A5023760545- Molecular spectroscopy and chirality
- Spectroscopy and Quantum Chemical Studies
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Analytical Chemistry and Chromatography
- DNA and Nucleic Acid Chemistry
- Neonatal Health and Biochemistry
- Porphyrin and Phthalocyanine Chemistry
- Protein Interaction Studies and Fluorescence Analysis
- Protein Structure and Dynamics
- Molecular Sensors and Ion Detection
- Axial and Atropisomeric Chirality Synthesis
- Heme Oxygenase-1 and Carbon Monoxide
- Hemoglobin structure and function
- Crystallography and molecular interactions
- Chemical Synthesis and Analysis
- Photosynthetic Processes and Mechanisms
- Gold and Silver Nanoparticles Synthesis and Applications
- Carbohydrate Chemistry and Synthesis
- Supramolecular Self-Assembly in Materials
- Phytochemistry and Biological Activities
- Photoreceptor and optogenetics research
- Bioactive natural compounds
- Synthesis and Properties of Aromatic Compounds
- Molecular Spectroscopy and Structure
University of Chemistry and Technology, Prague
2011-2024
Institute of Chemical Technology
2012-2016
University of Veterinary Sciences Brno
2008-2010
Czech Academy of Sciences, Institute of Experimental Botany
2010
University of Padua
2010
Palacký University Olomouc
2010
Comenius University Bratislava
2009
Czech University of Life Sciences Prague
2008
Masaryk University
2001-2008
Centre National de la Recherche Scientifique
2008
Gold nanoparticles with shape-determined chirality enable the attainment of plasmon-associated optical activities exceeding those exhibited by all previously known natural objects. These nanoparticles, together their subdiffraction light focusing and excitation chiral, plasmon-related near-fields, offer a range very interesting applications. Herein, we propose use these chiral plasmon for asymmetric organic catalysis implementation optically active probes (alkoxyamines). Plasmon triggering...
The development of density functional theory (DFT) methods for the calculation vibrational circular dichroism (VCD), electronic (ECD), and transparent spectral region optical rotation (OR) has revolutionized determination absolute configurations (ACs) chiral molecules using these chiroptical properties. We report first concerted application DFT calculations VCD, ECD, OR to AC a natural product whose was previously undetermined. is alkaloid schizozygine, isolated from Schizozygia caffaeoides....
The infrared (IR) and vibrational circular dichroism (VCD) spectra of S-2,2'-dimethyl-biphenyl-6,6'-dicarboxylic acid, S-1, in CDCl(3) solution are concentration-dependent, showing that oligomerization occurs with increasing concentration. DFT calculations support the conclusion oligomer formed is cyclic tetramer (S-1)(4), which S-1 monomers linked by hydrogen(H)-bonded (COOH)(2) moieties. Due to existence two inequivalent tautomeric conformations each moiety, six (S-1)(4) possible....
Chiroptical techniques are increasingly employed for assigning the absolute configuration of chiral molecules through comparison experimental spectra with theoretical predictions. For assignment natural products, electronic chiroptical spectroscopies such as circular dichroism (ECD) routinely applied. However, sensitivity spectral parameters to conditions and methods can lead incorrect assignments. Vibrational (vibrational dichroism, VCD, Raman optical activity, ROA) provide more reliable...
Nine geranylated flavanones isolated from the fruits of Paulownia tomentosa (4−12) and two roots Morus alba (13 14) were examined for cytotoxicity to selected human cancer cell lines normal fibroblasts. Cytotoxicity was determined in vitro using a calcein AM assay. THP-1 monocytic leukemia line tested erythrosin B staining. The compounds compared with known simple flavanone standards taxifolin (1), naringenin (2), hesperetin (3) standard anticancer drugs olomoucine II, diaziquone,...
Increasing precision of contemporary computational methods makes spectroscopies such as vibrational (VCD) and electronic (ECD) circular dichroism attractive for determination absolute configurations (AC) organic compounds. This is, however, difficult polar, flexible molecules with multiple chiral centers. Typically, a combination several provides the best picture molecular behavior. As test case, all possible stereoisomers known AC (RS, SR, SS, RR) cyclic dipeptide cyclo(Arg-Trp) (CAT) were...
Distinct advantages of surface enhanced Raman scattering (SERS) in molecular detection can benefit the enantioselective discrimination specific configurations. However, many recent methods still lack versatility and require customized anchors to chemically interact with studied analyte. In this work, we propose utilization helicoid-shaped chiral gold nanoparticles arranged an ordered array on a grating for SERS recognition. This arrangement ensured homogeneous distribution plasmonic hot...
Absorption and vibrational circular dichroism (VCD) spectra of six 1,1'-binaphthyl derivatives were measured analyzed on the basis ab initio modeling. The both enantiomers recorded with a high signal-to-noise ratio. BPW91/6-31G** density functional theory level gauge invariant atomic orbitals used for simulations VCD intensities. binaphthyl moiety behaves as chiral chromophore strong signal because 1,1'-substitution hinders its rotation. Most bands assigned, contributions skeleton groups...
