화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.109, No.27, 13083-13090, 2005
Structure and spectroscopy of Tb[Au(CN)(2)](3)center dot 3H(2)O
The compound Tb[Au(CN)(2)](3)center dot 3H(2)O crystallizes in a layered structure in the hexagonal space group P6(3)/MCM with the 9-coordinate environment of Tb3+ Comprising six (CN)(-) and three OH2 in a tricapped trigonal prism. The shortest (AuAu)-Au-... distance is 3.31 angstrom. The vibrational spectra show that the series Ln[Au(CN)(2)](3)-3H(2)O (Ln = Y, Pr, Sm, Eu, Tb) are isostructural. The electronic spectra of Eu[Au(CN)(2)](3)center dot 3H(2)O clearly show that Eu3+ occupies one site of spectroscopic site symmetry D-3h, in agreement with the crystallographic data. The electronic emission and absorption spectra of Tb[Au(CN)(2)](3)center dot 3H(2)O have been recorded at temperatures down to 1.5 K, and the f-f pure electronic transitions are interpreted in detail as arising from the lowest electronic states (in D-3h symmetry) (F-7(6))E' in absorption and (D-5(4))E" in emission. At low energy, further bands are assigned to the vibronic structure of the C equivalent to N stretching and water stretching modes, with the latter more predominant. Although the C equivalent to N stretching vibrations show exclusive infrared or Raman activity in Tb[Au(CN)(2)](3)center dot 3H(2)O, both of these infrared and Raman active modes are observed in the two-center vibronic transitions. The reasons for this are discussed.