Preparation of Resolved Fourfold Symmetric Amphiphilic Helices Using Chiral Metallacrown Building Blocks

Noord, Annabel D. Cutland-Van; Kampf, Jeff W.; Pecoraro, Vincent L.

doi:10.1002/ange.200290009

Cited by 17 publications

(4 citation statements)

References 29 publications

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“…X-ray crystal structures have been determined for a series of {Ln III (NO 3 ) 3- x [15-MC Cu II N(S-pheHA) -5](OH) x },where Ln III = La III , Nd III , Sm III , Eu III , Gd III , Tb III , and Ho III and x = 0, 1, or 1.5, allowing the effects of the lanthanide ion radius on the metallacrown structure to be determined . For the lanthanide ions investigated, the ionic radius varies from 1.16 Å for La III to 1.02 Å for Ho III for eight-coordinate species …”

Section: 6 15-mc-5mentioning

confidence: 99%

“…Planar Gd III [15-MC Cu II -5] complexes made with both chiral and achiral ligands have been tested for their ability to behave as MRI contrast agents. ,, Proton relaxivity measurements indicate that the Gd III [15-MC-5] complexes have higher relaxivity values than Gd III -DOTA and Gd III -DTPA, the standards upon which new MRI contrast agents are compared . However, many more studies are required before clinical applications can be fully assessed.…”

Section: 6 15-mc-5mentioning

confidence: 99%

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Structural and Functional Evolution of Metallacrowns

2007

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Section: 6 15-mc-5mentioning

confidence: 99%

Section: 6 15-mc-5mentioning

confidence: 99%

Structural and Functional Evolution of Metallacrowns

2007

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“…Each MS spectrum (right) corresponds to the chromatogram (left) of the same sample. A,a, B,b – crude products containing 15 amino acid residues; C,c, D,d – fragment of Peptide 1; E,e, F,f – fragment of Peptide 1.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, there has been an increasing interest in formation of supramolecular structures by various derivatives of hydroxamic acids, especially aminohydroxamic acids. The literature data illustrate the examples of metallacrowns – the structures formed by 4 hydroxamates and 5 copper (II) ions . These complexes are formed by α , β and γ ‐aminohydroxamic acids .…”

Section: Introductionmentioning

confidence: 99%

Solid phase synthesis of peptide hydroxamic acids on poly(ethylene glycol)‐based support

Cal

Jaremko

et al. 2012

Journal of Peptide Science

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Supramolecular Helix‐to‐Helix Induction: A 3D Anionic Framework Containing Double‐Helical Strands Templated by Cationic Triple‐Stranded Cluster Helicates

Hou

et al. 2008

Angewandte Chemie

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Linked historically to the discovery of the double-helical structure of DNA by Watson and Crick [1a] and the introduction of the first inorganic double-stranded helicate by Lehn et al., [1b] artificial molecular multiple-stranded helices are at the frontier for synthetic chemists in the field of organic, inorganic, and supramolecular chemistry. [2] In the realm of coordination chemistry, artificial helical assemblies, including discrete helicates [3] and infinite helices, [4] are attracting increasing attention. The helicate series has been systematically and intensively investigated, [3a] mostly relying on intramolecular coordinative bonds to construct discrete multiplestranded helicates. However, a potential approach is to selfassemble supramolecular multiple-helical structures using intermolecular noncovalent interactions, such as electrostatic interactions, hydrogen bonding, and p stacking. [2a,d, 3a] Therefore, a judicious strategy is desired for constructing functional helical coordination polymers through transfer of intrinsic structural information from noncovalent interactions with discrete helicates.Inspired by well-defined discrete molecular helicates, [3a] we propose herein a helix-to-helix induction strategy to fabricate supramolecular polymeric helices using helicates as templates. We have previously developed a sulfur-transformation approach [5] to construct supramolecular aggregates of anionic CuSCN/CuCN networks directed by cationic metalbis(terpyridine) monomers.[5d] In this work, cationic cluster helicates [6] were selected to implement the helix-to-helix induction because: 1) the well-shaped cluster possesses intriguing helical character, thereby making the template effect [7,8] feasible; 2) the cluster is positively charged and should show strong electrostatic interactions with the negatively charged inorganic framework; 3) there may exist hydrogen bonding between the encapsulating inorganic components and the wrapped ligands of the cluster helicates, which carry abundant hydrogen atoms.The ligand 3,5-bis(2-pyridyl)pyrazole (HL), synthesized through similar reactions as in our previous work, [9] Complex 2 a (or 2 b) could also be obtained solvothermally in acetonitrile by the one-pot reaction of CuSCN, Ni 2+ (or Zn 2+ ) salt, HL, and PPh 3 (Scheme 1). The fact that the same polymeric helices (2) could be synthesized in one-pot reactions suggests that the helicate templates (1) may be generated and stay stable before the encapsulation of the inorganic components in the solvothermal conditions.[5c]X-ray crystallographic analysis [10] reveals that 1 a and 1 b as well as 2 a and 2 b are isostructural, and therefore only 1 a and 2 a are discussed in detail. The structure of the triplestranded helicate 1 a can be viewed as a [Ni 3 (m-OH)] 5+ cluster core wrapped by two terminal [Ni(m-L) 3 ] À units, [6b] and the whole tricationic helicate is balanced by SCN À ions. In the crystal packing left-handed (Figure 1, middle-up) and righthanded (Figure 1, middle-down) triple-stranded helica...

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Preparation of Resolved Fourfold Symmetric Amphiphilic Helices Using Chiral Metallacrown Building Blocks

Cited by 17 publications

References 29 publications

Structural and Functional Evolution of Metallacrowns

Structural and Functional Evolution of Metallacrowns

Solid phase synthesis of peptide hydroxamic acids on poly(ethylene glycol)‐based support

Supramolecular Helix‐to‐Helix Induction: A 3D Anionic Framework Containing Double‐Helical Strands Templated by Cationic Triple‐Stranded Cluster Helicates

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