Syntheses and Structures of [(THF)<i><sub>n</sub></i>M{(NSiMe<sub>3</sub>)<sub>2</sub>PPh<sub>2</sub>}<sub>2</sub>] Complexes (M = Be, Mg, Ca, Sr, Ba; <i>n</i> = 0−2): Deviation of Alkaline Earth Metal Cations from the Plane of an Anionic Ligand
作者:Roland Fleischer、Dietmar Stalke
DOI:10.1021/ic9613117
日期:1997.5.1
The syntheses and solid-state structures of [(THF)(n)()M(NSiMe(3))(2)PPh(2)}(2)] (M = Be, n = 0, 1; M = Mg, n = 0, 2; M = Ca, n = 1, 3; M = Sr, n = 2, 4; M = Ba, n = 2, 5) are presented. Comparison of the geometric parameters within the homologous series and to related systems uncovers the dication-induced alterations of coordination to, as well as bonding within, the anionic fragment. The coordination
[(THF)(n)()M (NSiMe(3))(2)PPh(2)}(2)的合成和固态结构(M = Be,n = 0,1; M = Mg,n = 0,2; M = Ca,n = 1、3; M = Sr,n = 2,4; M = Ba,n = 2,5)。同源序列和相关系统中几何参数的比较揭示了阳离子诱导的阴离子片段配位以及键合的改变。配位数从4(Be,Mg)通过5(Ca)增加到6(Sr,Ba)。Ph(2)P(Me(3)SiN)(2)阴离子中的两个覆盖了铍和镁的配位域,而钙仅含一个THF分子,锶和钡仅含两个额外的THF分子才能完成金属协调领域。出于空间考虑,在4和5中的两个THF分子与金属的同一半球配位,而留下两个阴离子的类固醇。即使对抗空间应变,碱土金属也会随着质量的增加而离开Ph(2)P(Me(3)SiN)(2)阴离子之一的平面,这表明Sr和Ba与pi电子密度相互作用的偏好。在相关系统中也