Metal–heptaiodide interactions in cyclomaltoheptaose (β-cyclodextrin) polyiodide complexes as detected via Raman spectroscopy Original Research Article

The Raman spectra of the cyclomaltoheptaose (β-cyclodextrin, β-CD) polyiodide complexes (β-CD)2·NaI7·12H2O, (β-CD)2·RbI7·18H2O, (β-CD)2·SrI7·17H2O, (β-CD)2·BiI7·17H2O and (β-CD)2·VI7·14H2O (named β-M, M stands for the corresponding metal) are investigated in the temperature range of 30–140 °C. At room temperature all systems show an initial strong band at 178 cm−1 that reveals similar intramolecular distances of the disordered I2 units (∼2.72 Å). During the heating process β-Na and β-Rb display a gradual shift of this band to the final single frequency of 166 cm−1. In the case of β-Sr and β-Bi, the band at 178 c