‘Locking’ dendrimer conformation through metal coordination

Rauckhorst, Mark R.; Wilson, Paul; Hatcher, Susan A.; Hadad, Christopher M.; Parquette, Jon R.

doi:10.1016/s0040-4020(03)00460-5

Cited by 19 publications

(9 citation statements)

References 40 publications

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“…The group of Parquette studied the impact of metal coordination on the conformational properties of dendrimers by using small foldamers. [28] Their first efforts were to coordinate multiple Cu 2+ centers to pyridine-2,6-dicarboxamide dendrons that adopt compact helical conformations due to the syn-syn conformational preference of the pyridine-2,6-dicarboxamide repeat unit. [29] In these systems, the helical antipodes experience a highly dynamic equilibrium that interconverts the M and the P conformations rapidly with kinetic barriers too small to be measured by NMR spectroscopy.…”

Section: Metal Coordination In Folded Aromatic Amide Oligomersmentioning

confidence: 99%

Conformational Control in Metallofoldamers: Design, Synthesis and Structural Properties

Maayan

2009

Eur J Org Chem

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Metallofoldamers are sequence‐specific oligomers, which are designed to fold into three‐dimensional architectures upon metal coordination. Their folding can involve additional noncovalent interactions and results in new chiral secondary structures, enhanced stabilization of existing secondary structures, or unique materials for specific applications. This microreview highlights recent advances in the field.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Metal Coordination In Folded Aromatic Amide Oligomersmentioning

confidence: 99%

Conformational Control in Metallofoldamers: Design, Synthesis and Structural Properties

Maayan

2009

Eur J Org Chem

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“…Parquette et al have described intramolecularly hydrogen-bonded dendrimers showing a solvent-and temperature-dependent chiral conformational order. [21,22] The stability of the secondary structure was seen to be strongly influenced by the globular compaction of the dendrons. [23] In the absence of specific attractive or repulsive Abstract: The synthesis and metal complexation of chiral depsipeptide dendrimers 3 and 7 containing an ethylenediaminetetraacetic acid (EDTA) esterderived core is reported.…”

Section: Introductionmentioning

confidence: 99%

Metal‐Induced Chiral Folding of Depsipeptide Dendrimers

Buschhaus¹,

Hampel²,

Hirsch³

2005

Chemistry A European J

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The synthesis and metal complexation of chiral depsipeptide dendrimers 3 and 7 containing an ethylenediaminetetraacetic acid (EDTA) ester‐derived core is reported. The EDTA ester cavity of these dendrimers selectively complexes Zn2+ and Cu2+ ions leading to diastereoselective folding. To elucidate the coordination motif in the resulting “foldamers” of 3‐ZnCl2, 7‐ZnCl2, 3‐CuCl2, and 7‐CuCl2, the coordination behavior of the tetramethyl ester of EDTA (8) has been investigated as a model case. The corresponding complexes 8‐ZnCl2 and 8‐CuCl2 have been structurally characterized by 1H NMR spectroscopy and X‐ray analysis. The complexes involve the inherently chiral octahedral cis‐α coordination motif, in which 8 serves as a tetradentate ligand. In the case of the ZnII complex 8‐ZnCl2, both Δcis‐α(S,S,λ) and Λcis‐α(R,R,λ) stereoisomers were found in the unit cell. For the CuII complex 8‐CuCl2, only one stereoisomer, namely Δcis‐α(S,S,λ) was found in the crystal under investigation. 1H NMR spectroscopy has shown that the same coordination motif is diastereoselectively formed in the chiral Zn2+ dendrimers 3‐ZnCl2 and 7‐ZnCl2. Likewise, the calculated CD spectrum of the Δcis‐α(S,S,λ) stereoisomer of the model complex 8‐CuCl2 shows good agreement with the experimental spectrum of the CuII dendrimers 3‐CuCl2 and 7‐CuCl2, allowing assignment of the absolute configurations of the preferred foldamers as Λcis‐α(R,R,λ) for 3‐CuCl2 and Δcis‐α(S,S,λ) for 7‐CuCl2. This work represents the first example of metal‐complexation‐mediated diastereoselective folding of chiral dendrimers with known absolute configuration.

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“…This effect may be similar to the recently reported "kinetic lock" of the secondary structure of dendrons by metal coordination. 50…”

Section: Zinc(ii) Complexesmentioning

confidence: 99%

Copper(ii) and zinc(ii) ion binding properties of a MAP type branched ligand with histidines as surface functionalities

et al. 2009

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A novel branched peptide type ligand consisting of three lysines as branching units and four histidines as functional groups has been designed and prepared by solid phase peptide synthesis. The N-terminal histidines offer eight primary protonation/metal ion binding sites: four amino and four imidazole groups, capable of binding up to two metal ions. We examined the protonation equilibria, and the complex formation processes with copper(II) and zinc(II) ions in c(M):c(L) = 1:1 and 2:1 initial concentration ratio in aqueous solutions. The composition, speciation and the solution structure of the complexes have been determined by combined pH-potentiometric titrations, visible absorption, circular dichroism and NMR spectroscopy. In the case of both metal ions, mono- and dimetallic complexes formed with bis-histamine type coordination as the main species. While above pH 8 the precipitation of a neutral complex was observed for both metal ions, in the copper(II) containing systems it dissolved in alkaline solutions (pH > 11.0). The resulting complex in an equimolar system displays deprotonated amide-nitrogen coordination, with fused five-membered chelate rings around the metal ion in [CuLH(-3)](-). At the same time, only one copper(II) is able to coordinate in the same manner in the [Cu(2)LH(-5)](-) species. The second metal ion is probably surrounded by two amide nitrogens and two others either from amino or imidazole donor groups.

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‘Locking’ dendrimer conformation through metal coordination

Cited by 19 publications

References 40 publications

Conformational Control in Metallofoldamers: Design, Synthesis and Structural Properties

Conformational Control in Metallofoldamers: Design, Synthesis and Structural Properties

Metal‐Induced Chiral Folding of Depsipeptide Dendrimers

Copper(ii) and zinc(ii) ion binding properties of a MAP type branched ligand with histidines as surface functionalities

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