Search results for "Thioether"
showing 6 items of 36 documents
Diorganotin(IV) dipeptide complexes with potential antitumour activity
1993
A series of complexes of the dimethylltin(IV) moiety with dipeptides has been synthesized. The dipeptides are L-alanyl-L-histidine (H2AlaHis), L-methionyl-L-methionine (H2MetMet), L-glycyl-L-histidine (H2GlyHis) and L-histidyl-L-glycine (H2HisGly). The complexes have been characterized by IR and 119Sn Mossbauer spectroscopy in the solid state and by 1H NMR in CD3OD and D2O solutions. They consist of monomeric entities, with the tin atom arranged in a pentacoordinated trigonal bipyramidal structure. The dipeptides are coordinated via the amino group, deprotonated peptide nitrogen and carboxylate group. Neither imidazole in histidine-containing dipetides, nor the thioether group in MetMet, is…
Transient Hydrogels Mediated by Redox-Switchable Supramolecular Polymerization
2017
Spatial and temporal control in multi-stimuli-responsive materials are critical properties to advance and optimize functional soft matter in order to mimic key features of living systems. In this contribution, I will discuss our methodology in developing non-equilibrium states in supramolecular materials. We have expanded our concept of charge regulated s–sheet self-assembly of alternating hydrophilic and hydrophobic amino acids in order to introduce redox-switchable properties. An interplay of pH- and oxidation-stimuli, promoted by the production of reactive oxygen species (ROS) thus leads to transient supramolecular polymerizations of methionine containing amphiphiles, with tuneable lifet…
Selective Gold Recovery and Catalysis in a Highly Flexible Methionine-Decorated Metal–Organic Framework
2016
A novel chiral 3D bioMOF exhibiting functional channels with thio-alkyl chains derived from the natural amino acid l-methionine (1) has been rationally prepared. The well-known strong affinity of gold for sulfur derivatives, together with the extremely high flexibility of the thioether "arms" decorating the channels, account for a selective capture of gold(III) and gold(I) salts in the presence of other metal cations typically found in electronic wastes. The X-ray single-crystal structures of the different gold adsorbates Au(III)@1 and Au(I)@1 suggest that the selective metal capture occurs in a metal ion recognition process somehow mimicking what happens in biological systems and protein r…
Spectroscopic characterization and biological activity ofL-methionyl-L histidinato complexes of R2Sn(IV) ions (R?=?Me, nBu, Ph) and X-ray structure o…
2000
Complexes of L-methionyl-L-histidine (H2MetHis) with R2Sn(IV) ions (R = Me, nBu, Ph) have been synthesized. The crystal and molecular structures of Me2SnMetHis·0.5MeOH have been determined by X-ray diffraction. The title compound contains two crystallographically independent molecular units possessing the same trigonal-bipyramidal geometry at tin, each dimethyltin(IV) moiety being coordinated by the terminal amino nitrogen, deprotonated peptide nitrogen and terminal carboxylate group, neither the imidazole nor thioether groups being involved in bonding. IR spectroscopy was used to probe the structure of the complexes in the solid state, and the structure in solution (CD3OD) was assessed by …
Synthesis of new hybrid 1,4-thiazinyl-1,2,3-dithiazolyl radicals via Smiles rearrangement
2017
The condensation reaction of 2-aminobenzenethiols and 3-aminopyrazinethiols with 2-amino-6-fluoro-N-methylpyridinium triflate afforded thioether derivatives that were found to undergo Smiles rearrangement and cyclocondensation with sulphur monochloride to yield new hybrid 1,4-thiazine-1,2,3-dithiazolylium cations. The synthesized cations were readily reduced to the corresponding stable neutral radicals with spin densities delocalized over both 1,4-thiazinyl and 1,2,3-dithiazolyl moieties. peerReviewed
Oxidation-responsive and "clickable" poly(ethylene glycol) via copolymerization of 2-(methylthio)ethyl glycidyl ether
2016
Poly(ethylene glycol) (PEG) is a widely used biocompatible polymer. We describe a novel epoxide monomer with methyl-thioether moiety, 2-(methylthio)ethyl glycidyl ether (MTEGE), which enables the synthesis of well-defined thioether-functional poly(ethylene glycol). Random and block mPEG-b-PMTEGE copolymers (Mw/Mn = 1.05-1.17) were obtained via anionic ring opening polymerization (AROP) with molecular weights ranging from 5 600 to 12 000 g·mol-1. The statistical copolymerization of MTEGE with ethylene oxide results in a random microstructure (rEO = 0.92 ± 0.02 and rMTEG E = 1.06 ± 0.02), which was confirmed by in situ 1H NMR kinetic studies. The random copolymers are thermorespon…