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Updated: Mar 25, 2026

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Long-Lived Excited-State Dynamics of i-Motif Structures Probed by Time-Resolved Infrared Spectroscopy
Páraic M Keane1, Frederico R Baptista2, Sarah P Gurung3,4
1Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK. p.keane@reading.ac.uk.
Abstract:
UV-generated excited states of cytosine (C) nucleobases are precursors to mutagenic photoproduct formation. The i-motif formed from C-rich sequences is known to exhibit high yields of long-lived excited states following UV absorption. Here the excited states of several i-motif structures have been characterized following 267 nm laser excitation using time-resolved infrared spectroscopy (TRIR). All structures possess a long-lived excited state of ∼300 ps and notably in some cases decays greater than 1 ns are observed. These unusually long-lived lifetimes are attributed to the interdigitated DNA structure which prevents direct base stacking overlap.
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