π-Bonding in B-O ring species:: Lewis acidity of Me3B3O3, synthesis of amine Me3B3O3 adducts, and the crystal and molecular structure of Me3B3O•3NH2iBu•MeB(OH)2
π-Bonding in B-O ring species:: Lewis acidity of Me3B3O3, synthesis of amine Me3B3O3 adducts, and the crystal and molecular structure of Me3B3O•3NH2iBu•MeB(OH)2
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DOI：
10.1016/s0022-328x(99)00182-5
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发表时间：
1999-08-01
影响因子：
2.3
通讯作者：
Varma, KS
中科院分区：
文献类型：
--
作者：
Beckett, MA;Brassington, DS;Varma, KS
合成和表征（m. p.，元素分析，IR，NMR）的一些以前未报道的Me 3B 3 O3。描述了L加合物（L=哌啶、异丁胺、吗啉、3-甲基吡啶、苄胺）。（Me_3B_3O_3NH_2Bu）-Bu_1的晶体和分子结构。用X射线单晶衍射法测定了MeB（OH）（2）的晶体结构。该结构揭示了MeB（OH）（2）与三甲基环硼氧烷加合物Me 3B 3 O3的六元B3 O3环的环O原子之间的不寻常的氢键相互作用。（NH2Bu）-Bu-i.氢键的方向强烈地表明该O原子的sp（2）杂化。本文用Gutmann方法估算了Me_3B_3O_3，Ph_3B_3O_3，1，3，5-Ph_3B_3N_3Me_3和1，3，5-Ph_3C_6H_3的刘易斯酸性，并用这些环系中的相对K键强度解释了计算结果。(C)1999年Elsevier Science S.A. All rights reserved.
The synthesis and characterisation (m.p., elemental analysis, IR, NMR) of some previously unreported Me3B3O3. L adducts (L=piperidine, isobutylamine, morpholine, 3-picoline, benzylamine) are described. The crystal and molecular structure of (Me3B3O3NH2Bu)-Bu-i . MeB(OH)(2) has been determined by a single-crystal X-ray diffraction study. The structure reveals an unusual H-bond interaction between MeB(OH)(2) and a ring O atom of the six-membered B3O3 ring of the trimethylboroxine adduct, Me3B3O3. (NH2Bu)-Bu-i. The direction of the H-bond strongly suggests sp(2) hybridisation for this O atom. The Lewis acidity of Me3B3O3, Ph3B3O3, 1,3,5-Ph3B3N3Me3 and 1,3,5-Ph3C6H3 have been estimated by Gutmann's method and data interpreted in terms of relative K-bonding strength within these ring systems. (C) 1999 Elsevier Science S.A. All rights reserved.