Knowledge Bank

Tropolone (TrOH) serves as a model system for the study of coherent proton-transfer processes, where a potential barrier of finite height hinders the symmetric exchange of a lone hydron between hydroxylic (proton-donating) and ketonic (proton-accepting) oxygen centers. This talk will discuss ongoing efforts to build upon the known structural and dynamical properties of tropolone so as to explore related multiple proton-transfer events that are mediated by successive formation and breaking of several hydrogen bonds. Of particular interest are weakly-bound complexes created \emph{in situ} under "cold'' molecular-beam conditions by docking amphoteric ligands (\emph{e.g.}, HF and HCOOH) into the reaction cleft of the TrOH substrate. Such species have the tantalizing possibility of undergoing double proton transfer,, $108$, 1171 (2010).} with resulting tunneling-induced bifurcation of rovibronic features reflecting the intrinsic vibrational and/or electronic specificity of the attendant unimolecular transformation. Spectroscopic studies of several hydrogen-bound TrOH complexes through use of the richly structured $\tilde{A}^{1}\rm{B}{2}-\tilde{X}^{1}\rm{A}{1} (\pi ^{*}\leftarrow \pi $) absorption system will be presented, with complementary quantum-chemical calculations serving to guide the assignment and interpretation of observed spectral patterns.