Abstract This work provides a systematic comparison of vibrational CD (VCD) and electronic (ECD) methods for spectral prediction secondary structure. The VCD ECD data are simplified to small set parameters using the principal component method factor analysis (PC/FA). Regression fits these made X‐ray‐determined fractional components ( FC ) Predictive capability is determined by computing structures proteins sequentially left out regression. All possible combinations PC/FA (coefficients) were...
Eight C-6-geranylflavonoids (1−8) were isolated from an ethanol extract of Paulownia tomentosa fruits. Tomentodiplacone (1), 3′-O-methyl-5′-hydroxydiplacone (2), 3′-O-methyl-5′-O-methyldiplacone (3), and tomentodiplacone B (4) obtained as new compounds, 3′-O-methyldiplacol (5) was for the first time a natural source. The structures these compounds determined by using mass spectrometry (including HRMS) 1D 2D NMR spectroscopy, absolute configurations circular dichroism. antibacterial...
Helically chiral styryl dyes with large ECD in the visible region are introduced.
Abstract The development of density functional theory (DFT) methods for the calculation vibrational circular dichroism (VCD), electronic (ECD), and transparent spectral region optical rotation (OR) has revolutionized determination absolute configurations (ACs) chiral molecules using these chiroptical properties. We report concerted application DFT calculations VCD, ECD, OR to ACs isoschizozygane alkaloid natural products, isoschizogaline, isochizogamine, whose have not previously been...
The self-assembly of guanosine-5'-hydrazide G-1 in D(2)O, the presence and absence sodium cations, has been investigated by chiroptical techniques: electronic (ECD) newly introduced vibrational (VCD) circular dichroism spectroscopy. Using a combination ECD VCD with other methods such as IR, electron microscopy, electrospray ionization mass spectrometry (ESI-MS) it was found that produces long-range chiral aggregates consisting G-quartets, (G-1)(4), subsequently stacked into columns,...
The N-terminus of the B-chain insulin may adopt two alternative conformations designated as T- and R-states. Despite recent structural insight into insulin–insulin receptor (IR) complexes, physiological relevance T/R transition is still unclear. Hence, this study focused on rational design, synthesis, characterization human analogues structurally locked in expected R- or T-states. Sites B3, B5, B8, capable affecting conformation B-chain, were subjects substitutions with amino acids specific...
Two new isoquinoline alkaloids, named fumaranine (2) and fumarostrejdine (10), along with 18 known alkaloids were isolated from aerial parts of Fumaria officinalis. The structures the compounds elucidated on basis spectroscopic analyses by comparison literature data. absolute configuration compound 2 was determined comparing its circular dichroism spectra those analogs. Compounds in sufficient amounts evaluated for their acetylcholinesterase, butyrylcholinesterase, prolyl oligopeptidase...
Although phototherapy was introduced as early 1950's, the potential biological effects of bilirubin photoisomers (PI) generated during remain unclear. The aim our study to isolate PI in their pure forms and assess vitro. three major (ZE- EZ-bilirubin Z-lumirubin) were prepared by photo-irradiation unconjugated bilirubin. individual photoproducts chromatographically separated (TLC, HPLC), identities verified mass spectrometry. role Z-lumirubin (the principle PI) on dissociation from albumin...
Abstract Chiral nanophotonic platforms provide a means of creating near fields with both enhanced asymmetric properties and intensities. They can be exploited for optical measurements that allow enantiomeric discrimination at detection levels > 6 orders magnitude than is achieved conventional chirally sensitive spectroscopic methods based on circularly polarized light. Here it shown surface Raman spectroscopy (SERS) such local probe the field environment. It used to achieve chiral...
The infrared (IR) and vibrational circular dichroism (VCD) spectra of guanosine-5′-hydrazide (G-1), a powerful hydrogelator, have been measured analyzed on the basis ab initio modeling. B3LYP/6-31G** DFT calculations predict that G-1, forming clear solution in deuterated DMSO, is present monomeric form this solvent, whereas strong gelation phosphate buffer due to formation guanine-quartet structure, (G-1)4, which four G-1 are linked by hydrogen-bonded guanine moieties stabilized an alkali...
A dicationic [6]helicene congener captured on the racemization pathway in its saddle-shaped geometry is introduced. Synthesis, structure, resolution, and dynamic properties of this chiral [6]saddlequat in-between highly stereocontrolled transformation into enantiopure [6]helquat are discussed demonstrated. The aspects established by experiment supported detailed DFT-D calculations presented visually form a movie (electronic table-of-contents electronic supplementary information). title was...
Most organic compounds provide vibrational spectra within the CH stretching region, yet signal is difficult to interpret because of multiple difficulties in experiment and modeling. To better understand various factors involved, ability several harmonic anharmonic computational approaches describe these vibrations was explored for α-pinene, fenchone, camphor as test compounds. Raman, Raman optical activity (ROA), infrared absorption (IR), circular dichroism (VCD) were measured compared...
The conformation of the milk protein alpha-lactalbumin has been studied using vibrational circular dichroism (VCD) and compared to parallel studies on lysozyme. These proteins have shown by Acharya et al. [(1989) J. Mol. Biol. 208, 99-127] very similar three-dimensional crystal structures. However, their VCD spectra in D2O solution are quite different. lysozyme more resembles that 33% propanol/D2O, under which conditions conformationally transformed a structure with increased helical...