A5038594097- Porphyrin and Phthalocyanine Chemistry
- Supramolecular Chemistry and Complexes
- X-ray Diffraction in Crystallography
- Traditional and Medicinal Uses of Annonaceae
- Crystallization and Solubility Studies
- Biological Activity of Diterpenoids and Biflavonoids
- Phytochemistry and Biological Activities
- Photosynthetic Processes and Mechanisms
- Metal-Catalyzed Oxygenation Mechanisms
- Photoreceptor and optogenetics research
- Seed and Plant Biochemistry
- Oxidative Organic Chemistry Reactions
- Bioactive natural compounds
- Hemoglobin structure and function
- Photochromic and Fluorescence Chemistry
- Natural product bioactivities and synthesis
- Molecular Sensors and Ion Detection
- Mass Spectrometry Techniques and Applications
- Surface Chemistry and Catalysis
- Medicinal plant effects and applications
- Phytochemical compounds biological activities
- CO2 Reduction Techniques and Catalysts
- Plant biochemistry and biosynthesis
- African Botany and Ecology Studies
- Cocoa and Sweet Potato Agronomy
Radboud University Nijmegen
2017-2024
Radboud Institute for Molecular Life Sciences
2020-2024
Radboud University Medical Center
2020-2024
University of Groningen
2022
Aix-Marseille Université
2022
Covalent organic frameworks (COFs) are ideal platforms to spatially control the integration of multiple molecular motifs throughout a single nanoporous framework. Despite this design flexibility, COFs typically synthesized using only two monomers. One bears functional motif for envisioned application, while other is used as an inert connecting building block. Integrating more than one extends functionality immensely, which particularly useful multistep reactions such electrochemical...
Abstract Porphyrin cage-compounds are used as biomimetic models and substrate-selective catalysts in supramolecular chemistry. In this work we present the resolution of planar-chiral porphyrin cages determination their absolute configuration by vibrational circular dichroism combination with density functional theory calculations. The chiral porphyrin-cages form complexes achiral viologen-guests upon binding one axial enantiomorphs guest is bound selectively, indicated...
Abstract Molecular motors and switches change conformation under the influence of an external stimulus, e.g. light. They can be incorporated into functional systems, allowing construction adaptive materials switchable catalysts. Here, we present two molecular motor-functionalized porphyrin macrocycles for future photo-switchable catalysis. display helical, planar point chirality, are diastereomers, which differ in relative orientation motor macrocyclic components. Fluorescence, UV-vis, 1 H...
Here we describe a photoswitchable iron(III) salen phosphate catalyst, which is able to catalyze the enantiodivergent oxidation of prochiral aryl alkyl sulfides chiral sulfoxides. The stable (S)-axial isomer catalyst produced enantioenriched sulfoxides with (R)-configuration in up 75 % e.e., whereas photoisomerized metastable (R)-axial favored formation (S)-sulfoxides 43 e.e. maximum Δe.e. value obtained sulfoxidation was 118 %, identical that measured epoxidation alkenes by related recently...
An improved and scalable synthetic route to chiral porphyrin cage compounds, which will be used as catalytic machines for the encoding of information into polymers, has been developed. The was made by introducing one or two nitro groups on its xylylene sidewalls. This nitration performed with fuming nitric acid at low temperature occurred in a highly regioselective fashion. latter thought result binding nitronium cation inside cavity compound, directing reaction However, 1H NMR titrations...
We present a mild way of converting secondary methyl ethers into ketones using calcium hypochlorite in aqueous acetonitrile with acetic acid as activator. The reaction is compatible various oxygen- and nitrogen-containing functional groups afforded the corresponding up to 98% yield. use this methodology could expand application group useful protecting group.
Two new biflavanones (1 and 2), three bichalconoids (3–5), 11 known flavonoid analogues (6–16) were isolated from the stem bark extract (CH3OH–CH2Cl2, 7:3, v/v) of Ochna holstii. The structures metabolites elucidated by NMR spectroscopic mass spectrometric analyses. crude evaluated for antibacterial activity against Bacillus subtilis (Gram-positive) Escherichia coli (Gram-negative) as well cytotoxicity MCF-7 human breast cancer cell line. holstiinone A (1) exhibited moderate B. with MIC...
