Search results for "Picolinic acid"
showing 7 items of 7 documents
Stimuli-responsive bile acid-based metallogels forming in aqueous media
2015
Abstract The synthesis and gelation properties of a picolinic acid conjugated bile acid derivative in the presence of metal salts along with the stimuli-responsiveness of the systems are reported. The gels are formed in the presence of Cu 2+ ions in the solvent systems composed of 30–50% of organic solvent (MeOH, acetonitrile, or acetone) in water. The gels respond to various stimuli: they can be formed upon sonication or shaking, and their gel–sol transformation can be triggered by a variety of chemical species. NMR, MS, and SEM techniques are exploited in order to gain a deeper insight on the self-assembled systems.
Label-Free Pyrophosphate Recognition with Functionalized Asymmetric Nanopores
2016
[EN] The label¿free detection of pyrophosphate (PPi) anions with a nanofluidic sensing device based on asymmetric nanopores is demonstrated. The pore surface is functionalized with zinc complexes based on two di(2¿picolyl)amine [bis(DPA)] moieties using carbodiimide coupling chemistry. The complexation of zinc (Zn2+) ion is achieved by exposing the modified pore to a solution of zinc chloride to form bis(Zn2+¿DPA) complexes. The chemical functionalization is demonstrated by recording the changes in the observed current¿voltage (I¿V) curves before and after pore modification. The bis(Zn2+¿DPA) complexes on the pore walls serve as recognition sites for pyrophosphate anion. The experimental re…
Single-molecule magnetic behavior in a neutral terbium(III) complex of a picolinate-based nitronyl nitroxide free radical
2011
The terdentate anionic picolinate-based nitronyl nitroxide (picNN) free radical forms neutral and robust homoleptic complexes with rare earth-metal ions. The nonacoordinated Tb3+ complex Tb(picNN)3• 6H2O is a single-molecule magnet with an activation energy barrier Δ = 22.8 ± 0.5 K and preexponential factor τ0 = (5.5 ± 1.1) × 10-9 s. It shows magnetic hysteresis below 1 K. © 2011 American Chemical Society.
Copper(II)-dipicolinate-mediated clickable azide–alkyne cycloaddition in water as solvent
2018
Copper(II)-dipicolinate complex [CuIIL(H2O)2] (1) (H2L = dipicolinic acid (H2dipic)) was synthesized via oxidation of copper(I) iodide and pyridine-2,6-dicarboxylic acid in water and acetonitrile in the presence of glycine. Complex 1 was characterized by FT-IR and elemental analysis and its structure confirmed by single crystal X-ray analysis. This complex is an efficient precatalyst that mediates azide-alkyne cycloaddition reactions in water at room temperature either in the absence or presence of a reducing agent. Compound 1-mediated azide-alkyne cycloaddition affords alkyl/aryl substituted 1,2,3-triazole heterocycles in a regioselective manner and excellent yields under very mild reactio…
UV resistance of Bacillus subtilis spores - Involvement of DPA and characterization by photonic microscopy
2022
The aim of this project was to study the UVc resistance of Bacillus subtilis spores. The first part of this project focused on the dipicolinic acid molecule (DPA) which is known to be involved in the UV resistance of spores. However, some points remain unresolved. In particular, it is known that this molecule forms fluorescent photoproducts (DPAp), which were not identified at the beginning of this project. No information concerning the role of these DPAp in UVC resistance was available at that time. During this project, a protocol was established to follow the appearance of these photoproducts directly inside the spore core. A method was also set up to artificially introduce DPAp into the …
Pyridinedicarboxylates, the first mechanism-derived inhibitors for prolyl 4-hydroxylase, selectively suppress cellular hydroxyprolyl biosynthesis. De…
1987
Two pyridinedicarboxylates, predicted [Hanauske-Abel (1983) M.D.-Ph.D. Thesis, Philipps Universität Marburg] and later found to be potent reversible inhibitors of purified prolyl 4-hydroxylase [Majaama, Hanauske-Abel, Günzler & Kivirikko (1984) Eur. J. Biochem. 138, 239-245] were investigated with respect to their effect on hydroxyprolyl biosynthesis in the fibroblast/collagen and the macrophage/Clq systems, and the effect was compared with that of the iron chelator 2,2′-dipyridyl, the compound usually employed to inhibit cellular hydroxyprolyl formation. Only the enzyme-mechanism-derived pyridinedicarboxylates were highly selective inhibitors, and only they lacked overt cytotoxicity. M…
Thiphenylmethane based structural fragments as building blocks towards solution-processable heteroleptic iridium(iii) complexes for OLED use
2019
A novel structural approach to solution-processable heteroleptic iridium(III) complexes is presented. On the basis of 2-arylbenzo[d]thiazole cyclometalating main ligands and picolinic acid (pic) and acetylacetone (acac) ancillary ligands six new yellow or orange emitting materials were obtained using attached 1,1,1-triphenylmethylpentane substituents as aggregation preventing and solubility enhancing functional fragments. The obtained compounds show high photoluminescence quantum yield values in the range of 0.64 to 0.90. OLEDs with a spin-coated emissive layer were successfully prepared, with the highest achieved external quantum efficiency of 7.9%, current efficiency of 12.4 cd A−1 and po…