Infrared photodissociation spectra and solvation structures of Cu+(H2O)n (n = 1–4)

Coordination and solvation structures of the Cu+(H2O)n ions with n = 1–4 are studied by infrared photodissociation spectroscopy and density functional theory calculations. Hydrogen-bonding between H2O molecules is detected in Cu+(H2O)3 and Cu+(H2O)4 through a characteristic change in the position and intensity of OH-stretching transitions. The third and fourth waters prefer hydrogen-bonding sites in the second solvation shell rather than direct coordination to Cu+. The infrared spectroscopy verifies that the gas-phase coordination number of Cu+ in Cu+(H2O)n is two and the resulting linearly coordinated structure acts as the core of further solvation processes.