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Spectroscopic and Theoretical Study of the Electronic Structure of Curcumin and Related Fragment Molecules
- Publication Year :
- 2008
-
Abstract
- The low volatility and thermal instability made the photoelectron (PE), electron transmission (ET), and dissociative electron attachment (DEA) spectroscopy measurements on curcumin (a potent chemopreventive agent) unsuccessful. The filled and empty electronic structure of curcumin was therefore investigated by exploiting the PES, ETS, and DEAS results for representative fragment molecules and suitable quantum-mechanical calculations. On this basis, a reliable pattern of the vertical ionization energies and electron attachment energies of curcumin was proposed. The π frontier molecular orbitals (MOs) are characterized by sizable interaction between the two phenol rings transmitted through the dicarbonyl chain and are associated with a remarkably low ionization energy and a negative electron attachment energy (i.e., a largely positive electron affinity), diagnostic of a stable anion state not observable in ETS. The lowest-energy electronic transitions of half-curcumin and curcumin and their color change by alkalization were interpreted with time-dependent density functional theory (DFT) calculations. For curcumin, it is shown that a loss of a phenolic proton occurs in alkaline ethanolic solution.
- Subjects :
- Curcumin
Chemistry
Stereochemistry
Spectrum Analysis
Anti-Inflammatory Agents, Non-Steroidal
ELECTRONIC STRUCTURE
Antineoplastic Agents
Electronic structure
Photochemistry
ABSORPTION SPECTRA
curcumin
photoelectron (PE)
electron transmission (ET)
dissociative electron attachment (DEA)
DFT
DISSOCIATIVE ELECTRON ATTACHMENT
Ion
Styrenes
Atomic electron transition
Molecule
Quantum Theory
AB INITIO AND DFT CALCULATIONS
Density functional theory
Molecular orbital
Physics::Chemical Physics
Physical and Theoretical Chemistry
Ionization energy
Spectroscopy
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....749d7a7ee6c5b4d25efe9768a0c26d55