A simple dimeric model accounts for the vibronic ECD spectra of chiral polythiophenes in their aggregated states

RSC Advances ◽  
2016 ◽  
Vol 6 (44) ◽  
pp. 37938-37943 ◽  
Author(s):  
Daniele Padula ◽  
Fabrizio Santoro ◽  
Gennaro Pescitelli
Keyword(s):  
Circular Dichroism ◽  
Electronic Circular Dichroism ◽  
Vibronic Structure ◽  
Quantum Dynamical ◽  
Dynamical Simulations ◽  
Circular Dichroïsm ◽  
Dimeric Model

Aggregates of chiral polythiophenes (PTs) show exciton-coupled electronic circular dichroism (ECD) spectra with a unique vibronic structure, which can be reproduced by quantum dynamical simulations on the coupled states of small dimeric models.

Vibronic structure in the far-UV electronic circular dichroism spectra of proteins

2015 ◽  
Vol 177 ◽  
pp. 329-344 ◽  
Author(s):  
Zhuo Li ◽  
David Robinson ◽  
Jonathan D. Hirst
Keyword(s):  
Circular Dichroism ◽  
Matrix Method ◽  
Vibrational Structure ◽  
Cd Spectra ◽  
Peptide Backbone ◽  
Electronic Circular Dichroism ◽  
Vibronic Structure ◽  
Far Ultraviolet ◽  
High Level ◽  
Circular Dichroïsm

The Franck–Condon effect is considered and the vibrational structure of the πnbπ* transition of the peptide backbone is incorporated into matrix method calculations of the electronic circular dichroism (CD) spectra of proteins in the far-ultraviolet. We employ the state-averaged CASPT2 method to calculate the ground and πnbπ* excited state geometries and frequencies of N-methylacetamide (NMA), which represents the peptide chromophore. The results of these calculations are used to incorporate vibronic levels of the excited states into the matrix method calculation. The CD spectra of a set of 49 proteins, comprising a range of structural types, are calculated to assess the influence of the vibrational structure. The calculated spectra of α-helical proteins are better resolved using the vibronic parameters and correlation between the experimental and the calculated intensity of less regular β structure proteins improves over most wavelengths in the far-UV. No obvious improvement is observed in the calculated spectra of regular β-sheet proteins. Our high-level ab initio calculations of the vibronic structure of the πnbπ* transition in NMA have provided some further insight into the physical origins of the nature of protein CD spectra in the far-UV.

Electronic Circular Dichroism in Exciton-Coupled Dimers: Vibronic Spectra from a General All-Coordinates Quantum-Dynamical Approach

2013 ◽  
Vol 117 (16) ◽  
pp. 3355-3368 ◽  
Author(s):  
Daniele Padula ◽  
David Picconi ◽  
Alessandro Lami ◽  
Gennaro Pescitelli ◽  
Fabrizio Santoro
Keyword(s):  
Circular Dichroism ◽  
Electronic Circular Dichroism ◽  
Quantum Dynamical ◽  
Dynamical Approach ◽  
Vibronic Spectra ◽  
Circular Dichroïsm

scholarly journals Mass-resolved electronic circular dichroism ion spectroscopy

Science ◽  
2020 ◽  
Vol 368 (6498) ◽  
pp. 1465-1468 ◽  
Author(s):  
Steven Daly ◽  
Frédéric Rosu ◽  
Valérie Gabelica
Keyword(s):  
Circular Dichroism ◽  
Three Dimensional ◽  
Polarized Light ◽  
Negative Ions ◽  
Data Interpretation ◽  
Electronic Circular Dichroism ◽  
Circularly Polarized Light ◽  
Chiral Compounds ◽  
Electron Photodetachment ◽  
Circular Dichroïsm

DNA and proteins are chiral: Their three-dimensional structures cannot be superimposed with their mirror images. Circular dichroism spectroscopy is widely used to characterize chiral compounds, but data interpretation is difficult in the case of mixtures. We recorded the electronic circular dichroism spectra of DNA helices separated in a mass spectrometer. We studied guanine-rich strands having various secondary structures, electrosprayed them as negative ions, irradiated them with an ultraviolet nanosecond optical parametric oscillator laser, and measured the difference in electron photodetachment efficiency between left and right circularly polarized light. The reconstructed circular dichroism ion spectra resembled those of their solution-phase counterparts, thereby allowing us to assign the DNA helical topology. The ability to measure circular dichroism directly on biomolecular ions expands the capabilities of mass spectrometry for structural analysis.

Chemical Constituents from Chloranthus elatior and Their Inhibitory Effect on Human Dihydroorotate Dehydrogenase

Planta Medica ◽  
2021 ◽  
Author(s):  
Qian Yang ◽  
An Jia ◽  
Xizi Liu ◽  
Shiyi Han ◽  
Siyang Fan
Keyword(s):  
Circular Dichroism ◽  
Chemical Constituents ◽  
Inhibitory Effect ◽  
Mass Spectrometric ◽  
Dihydroorotate Dehydrogenase ◽  
Active Compounds ◽  
Electronic Circular Dichroism ◽  
Aerial Parts ◽  
Ic50 Values ◽  
Circular Dichroïsm

AbstractA new sesquiterpene, chlorantholide G (1), a new sesquiterpene dimer, elatiolactone (2), and 2 new diterpenes, elatiorlabdane B (3) and elatiorlabdane C (4), together with 51 known compounds, were isolated from the aerial parts of Chloranthus elatior. The new structures including their absolute configurations were mainly established by mass spectrometric, NMR, and electronic circular dichroism experiments. All isolated compounds were tested for their anti-hDHODH activity. (4S,6R)-4-hydroxy-6-isopropyl-3-methylcyclohex-2-enone (5) and (4S,5R,9S,10R)-8(17),12,14-labdatrien-18-oic acid (29) were the most active compounds with IC50 values of 18.7 and 30.7 µM, respectively.

Enantiopure methoxetamine stereoisomers: chiral resolution, conformational analysis, UV-circular dichroism spectroscopy and electronic circular dichroism

2021 ◽  
Author(s):  
Kun Won Lee ◽  
Ahmed H. E. Hassan ◽  
Youngdo Jeong ◽  
Seolmin Yoon ◽  
Seung-Hwan Kim ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Conformational Analysis ◽  
Absolute Configuration ◽  
Circular Dichroism Spectroscopy ◽  
Chiral Resolution ◽  
Treatment Resistant Depression ◽  
Treatment Resistant ◽  
Electronic Circular Dichroism ◽  
Resistant Depression ◽  
Circular Dichroïsm

Enantioseparation and assignment of absolute configuration of methoxetamine (MXE) enantiopure stereoisomers; a promising novel antidepressant for management of treatment-resistant depression.

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