordinationschemie verwendet, indem sie entweder die einzelnen Bausteine auf eine Weise anordneten, die durch anschließende Reaktionen die Erzeugung der verschlungenen Produkte ermöglichte, oder indem sie selbst als wesentlicher Bestandteil der Ringe oder als “Stopper” dienten. Vor kurzem wurde die Rolle des Metalls auch auf die Katalyse ausgedehnt: Die Metallionen ordnen die Bausteine nicht nur zu einer verflochtenen oder eingefädelten Struktur an, sondern fördern auch aktiv die Strukturbildung durch kovalenten Einfangen. Dieser Aufsatz fasst die Strategien zur Bildung mechanisch verbundener Molekülstrukturen mit Metallionen zusammen und diskutiert die Taktiken, die zum Aufbau von Überkreuzungen, zur Maximierung der Ausbeuten verschlungener und nichtverschlungener Produkte und zur Bildung eingefädelter oder verflochtener Intermediate durch kovalenten Einfang zur Verfügung stehen.

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Template Synthesis of [2]Rotaxanes with Large Ring Components and Tris(biphenyl)methyl Group as the Blocking Group. The Relationship between the Ring Size and the Stability of the Rotaxanes

Cited by 35 publications

References 21 publications

The magic effect of endocyclic but non-sterically hindering biisoquinoline chelates: From fast-moving molecular shuttles to [3]rotaxanes

The magic effect of endocyclic but non-sterically hindering biisoquinoline chelates: From fast-moving molecular shuttles to [3]rotaxanes

A Fast‐Moving Copper‐Based Molecular Shuttle: Synthesis and Dynamic Properties

Strategien und Taktiken für die metallgesteuerte Synthese von Rotaxanen, Knoten, Catenanen und Verschlingungen höherer Ordnung

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