Stereoselective Synthesis of a Topologically Chiral Molecule: The Trefoil Knot

Perret-Aebi, Laure-Emmanuelle; Zelewsky, Alex von; Dietrich‐Buchecker, Christiane; Sauvage, Jean‐Pierre

doi:10.1002/anie.200460250

Cited by 100 publications

(41 citation statements)

References 31 publications

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“…The C 2 -symmetry of the ligand is conserved and most of the peaks are shifted to higher fields compared with those for the free ligand. The signal of the pair of protons from the bridge (20) is strongly shifted in the broad-line spectrum at 25°C (kd = 0.9 ppm) and at 50°C (kd = 0.5 ppm) suggesting complete coordination to the metal center of all the bipyridine arms.…”

Section: Complexation Of L1 With Ag(i)mentioning

confidence: 98%

“…In supramolecular chemistry, pinene polypyridine ligands play an important role and have been used to form chiral molecules, like helicates [18], complex squares [19] or molecular knots [20] in their enantiopure form. In the self-assembly of helicates, the so-called Chiragen ligands (they possess two building blocks connected via a bridge between the chiral carbons situated in the alpha position to the pyridine cycle) have made a primordial contribution.…”

Section: Introductionmentioning

confidence: 99%

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Self-assembly of Ag(I) helicates with new enantiopure 5,6-Chiragen type ligands

Mamula

Bark

Quinodoz

et al. 2018

Inorganica Chimica Acta

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Two new chiral bis-bidentate, C2-symmetrical ligands belonging to the Chiragen family have been synthesised and characterised. They are designed for polynuclear self-assemblies since the two (À)-5,6-pinenebipyridines units are connected by bridges whose length and rigidity avoids the coordination of the bipyridine moieties to the same metal centre. The ligand L1 with a 1,4-dimethylene naphthalene bridge leads, by complexation with Ag(I) cations, to a polymeric, single stranded helix. The helical pitch contains five metal centers, two consecutive metal centers being connected by a bis-bidentate, helically wrapped ligand, one up and the other down resulting in a coordination number four. The chirality (K) around each metal centre is controlled by the six asymmetric carbons of the ligands and the homochirality of the metal centers gives rise to a P orientation at the helix level. The 1 H-NMR measurements of these species in solution indicate a temperature dependent behaviour pointing out possible equilibria between various [Ag n L n ] n+ fragments as confirmed by MS-spectroscopy. The ligand L2 with a 4,4 0 -dimethylene-1,1 0 -biphenyl bridge reacts with Ag(I) and lead to well resolved and temperature independent 1 H-NMR spectra suggesting the formation of a circular helicate.

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Section: Complexation Of L1 With Ag(i)mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Self-assembly of Ag(I) helicates with new enantiopure 5,6-Chiragen type ligands

Mamula

Bark

Quinodoz

et al. 2018

Inorganica Chimica Acta

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“…[67] Die Verwendung enantiomerenreiner chiraler Liganden ermçglichte die Synthese eines einzelnen Enantiomers des Kleeblattknotens 8 und zeigte das erste Mal den Einfluss von geometrischer Chiralitäta uf topologische Chiralitätine inem molekularen Knoten. [68] [69] schlug…”

Section: Angewandte Chemieunclassified

“…Einige Beispiele fürt opologische Chiralitäti nK leinmolekülknoten wurden eingehender studiert, da es mçglich war, [68,73,74,84,87,99] oder die racemischen Knotengemische in die Enantiomere aufzutrennen. [64,67,83,107,110] Knotens einen signifikanten Effekt auf die Asymmetrie der Chromophor-Umgebung hat.…”

Section: Chiralitätunclassified

Molekulare Knoten

Fielden¹,

Leigh²,

Woltering³

2017

Angewandte Chemie

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Der erste synthetische Kleeblattknoten wurde in den späten 1980er Jahren hergestellt. Kompliziertere Knotentopologien wurden jedoch erst in den letzten Jahren in molekularer Form erhalten. Die Verknotung molekularer Stränge erzeugt sterische Einschränkungen und kann so wichtige physikalische und chemische Eigenschaften verleihen, unter anderem Chiralität, starkes und selektives Binden von Ionen und katalytische Aktivität. Da die Anzahl und Komplexität molekularer Knoten steigt, wird es für Chemiker immer wichtiger, die Knotennomenklatur anderer Disziplinen zu verwenden. Hier geben wir einen Überblick über die Synthesestrategien für molekulare Knoten und beschreiben die Grundlagen der Knoten‐, Zopf‐ und Tangle‐Theorie in einem für Chemiker und molekulare Strukturen angemessenen Umfang.

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“…The The configuration of the two individual Ag-chromophores is D-, the helicity of the dinuclear species is M. The silver structure appears nicely wound and therefore well adapted to the formation of the knot by connecting the appropriate ends of the strands. With the aim of preparing a configurationally predetermined molecular knot, 5 ligand 1 has been alkylated in a stereoselective manner with two polyoxoethylene chains 5, each possessing a terminal olefin.…”

mentioning

confidence: 99%