稀土杂多化合物在溶液中的^(183)W核磁共振表征

^(183)W NMR Characterization of Rare Earth Heterpolymetalates in Aqueous Solution

^（１８３）Ｗ核磁共振研究确认，Ｌａ（ＡｓＷ_（１１））_２、Ｌａｍ（Ａｓ_２Ｗ_（１７））_２在溶液中仍保持其四方反棱柱的Ｃ_３结构，Ｌａ（ＳｉＷ_９ＭＯ_２）_２阴离子中，２个Ｍｏ原子取代了２个等价的Ｗ原子，在穴状杂多阴离子ＬｎＡｓ_４Ｗ_（１０）和ＬｎＳｂ_９Ｗ_（２１）中，稀土离子占据中心Ｓ_１位置，ＳｉＷ_９与稀土离子生成（ＬｎＯ）_３（ＳｉＷ_９）_２型杂多阴离子。

?183)W NMR spectra were obtained for[La(AsW_(11)O(39))_2]￣(11-), [La(As_2W_(17)O_(61)_2 ]￣(17-),[La (SiW_9 Mo_2O_(39)_2 ]￣(13-) , [LaSb_9W_(21)O_(86)]￣(16-),[LaAs_4W_(40)O_(140)]￣(25-) and α-,β-[(CeO )_3·(SiW_9O_(34)_2]￣(14-) complexes.Tungsten NMR studies showed that the Cs symmetry of the square antiprism for[La AsW_(11)O_(39)_2]￣(11-) and[La(As2W_(17)O_(61)2]￣(17-)anions keep constant in aqueous solution; the lanthanide accupied the central S_1 site in[LnSb_9W_(21) O_(86)]￣(16-) and [LnAs_4W_(40)O_(140)]￣(25-) complexes,respectively,and lanthanide metal cations gave [(CeO)_3·(SiW_9O_(34))_2]￣(11-) type of complexes with SiW_9O_(34)￣(10-).