Copper(II) hexabromoplatinate (CuPtBr6) films have been prepared by mixing Cu2+ and PtBr62- ions in an aqueous KBr solution. An electrochemical quartz crystal microbalance (EQCM), a rotating ring-disk electrode, UV-visible absorption spectroscopy and cyclic voltammetry were used to study the deposition and growth mechanism of the copper(II) hexabromoplatinate films. The electrochemical and EQCM properties of the films indicate that a single redox process was confined to the immobilized copper(II) hexabromoplatinate films. The deposition of a copper hexabromoplatinate film occurs when Cu2+ is reduced to Cu+. In the aqueous KBr solution, (PtBr62-)-Br-IV is reduced electrochemically to (PtBr64-)-Br-II, and the Cu+ reacts with the (PtBr64-)-Br-II and (PtBr62-)-Br-IV species. The electrocatalytic oxidation properties of dopamine, NADH, and S2O32- were determined using the copper(II) hexabromoplatinate films. The electrocatalytic reaction of dopamine with a copper(II) hexabromoplatinate film was investigated using the rotating ring-disk electrode method. (C) 2004 Elsevier B.V. All rights reserved.