Molekulare Knoten

Fielden, Stephen D. P.; Leigh, David A.; Woltering, Steffen L.

doi:10.1002/ange.201702531

Cited by 64 publications

(7 citation statements)

References 174 publications

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“…To chemists, the construction of various molecular knots is one of the major interests [3] . To date, only very few relatively simple knot topologies (out of more than six billion prime knots defined mathematically) have been synthesized from small‐molecule building blocks [1a,b] . The first trefoil knot was synthesized by metal‐ion templation in late 1980s by Sauvage et al., [4] while several more complex knots (pentafoil 5 1 , [5] Figure‐of‐eight 4 1 , [6] septafoil 7 1 , [7] nonafoil 9 1 , [8] 8 19 , [9] and a molecular endless 7 4 knot [10] ) have only been obtained very recently.…”

Section: Introductionmentioning

confidence: 99%

A Hydrogen‐Bonded Ravel Assembled by Anion Coordination

Zhao

Wang

et al. 2021

Angew Chem Int Ed

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Anion-coordination-driven assembly (ACDA) is showing increasing power in the construction of anionic supramolecular architectures.H erein, by expanding the anion centers from oxoanion (phosphate or sulfate) to organic triscarboxylates,a nA rchimedean solid (truncated tetrahedron) and ah ighly entangled, double-walled tetrahedron featuring ar avel topology have been assembled with tris-bis(urea) ligands.T he results demonstrate the promising ability of triscarboxylates as new anion coordination centers in constructing novel topologies with increasing complexity and diversity compared to phosphate or sulfate ions on account of the modifiable sizea nd easy functionalization character of these organic anions.

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Section: Introductionmentioning

confidence: 99%

A Hydrogen‐Bonded Ravel Assembled by Anion Coordination

Zhao

Wang

et al. 2021

Angew Chem Int Ed

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“…In nature, some proteins, approximately 1% of those deposited in the Protein Data Bank [1] and DNA [2], spontaneously form flexible structures with a defined molecules have been synthesized with a knot topology, for example, the most recent synthesis for 8 19 knot, which has 8 non-alternating crosses, 192 atoms in a closed loop and is approximately 20 nm in length [5][6][7]. The tightness of these knotted structures is involved in the thermostability of some proteins and studies reveal that it has consequences for their tensile strength [8,9].…”

Section: Introductionmentioning

confidence: 99%

819 molecular knot: a theoretical analysis of the electronic structure using an ONIOM approach

Morgon

Souza

2021

J Mol Model

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The present work analyzes the electronic and molecular properties of the 8 19 ([Fe(II) 4 ]C ) and metal-free knot ligand complexes obtained from X-ray crystal structure of molecular 8 19 knot complex [Fe(II) 4 (PF 6 ) 7 ]C . The studies were theoretically investigated by means of DFT, TD-DFT, and ONIOM approaches. Basis sets functions from all-electron calculations for bromine, iodine, and iron atoms were adapted to be used along with relativistic effective core potential, while H, C, N, O, and C atoms were described by Pople basis sets. The diffusion effect of halogen into the 8 19 cavity, UV-Vis, and Electronic Circular Dichroism spectra were also analyzed. All calculations were performed using solvent effect through the SCRF/SMD model and dispersion effects by Grimme methodology. The value of mean separation distance between C and iron atom (7.218Å) is in good agreement with X-ray experimental result (7.258Å). Circular dichroism spectrum of metal-free 8 19 knot ligand was calculated and the maximum absorption in 262 nm, obtained was 67 L mol −1 cm −1 . These results are qualitatively similar to those obtained experimentally, 295 nm and 80 L mol −1 cm −1 , respectively. In this study, we report the electronic and molecular properties of the 8 19 ([Fe(II) 4 ]Cl and metal-free knot ligand complexes and compare with the results obtained from X-ray crystallographic data of 8 19 knot complex [Fe(II) 4 (PF 6 ) 7 ]Cl. The 8 19 knot were investigated by means of DFT, TD-DFT, and ONIOM approaches. Basis sets functions from all-electron for Br, I, and Fe atoms were adapted to be used along with relativistic effective core potential, while H, C, N, O, and Cl atoms were described by Pople basis sets. The objective was to understand the stability of the 8 19 knot as a function of the substitution of the central halogen atom (Cl), and the signal in the circular dichroism spectra. From the equilibrium geometries, we have obtained good results for values of the bond distance, bond angle, and dihedral angle along the molecular structure when these variables are compared with the results obtained from X-ray data. The diffusion effect of halogen into the 8 19 cavity, UV-Vis, and Electronic Circular Dichroism spectra was also analyzed. Circular dichroism spectrum of metal-free 8 19 knot ligand was calculated, and the maximum absorption is in good agreement with the experimental value. The ONIOM methodology combined with the relativistic effective core potential and the atomic basis sets provide good results for systems with a complex topology, such as knots.

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“…[3f] Since then,r esearch on helicates has expanded and diversified considerably.D evelopments include the utilization of helicatesa sb iomolecular probes, [4] as catalysts, [5] as molecular switches, [3a, 6] and as precursors for topologically complex molecular architectures. [7] Moreover,s ome helicates were found to display spin-crossover behavior [8] or act as single molecule magnets. [9] Helicatesh avea lso been investigated in a biological and medicinal context,l eading to the discover of complexes with cytotoxic, antiviral or antibacterial properties.…”

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confidence: 99%

Boronate Ester‐Capped Helicates

Giraldi

Depallens

Ortiz

et al. 2020

Chemistry A European J

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Triple‐stranded helicates were obtained by metal‐templated multicomponent reactions of bispyridyloxime ligands with arylboronic acids. The helicates feature two hexa‐coordinated MII ions (M=Fe, Zn, or Mn), which are embedded in a macrobicyclic ligand framework, and two arylboronate ester capping groups. The latter can be used to introduce functional groups such as pyridines, aldehydes, nitriles, and carboxylic acids in apical position. The functionalized helicates have the potential to be used as nanoscale building blocks for more complex assemblies, as evidenced by the synthesis of a 3 nm‐sized trianglimine.

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Molekulare Knoten

Cited by 64 publications

References 174 publications

A Hydrogen‐Bonded Ravel Assembled by Anion Coordination

A Hydrogen‐Bonded Ravel Assembled by Anion Coordination

819 molecular knot: a theoretical analysis of the electronic structure using an ONIOM approach

Boronate Ester‐Capped Helicates

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