title: Syntheses, crystal structures, magnetic and luminescent properties of two classes of molybdenum(VI) rich quaternary lanthanide selenites.
abstract: Hydrothermal reactions of lanthanide(III) oxide, molybdenum oxide, and SeO(2) at 230 °C lead to five new molybdenum-rich quaternary lanthanide selenites with two types of structures, namely, H(3)Ln(4)Mo(9.5)O(32)(SeO(3))(4)(H(2)O)(2) (Ln = La, 1; Nd, 2) and Ln(2)Mo(3)O(10)(SeO(3))(2)(H(2)O) (Ln = Eu, 3; Dy, 4; Er, 5). Compounds 1 and 2 feature a complicated three-dimensional (3D) architecture constructed by the intergrowth of infinite molybdenum selenite chains of [Mo(4.75)SeO(19)](5.5-) and one-dimensional (1D) lanthanide selenite chains. The structures of 3, 4, and 5 exhibit 3D network composed of 1D [Mo(3)SeO(13)](4-) anionic chains connected by lanthanide selenite chains. The molybdenum selenite chain of [Mo(4.75)SeO(19)](5.5-) in 1 and 2 is composed of a pair of [Mo(3)SeO(13)](4-) chains as in 3, 4, and 5 interconnected by a [Mo(1.75)O(8)](5.5-) double-strand polymer via corner-sharing. The lanthanide selenite chains in both structures are similar in terms of coordination modes of selenite groups as well as the coordination environments of lanthanide(III) ions. Luminescent studies at both room temperature and 10 K indicate that compound 2 displays strong luminescence in the near-IR region and compound 3 exhibits red fluorescent emission bands with a luminescent lifetime of 0.57 ms. Magnetic properties of these compounds have been also investigated.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, PR China.
authors.forename: Su-Yun
authors.initials: SY
authors.lastname: Zhang
authors.forename: Jiang-Gao
authors.initials: JG
authors.lastname: Mao