Persistence of a Delocalized Radical in Larger Clusters of Hydrated Copper(II) Hydroxide, CuOH + (H 2 O) 3-7 .

The structures, vibrational spectra, and electronic properties of copper hydroxide hydrates CuOH + (H 2 O) 3-7 were investigated with quantum chemistry computations. As a follow-up to a previous analysis of CuOH + (H 2 O) 0-2 , this investigation examined the progression as the square-planar metal coordination environment was filled and as solvation shells expanded. Four-, five-, and six-coordinate structures were found to be low-energy isomers. The delocalized radical character, which was discovered in the small clusters, was found to persist upon continued hydration, although the hydrogen-bonded water network in the larger clusters was found to play a more significant role in accommodating this spin. Partial charges indicated that the electronic structure includes more Cu 2+ ···OH - character than was observed in smaller clusters, but this structure remains decidedly mixed with Cu + ···OH · configurations and yields roughly half-oxidation of the water network in the absence of any electrochemical potential. Computed vibrational spectra for n = 3 showed congruence with spectra from recent predissociation spectroscopy experiments, provided that the role of the D 2 tag was taken into account. Spectra for n = 4-7 were predicted to exhibit features that are reflective of both the mixed electronic character and proton-/hydrogen-shuttling motifs within the hydrogen-bonded water network.