Tri-ionizable calix[4]arene ligands: synthesis and lanthanide ion complexation

Fernandez, Fernando A.; Bartsch, Richard A.; Arnaud‐Neu, Françoise; Hubscher-Bruder, Véronique; Michel, Sylvie

doi:10.3998/ark.5550190.0011.715

Cited by 6 publications

(2 citation statements)

References 14 publications

(20 reference statements)

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“…The La−O and La−N distances range from 2.156 to 2.555 Å, typical for La(III) complexes with a N 2 O 6 environment [21a] . Only few examples of lanthanide complexes with three‐armed calix[4]arenes have been characterized [29,30] …”

Section: Resultsmentioning

confidence: 99%

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Synthesis, structures and optical properties of mononuclear La, Eu and Tb complexes supported by calix[4]arene ligands bearing three pendant salicylaldiminato arms

Günzel,

Börner,

Kersting

2023

Zeitschrift anorg allge chemie

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The synthesis and complexation behaviour of a new calix[4]arene ligand H4L3 bearing three pendant salicylaldimine arms towards selected lanthanide ions has been investigated. Reaction of H4L3 with Ln(NO3)3⋅6H2O in MeOH in the presence of NEt3 provides monomeric complexes of composition [Ln(HL3)] (Ln=La3+ (4), Eu3+ (5), Tb3+ (6)). An X‐ray crystallographic analysis for 4 reveals that only two of the three ligand arms are involved in the coordination of the lanthanide ions, to give eight‐coordinated Ln3+ ions in a distorted square‐antiprismatic N2O6 environment. UV‐vis spectrophotometric titrations show that such monomeric species prevail in CH2Cl2/MeOH (1/1 v/v) solution. The apparent stability constants determined by UV‐vis spectrophotometric titration are log K=6.8(2) for 5 and log K=5.8(1) for 6. The Eu and Tb complexes luminesce only weakly at 77 K with luminescence lifetimes of 0.469 and 0.306 s.

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Section: Resultsmentioning

confidence: 99%

“…[21a] Only few examples of lanthanide complexes with three-armed calix [4]arenes have been characterized. [29,30]…”

Section: Synthesis and Characterization Of Compoundsmentioning

confidence: 99%

Synthesis, structures and optical properties of mononuclear La, Eu and Tb complexes supported by calix[4]arene ligands bearing three pendant salicylaldiminato arms

Günzel,

Börner,

Kersting

2023

Zeitschrift anorg allge chemie

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One‐Step Catalytic Enantioselective α‐Quaternary 5‐Hydroxyproline Synthesis: An Asymmetric Entry to Highly Functionalized α‐Quaternary Proline Derivatives

Breistein¹,

Johansson²,

Ibrahem³

et al. 2012

Adv Synth Catal

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The highly enantioselective cascade reaction between N‐protected α‐cyanoglycine esters and α,β‐unsaturated aldehydes is disclosed. The reaction represents a one‐step entry to polysubstituted 5‐hydroxyproline derivatives having a quaternary α‐stereocenter generally in high yields with up to >95:5 dr and 99:1 er. It is also a direct catalytic two‐step entry to functionalized α‐quaternary proline derivatives.

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Synthesis and Conformational Study of Model Peptides Containing N‐Substituted 3‐Aminoazetidine‐3‐carboxylic Acids

et al. 2014

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Model peptides containing N‐substituted 3‐aminoazetidine‐3‐carboxylic acids have been synthesized to investigate the conformational features of these Cα‐tetrasubstituted amino acids. The target peptides were designed and prepared by classical synthetic methods in solution, exploiting the convenient N‐substituted 3‐azidoazetidine‐3‐carboxylic acids as precursors. The conformational preferences of the newly synthesized peptides were investigated in solution by IR and NMR spectroscopy. It was observed that the 3‐aminoazetidine‐3‐carboxylic acid moiety is likely a β‐turn inducer. In addition, an interesting main‐chain‐to‐side‐chain hydrogen bond that forms a six‐membered pseudo‐cycle was detected. It connects the nitrogen (acceptor) of the azetidine ring to the amide NH (donor) of the immediately following residue. This unexpected hydrogen bond increases the number of conformational options offered by N‐substituted 3‐aminoazetidine‐3‐carboxylic acids when designing foldamers with new and predictable 3D structures.

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Tri-ionizable calix[4]arene ligands: synthesis and lanthanide ion complexation

Cited by 6 publications

References 14 publications

Synthesis, structures and optical properties of mononuclear La, Eu and Tb complexes supported by calix[4]arene ligands bearing three pendant salicylaldiminato arms

Synthesis, structures and optical properties of mononuclear La, Eu and Tb complexes supported by calix[4]arene ligands bearing three pendant salicylaldiminato arms

One‐Step Catalytic Enantioselective α‐Quaternary 5‐Hydroxyproline Synthesis: An Asymmetric Entry to Highly Functionalized α‐Quaternary Proline Derivatives

Synthesis and Conformational Study of Model Peptides Containing N‐Substituted 3‐Aminoazetidine‐3‐carboxylic Acids

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