The construction of macromolecular hosts that are able to thread chiral guests in a stereoselective fashion is big challenge. We herein describe the asymmetric synthesis two enantiomeric C 2-symmetric porphyrin macrocyclic and bind different viologen guests. Time-resolved fluorescence studies show these display factor 3 kinetic preference (ΔΔG ‡ on = kJ mol-1) for threading onto enantiomers guest appended with bulky 1-phenylethoxy termini. A smaller selectivity 1 observed viologens equipped...
Five new cyclohexene derivatives, dipandensin A and B (1 2) pandensenols A–C (3–5), 16 known secondary metabolites (6–21) were isolated from the methanol-soluble extracts of stem root barks Uvaria pandensis. The structures characterized by NMR spectroscopic mass spectrometric analyses, that 6-methoxyzeylenol (6) was further confirmed single-crystal X-ray crystallography, which also established its absolute configuration. evaluated for antibacterial activity against Gram-positive bacteria...
Macrocyclic metal porphyrin complexes can act as shape-selective catalysts mimicking the action of enzymes. To achieve enzyme-like reactivity, a mechanistic understanding reaction at molecular level is needed. We report study alkene epoxidation by oxidant iodosylbenzene, mediated an achiral and chiral manganese(V)oxo cage complex. Both convert great variety alkenes into epoxides in yields varying between 20-88 %. monitored process formation oxygen transfer from iodosylbenzene to...
The new isoflavonoid kirkinone A (1) and biflavonoid B (2) along with six known compounds (3–8) were isolated from the methanolic extract of root bark Ochna kirkii. identified by NMR spectroscopic mass spectrometric analyses. Out eight natural products, calodenin (4) lophirone (6) showed significant antibacterial activity against Gram-positive bacterium Bacillus subtilis MIC values 2.2 28 μM, cytotoxicity MCF-7 human breast cancer cell line EC50 219.3 19.2 respectively. crude exhibited at...
Abstract Chiral zirconium(IV) double cage sandwich complex Zr(1) 2 has been synthesized in one step from porphyrin H 1. was obtained as a racemate, which resolved by HPLC and the enantiomers were isolated >99.5 % ee. Their absolute configurations assigned on basis of X‐ray crystallography circular dichroism spectroscopy. Vibrational (VCD) experiments revealed that chirality around zirconium center is propagated throughout whole structure. The axial conformational displayed VCD fingerprint...
The kinetic enantio-recognition of chiral viologen guests by planar-chiral porphyrin cage compounds, measured in terms ΔΔG‡on, is determined the planar-chirality host and influenced size, as ion mobility-mass spectrometry, but not chirality its substituents.
The CH2Cl2/MeOH (1:1) extract of the stems Tephrosia uniflora yielded new β-hydroxydihydrochalcone (S)-elatadihydrochalcone-2'-methyl ether (1) along with three known compounds elongatin (2), (S)-elatadihydrochalcone (3), and tephrosin (4). structures were elucidated by NMR spectroscopic mass spectrometric data analyses. Elongatin (2) showed moderate antibacterial activity (EC50 25.3 μM EC90 32.8 μM) against Gram-positive bacterium Bacilus subtilis, comparable toxicity MCF-7 human breast...
Abstract Molecular motors change conformation under the influence of light and when attached to host molecules, they may find applications as sensors switchable catalysts. Here, we present a porphyrin macrocyclic functionalized with two motor appendages for future catalytic applications. The compound is formed mixture six stereoisomers (three sets enantiomers), which have been separated by (chiral) chromatography. 1 H NMR chiral spectroscopy revealed that in one set enantiomers, interact...
Abstract The development of enantio-divergent catalysts capable producing in a controlled fashion each the two enantiomeric products from one substrate, is highly challenging. It requires implementation switching function into catalyst, which can reversibly change chiral reaction environment during catalysis. Here we report photo-switchable phosphate ligand derived 2,2’-biphenol, axially coordinates as counter ion to an achiral manganese(III) salen providing latter with ability dynamically...
The CH2Cl2/MeOH (1:1) extract of the stems Tephrosia uniflora yielded new β-hydroxydihydrochalcone (S)-elatadihydrochalcone-2'-methyl ether ( 1 ) along with three known compounds elongatin (2), (S)-elatadihydrochalcone (3), and tephrosin (4). structures were elucidated by NMR spectroscopic mass spectrometric data analyses. major constituent 2 showed moderate antibacterial activity (EC50 25.0 μM EC90 33.0 µM) against Gram-positive bacterium Bacilus subtilis , comparable toxicity MCF-7 human...