An insight into the disorder properties of the -cyclodextrin polyiodide inclusion complex with Sr2+ion: dielectric, DSC and FT-Raman spectroscopy studies

作者：Charalampopoulos V G^*; Papaioannou J C; Viras K; Karayianni H S; Kakali G

来源：Supramolecular Chemistry, 2010, 22(9): 499-510.

DOI：10.1080/10610278.2010.487563

• cyclodextrin inclusion complexes
• dielectric relaxation
• disorder phenomena
• pentaiodide transformations
• Raman scattering

At T250K, the polyiodide inclusion complex (-cyclodextrin)2 center dot Sr0.5 center dot I5 center dot 17H2O displays two separate relaxation processes due to both the frozen-in proton motions in an otherwise ordered H-bonding network and the order-disorder transition of some normal H-bonds to flip-flop ones. At T250K, the AC-conductivity is dominated by the combinational contributions of the disordered water network, the mobile Sr2+ ions, the polyiodide charge-transfer interactions and the dehydration process. The evolution of the Raman spectroscopic data with temperature reveals the coexistence of four discrete pentaiodide forms. In form (I) (I-3 center dot I2I2 center dot I-3), the occupancy ratio (x/y) of the central I- ion differs from 50/50. In form (IIa) (I2 center dot I-center dot I2) x/y=50/50, whereas in its equivalent form (IIb) (I2 center dot I-center dot I2)* as well as in form (III) (I-3 center dot I2), x/y=100/0 (indicative of full occupancy). Through slow cooling and heating, the inverse transformations (I)(IIa) and (IIa)(I) occur, respectively. [image omitted].

• 出版日期2010