Detailed structural understanding of ultrafast electron transfer processes would lead to high level of control over charge flow in molecular devices. To unravel this structural dependence, we investigate whether electron transfer rates in nonadiabatically coupled p-conjugated systems can be controlled by a few non-local vibrational modes. We consider a model comprising an anthraquinone dye solvated in electron donating solvents (aniline and its derivatives) which are known to quench the long-lived excited states. Our time-resolved emission studies revealed that charge transfer occurs in the subpicosecond regime (~300-700 fs), much faster than the solvent relaxation timescales. The resonance Raman measurements within the local S1band of the solvated dye, showed enhanced in-plane ring breathing and out-of-plane ring deformation modes. Theoretical modelling of the dye-solvent interactions gave us invaluable insights into the correlation of these two modes with the propensity of electron transfer. Through this work, we will discuss the importance of global motions in rationally tailoring efficient through-space charge transfer.

Fluorescence quenching in solvated anthraquinones: Significance of low-frequency vibrations

245th National Meeting (2013)

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