CH3CN solution

It has been known for a long time that the reaction of Cu(I) with halogenide ions leads to halogenocuprates(I)- compounds which contain anions of the type [Cu x Iy](y-x)- [1]. Although iodine-containing copper compounds in solution are used as oxygen transmitters in catalysis [2], there are only few information (vibrational spectra[3]) on the composition of iodocuprates(I) in solvents. As described elsewhere [4,5], various amounts of three selected iodocuprates(I) R2[Cu2I4], R’2[Cu5I7] and R’2[Cu5I7(CH3CN)2] (R, R ’ = organic cation) with differing anionic partial structure were dissolved in acetonitrile (CH3CN) and XAFS measurements were performed. The CuK-XANES-spectra of these three compounds displayed with rising concentration of the iodocuprate anions in solution increasing delocalisation of the p-orbitals and a shift to higher EXAFS frequencies which corresponds to a formation of larger clusters and a lengthening of the Cu-I distances, respectively. Contrary to the congruent spectra of the solutions, the CuK-XANES-spectra of these three compounds in their solid state differ very much. CuK-XANES-measurements of CuI/I--mixtures in acetonitrile and a comparison of these XANES