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Doorley, Gerard W.
Preferred name
Doorley, Gerard W.
Official Name
Doorley, Gerard W.
Research Output
Now showing 1 - 4 of 4
- PublicationTracking DNA excited states by picosecond-time-resolved infrared spectroscopy: Signature band for a charge-transfer excited state in stacked adenine-thymine systems(American Chemical Society, 2013-07-29)
; ; ; ; UV photoexcitation of an adenine-thymine heterodimer (ApT) in D 2O yields a complex transient infrared signature in the 1500-1600 cm-1 spectral region. The spectral dynamics fit well to a biexponential decay assignable to two transient species. The first, a short-lived species with a lifetime of ca. 5 ps, originates from the vibrationally hot electronic ground state of the unstacked form of the dinucleotide. The second species is longer-lived (ca. 75 ps), and its yield correlates to the amount of stacked dinucleotide present in solution. We assign the longer-lived component to a charge-transfer (A•+pT •-) state by comparison with calculated spectra for the adenine radical cation and thymine radical anion. Significantly, the CT feature is also identified in UV-excited [poly(dA-dT)]2. This experimental observation gives a powerful insight into how base-base interactions lead to extended-lifetime electronic excited states of the nucleic acid bases and how a dimeric structure controls the relaxation pathway. © 2013 American Chemical Society.161Scopus© Citations 68 - PublicationLong-lived excited states in i-motif DNA studied by picosecond time-resolved IR spectroscopy(Royal Society of Chemistry, 2014-03-21)
; ; ; ; ; The transient IR absorption spectrum for UV-excited i-motif DNA is reported for the first time and found to possess complex dynamics pointing to multiple decay processes, including possible charge transfer between packed hemi-protonated C bases.182Scopus© Citations 22 - PublicationA comparative picosecond transient infrared study of 1-methylcytosine and 5'-dCMP that sheds further light on the excited states of cytosine derivatives(ACS Publications, 2011-03)
; ; ; ; ; ; ; ; ; The role of N1-substitution in controlling the deactivation processes in photoexcited cytosine derivatives has been explored using picosecond time-resolved IR spectroscopy. The simplest N1-substituted derivative, 1-methylcytosine, exhibits relaxation dynamics similar to the cytosine nucleobase and distinct from the biologically relevant nucleotide and nucleoside analogues, which have longer-lived excited-state intermediates. It is suggested that this is the case because the sugar group either facilitates access to the long-lived (1)n(O)Ï * state or retards its crossover to the ground state.413Scopus© Citations 40 - PublicationUltrafast IR spectroscopy of polymeric cytosine nucleic acids reveal the long-lived species is due to a localised state(RSC Publishing, 2012-02-22)
; ; ; ; ; ; ; ; ; The decay pathways of UV-excited cytosine polymers are investigated using picosecond time-resolved infrared spectroscopy. Similar yields of a non-emissive (1)nÏ * state are found in the single-stranded dC(30) polymer as in the dCMP monomer, but with a longer lifetime in the polymer (80 ps vs. 39 ps). A longer lifetime is also found in the d(CpC) dinucleotide. No evidence of excimer states is observed, suggesting that localised (1)nÏ * excited states are the most significant intermediates present on the picosecond timescale.332Scopus© Citations 10