Chemical Physics Letters, Vol.659, 55-60, 2016
UV fragmentation and ultrafast dynamics of trinuclear silver/1-methylthymine and silver/1-methyluracil metal-base pairs in an ion trap
We report on gas phase UV action spectroscopy and photodynamics of [Ag-3(1MT-H/1MU-H)(2)](+) comprised of a linear silver string and two deprotonated 1-methyl-thymine/uracil (1MT/1MU) ligands. We applied pump-probe femtosecond laser photofragmentation in an electrospray ion trap mass spectrometer and high-level ab initio calculations at the level of approximate coupled-cluster singles-doubles theory. The experimental UV band at 283/275 nm is assigned to a red shifted (1)pi pi* nucleobase located transition. Relaxation of the (1)pi pi* state occurs with time constants of 0.2/1.1 ps and 0.2/4.2 ps for the 1MT and 1MU complexes, respectively, on a similar ultrafast time scale as non-metalated uracil derivatives. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Metal-base pairs (MBP);Silver trimer;UV action spectroscopy;Time-resolved spectroscopy;Pump-probe photofragmentation;CC2