Synthesis, Structures, and Properties of a Series of [Cd8Se(SePh)12Cl4]2− Cluster Compounds with Different Counterions

Abstract

AbstractA series of seven single‐crystalline ionic CdSe cluster compounds, all possessing the cluster anion [Cd8Se(SePh)12Cl4]2−, but with different counterions, has been synthesized. The compounds were characterized in the solid state, solution, and gas phases using single‐crystal XRD, powder XRD, UV/Vis spectroscopy, and FT mass spectrometry. The results of the crystal structure determination show that the increasing size of the different counterions does not simply lead to an increase in the shortest inter‐cluster distance, but rather to changes in the crystal structure. Room‐temperature UV/Vis absorption and reflectance spectra of the crystalline powders are virtually identical, proving that the electronic transitions in the energy range probed can be attributed to the cluster anion [Cd8Se(SePh)12Cl4]2−. The band of the first transition in the solid‐state UV/Vis spectra are broadened relative to that in the solution spectra, as it is possibly affected by the collective interactions between the nanoclusters in the three‐dimensional crystal lattice. Interestingly, in solution, the position and feature of the lowest‐energy transition band changes as the solvent is varied. As FT mass spectrometry gives clear evidence for the existence of the intact [Cd8Se(SePh)12Cl4]2− cluster anion in all these solutions, these shifts can be interpreted in terms of solvatochromic effects. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)