Cryogenic IR and UV spectroscopy of isomer-selected cytosine radical cation.
Franco MolinaJordan DezalaySatchin SoorkiaMichel BroquierMajdi HochlafGustavo Ariel PinoGilles GrégoirePublished in: Physical chemistry chemical physics : PCCP (2022)
Oxidation of the nucleobases is of great concern for the stability of DNA strands and is considered as a source of mutagenesis and cancer. However, precise spectroscopy data, in particular in their electronic excited states are scarce if not missing. We here report an original way to produce isomer-selected radical cations of DNA bases, exemplified in the case of cytosine, through the photodissociation of cold cytosine-silver (C-Ag + ) complex. IR-UV dip spectroscopy of C-Ag + features fingerprint bands for the two keto-amino cytosine tautomers. UV photodissociation (UVPD) of the isomer-selected C-Ag + complexes produces the cytosine radical cation (C˙ + ) without isomerization. IR-UV cryogenic ion spectroscopy of C˙ + allows for the unambiguous structural assignment of the two keto-amino isomers of C˙ + . UVPD spectroscopy of the isomer-selected C˙ + species is recorded at a unique spectral resolution. These benchmark spectroscopic data of the electronic excited states of C˙ + are used to assess the quantum chemistry calculations performed at the TD-DFT, CASSCF/CASPT2 and CASSCF/MRCI-F12 levels.
Keyphrases
- single molecule
- high resolution
- solid state
- quantum dots
- ionic liquid
- molecular dynamics
- molecular docking
- density functional theory
- electronic health record
- big data
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- aqueous solution
- energy transfer
- highly efficient
- computed tomography
- gold nanoparticles
- nitric oxide
- molecular dynamics simulations
- nucleic acid
- deep learning
- squamous cell
- crystal structure
- data analysis