Alkali metal complexes of a phosphine–borane-stabilised carbanion: influence of co-ligands on structure
作者:Keith Izod、Corinne Wills、William Clegg、Ross W. Harrington
DOI:10.1039/b708279g
日期:——
The adducts [[(Me3Si)2Me2P(BH3)}C]K(L)n]m [L = THF, n = 0.5, m = â (2a); L = tmeda (2b), pmdeta (2c), n = 1, m = 2] may be synthesised by treatment of solvent-free [[(Me3Si)2Me2P(BH3)}C]K]â (2) with the corresponding Lewis base (tmeda = N,N,Nâ²,Nâ²-tetramethylethylenediamine; pmdeta = N,N,Nâ²,Nâ³,Nâ³-pentamethyldiethylenetriamine). X-Ray crystallography reveals that, whereas 2 crystallises with a complex 2-dimensional sheet structure, 2a crystallises as a ribbon-type one-dimensional polymer and both 2b and 2c crystallise as dimers. The corresponding complex with 12-crown-4, [K(12-crown-4)2][(Me3Si)2Me2P(BH3)}C] (2d) crystallises as a separated ion pair. The complexes [[(Me3Si)2Me2P(BH3)}C]M(pmdeta)]n [M = Na, n = 1 (6); M = Rb, n = 2 (7)] may be synthesised by treatment of [(Me3Si)2Me2P(BH3)}C]M with pmdeta. Whereas 6 crystallises as a discrete monomer, compound 7 crystallises as a dimer. Compounds 2, 2aâ2d, 6, 7 and the corresponding caesium derivative [[(Me3Si)2Me2P(BH3)}C]Cs(pmdeta)]2 (5) provide an opportunity to consider the influence of the ionic radius of the metal and the nature of the co-ligands on the structures of alkali metal complexes of a phosphineâborane-stabilised carbanion.
加合物[[(Me3Si)2Me2P(BH3)}C]K(L)n]m [L = THF,n = 0.5,m = â (2a);L = tmeda (2b),pmdeta (2c),n = 1,m = 2]可以通过用相应的路易斯碱(tmeda = N,N,Nâ²,Nâ²-四甲基乙二胺,pmdeta = N,N,Nâ²-四甲基乙二胺)处理无溶剂的[[(Me3Si)2Me2P(BH3)}C]K]â (2)来合成;pmdeta = N,N,Nâ²,Nâ³,Nâ³-五甲基二乙烯三胺)。X 射线晶体学显示,2 结晶为复杂的二维片状结构,2a 结晶为带状一维聚合物,2b 和 2c 结晶为二聚体。与 12-冠-4([K(12-冠-4)2][(Me3Si)2Me2P(BH3)}C](2d)相应的配合物以分离的离子对形式结晶。通过用 pmdeta 处理[(Me3Si)2Me2P(BH3)}C]M(pmdeta)]n [M = Na,n = 1 (6);M = Rb,n = 2 (7)],可以合成[[(Me3Si)2Me2P(BH3)}C]M(pmdeta)]n 复合物。6 以离散的单体形式结晶,而化合物 7 则以二聚体形式结晶。化合物 2、2aâ2d、6、7 和相应的铯衍生物 [[(Me3Si)2Me2P(BH3)}C]Cs(pmdeta)]2(5)提供了一个机会,让我们来考虑金属的离子半径和共配位体的性质对膦硼烷稳定的碳阴离子碱金属配合物结构的影响。