[Y(IO3)3(H2O)2]n: a New Rare Earth Iodate Featuring the Circle-shaped I4O12 Polyiodate Anion and Three-order Nonlinear Optical Property

A new layered yttrium iodate [Y(IO3)(3)(H2O)(2)](n) (1) has been prepared from the hydrothermal reaction of Y(NO3)(3)center dot 6H(2)O with I2O5 at 170 degrees C, and its structure was determined by X-ray single-crystal diffraction method. It belongs to the triclinic system, space group P (1) over bar with a = 7.355(5), b = 7.515(5), c = 9.413(7) angstrom, alpha = 79.65(2)degrees, beta = 85.18(3)degrees, gamma = 71.870(19)degrees, Z = 2, V = 486.2(6) angstrom(3). 1 was further characterized by FTIR, powder X-ray diffraction (PXRD) and UV-Vis spectra. In 1, the Y centers in a monocapped trigonal prism environment are bound by IO3- anion and unique circle-shaped I4O12 polyiodate anion to generate a wave-like 2-D layer. The adjacent layers are further linked with each other by hydrogen bonds to form a quasi-3-D supramolecular network. 1 exhibits a reverse saturation absorption and a self-defocusing effect with the nonlinear absorption coefficient beta being -0.66 x 10(-5) mW(-1), which stems mainly from the electron transition from O-2p to I-5p orbital within iodates upon theoretical calculation.