The AlH3 adducts of TMEDA (Me2NCH2CH2NMe2), DIOX (O(CH2CH2)2O), TEA (Et3N), BDMA (PhNMe2), and TMPDA (Me2NCH2CH2CH2NMe2) have each been characterised by single-crystal X-ray diffraction at low temperature, by 1H, 14N and 27Al NMR and FT-Raman and FT-IR spectroscopy, and by DFT calculations and elemental analysis. Hence, AlH3·TMEDA and AlH3·DIOX are both shown to adopt a polymeric structure, with the bidentate ligand bridging two Al centres, each of which adopts a trigonal bipyramidal (TBP) arrangement with equatorial hydride moieties. The 1 : 2 adduct AlH3·2BDMA is monomeric but the geometry at the Al centre resembles closely that of the polymeric TMEDA and DIOX complexes. AlH3·TEA alone adopts a monomeric structure in which the Al centre is tetrahedrally coordinated by three hydride and one amine ligand. The Al–L bond distance of 2.0240(17) Å for AlH3·TEA is the shortest of all the complexes in this study, and AlH3·TEA also possesses the shortest Al–H bonds. AlH3·DIOX has the shortest Al–L bond distance of the polymeric species (2.107(14) Å) on account of the higher electronegativity of the oxygen donor. The structure of AlH3·TMEDA was determined at low temperature (monoclinic space group P21/c), and salient features are compared to the previous room temperature study, for which a highly disordered orthorhombic space group (P212121) was reported. The polymeric structures appear to be stabilised by a number of intermolecular interactions and unconventional hydrogen bonds; these are most pronounced for AlH3·DIOX, whose chains are connected by highly directional C–H⋯H–Al bonding with an H⋯H distance of 2.32(6) Å.
TME
DA(Me2NCH2CH2NMe2)、DIOX(O(CH2CH2)2O)、
TEA(Et3N)、
BDMA(PhNMe2)和
TMPDA(Me2NCH2CH2CH2NMe2)的
AlH3加合物均通过低温单晶X射线衍射、1H、14N和27Al核磁共振(NMR)、傅里叶变换拉曼(FT-Raman)和傅里叶变换红外(FT-IR)光谱、密度泛函理论(DFT)计算以及元素分析进行了表征。因此, ·TME
DA和 ·DIOX都显示出聚合物结构,其中双齿
配体桥接两个铝中心,每个铝中心均采用三角双锥(
TBP)排列,且有等热氢
配体。1:2加合物 ·2
BDMA是单体,但是铝中心的几何结构与聚合物TME
DA和DIOX复合物非常相似。 ·
TEA单独采用单体结构,其中铝中心被三个氢和一个胺
配体四面体配位。 ·
TEA的Al-L键长为2.0240(17) Å,是本研究中所有复合物中最短的, ·
TEA也具有最短的Al-H键。 ·DIOX的铝-L键长为2.107(14) Å,是聚合物中最短的,这是由于氧供体的电负性较高。 ·TME
DA的结构在低温下被确定(单斜空间群P21/c),其显著特征与之前的室温研究进行了比较,后者报告了一个高度无序的正交空间群(P212121)。聚合物结构似乎通过多种分子间相互作用和非常规氢键相互作用而得以稳定;这些特征在 ·DIOX中最为显著,其链通过高度定向的C–H⋯H–Al键相连,H⋯H的距离为2.32(6) Å。