Six- and eight-coordinate thio- and seleno-ether complexes of NbF<sub>5</sub>and some comparisons with NbCl5 and NbBr5 adducts
作者:Marek Jura、William Levason、Raju Ratnani、Gillian Reid、Michael Webster
DOI:10.1039/b916336k
日期:——
The reaction of RS(CH2)2SR (R = Me, Et or iPr) with NbF5 produces [NbF4RS(CH2)2SR}2][NbF6] which contain distorted eight-coordinate (dodecahedral) cations and octahedral anions, whereas RSe(CH2)2SeR (R = Me or Bun) form six-coordinate [(NbF5)2(μ-RSe(CH2)2SeR)]. Et2S and Me2Se (L) also form six-coordinate [NbF5(L)], but Me2S forms both [NbF5(Me2S)] and an eight-coordinate cation in [NbF4(Me2S)4][NbF6]. MeS(CH2)2SMe forms eight-coordinate cations in [NbX4MeS(CH2)2SMe}2][NbX6] (X = Cl or Br), but other complexes of the heavier halides including [NbX5(L)] and [(NbX5)2(μ-L–L)] (L–L = RSe(CH2)2SeR; o-C6H4(CH2SMe)2 and o-C6H4(CH2SeMe)2) contain six-coordinate niobium. The very unstable [NbCl5(Me2Te)] was characterised spectroscopically, but all other attempts to form telluroether complexes resulted in decomposition, and NbI5 was reduced even by thioethers. The complexes have been characterised by multinuclear NMR (1H, 19F, 93Nb, 77Se or 125Te), IR and UV/visible spectroscopy, and X-ray crystal structures are reported for [NbF4RS(CH2)2SR}2][NbF6] (R = Me, iPr), [NbF4(Me2S)4][NbF6], [NbCl5(Me2Se)], [NbBr5(Me2S)], [(NbCl5)2o-C6H4(CH2SMe)2}] and [(NbCl5)2MeSe(CH2)2SeMe}]. All the complexes are very moisture sensitive and the fluoride complexes decompose slowly with fluorination of the neutral ligand.
RS(CH2)2SR(R = Me、Et 或 iPr)与 NbF5 反应生成 [NbF4RS(CH2)2SR}2][NbF6],其中含有畸变的八配位(十二面体)阳离子和八面体阴离子,而 RSe(CH2)2SeR(R = Me 或 Bun)则形成六配位的 [(NbF5)2(μ-RSe(CH2)2SeR)]。Et2S 和 Me2Se(L)也会形成六配位的 [NbF5(L)],但 Me2S 既会形成 [NbF5(Me2S)],也会在 [NbF4(Me2S)4][NbF6] 中形成八配位阳离子。MeS(CH2)2SMe在[NbX4MeS(CH2)2SMe}2][NbX6](X = Cl 或 Br)中形成八配位阳离子,但包括[NbX5(L)]和[(NbX5)2(μ-L-L)](L-L = RSe(CH2)2SeR;o-C6H4(CH2SMe)2 和 o-C6H4(CH2SeMe)2)在内的其他较重卤化物配合物则含有六配位铌。对非常不稳定的 [NbCl5(Me2Te)]进行了光谱表征,但所有其他试图形成碲醚配合物的尝试都导致了分解,NbI5 甚至被硫醚还原。这些复合物通过多核核磁共振(1H、19F、93Nb、77Se 或 125Te)、红外光谱和紫外/可见光谱进行了表征、并报告了 [NbF4RS(CH2)2SR}2][NbF6] (R = Me、iPr)、[NbF4(Me2S)4][NbF6]、[NbCl5(Me2Se)]、[NbBr5(Me2S)]、[(NbCl5)2o-C6H4(CH2SMe)2}] 和 [(NbCl5)2MeSe(CH2)2SeMe}] 的 X 射线晶体结构。所有配合物对湿度都非常敏感,氟化物配合物在中性配体氟化后分解缓慢。