Chen Jiawei, Chen Eugene Y-X
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA.
Dalton Trans. 2016 Apr 14;45(14):6105-10. doi: 10.1039/c5dt03895b. Epub 2015 Nov 16.
Alkyl/aryl ligand exchange between AlEt3 and B(C6F5)3 in hexanes enables the formation and isolation of the unsolvated Al(C6F5)3 as a crystalline solid, the structure of which has been determined by single-crystal X-ray diffraction analysis. Instead of forming the anticipated AlF contacts with the seemingly more accessible meta- and para-F's of -C6F5 groups, two Al(C6F5)3 molecules form a dimeric structure with double AlF interactions between the Al center of one molecule and the ortho-F atom of the -C6F5 group on the other molecule. This mode of interactions is apparently linked to the thermal and shock sensitivity of the unsolvated Al(C6F5)3 in the solid state. To compare with the B(C6F5)3/ferrocene frustrated Lewis pair system, the complexation between Al(C6F5)3 and ferrocene has also been studied, which affords a stable adduct formed through the η(1)-coordination of Al to one of the CCp atoms, similar to the alane-toluene or benzene complex.
在己烷中，三乙基铝（AlEt₃）与三（五氟苯基）硼（B(C₆F₅)₃）之间发生烷基/芳基配体交换，能够形成并分离出未溶剂化的三（五氟苯基）铝（Al(C₆F₅)₃）晶体，其结构已通过单晶X射线衍射分析确定。未溶剂化的Al(C₆F₅)₃并非如预期那样与-C₆F₅基团中看似更容易接近的间位和对位氟原子形成AlF接触，而是两个Al(C₆F₅)₃分子形成一种二聚体结构，在一个分子的Al中心与另一个分子的-C₆F₅基团的邻位氟原子之间存在双重AlF相互作用。这种相互作用模式显然与固态下未溶剂化的Al(C₆F₅)₃的热敏感性和冲击敏感性有关。为了与B(C₆F₅)₃/二茂铁受阻路易斯对体系进行比较，还研究了Al(C₆F₅)₃与二茂铁之间的络合作用，结果得到一种稳定的加合物，它是通过Al与其中一个C-Cp原子的η(1)-配位形成的，类似于铝烷-甲苯或苯络合物。
