SYNTHESIS AND CHARACTERIZATION OF NEW HYPHO-DITHIABORANE CLUSTERS - STRUCTURAL AND BONDING LINKS BETWEEN ELECTRON-DEFICIENT AND ELECTRON-PRECISE CAGE SYSTEMS
SYNTHESIS AND CHARACTERIZATION OF NEW HYPHO-DITHIABORANE CLUSTERS - STRUCTURAL AND BONDING LINKS BETWEEN ELECTRON-DEFICIENT AND ELECTRON-PRECISE CAGE SYSTEMS
复制标题
DOI：
10.1021/ja00191a026
复制
发表时间：
1989-04-26
影响因子：
15
通讯作者：
SNEDDON, LG
中科院分区：
文献类型：
--
作者：
KANG, SO;SNEDDON, LG
通过ANZC/Mo-S2B7H8-与过量丙酮反应，高产率地合成了二硫代硼烷阴离子/yP/IoS2B6H9(I)。I与过量的甲基碘反应生成AypZzo-2，3-(CH3)2-2，3-S2B6H8(II)。单晶X-射线衍射法测定了该化合物的结构，结果表明该化合物具有8个顶点的网笼构型，可以通过去除3个顶点从一个八面体衍生而来。或者，II可以被认为是六硼烷(LO)的桥联衍生物。II的晶体数据：空间群R2，/c；Z=4；a=5.753(1)，6=7.293(1)，c=23.380(3)A；？=92.087(2)；V=92.087 A1 23。对于1394次反射，通过全矩阵最小二乘法改进结构，最终R为0.051，RW为0.071，其中F02>；3ct(F02)。I与二碘甲烷反应，高产率地合成了亚甲基-1-CH2，5-S2B6H8(III)。单晶X-射线结构测定表明，它具有一个从二十面体通过去除三个顶点而来的九个顶点的网笼几何结构。此外，观察到笼子有一个独特的CH2单元，连接两个硫原子形成一个开放的五元体面。晶胞参数：空间群C/c，Z=4，a=6.9538(6)，b=11.850(2)，c=9.9202(6)A，B=104.689(6)，V=9.9202(6)。通过全矩阵最小二乘法对结构进行了优化，最终的R为0.042，RW为0.055，这635个反射具有FQ2和GT；3a(F02)。二硫硼烷阴离子Hypho-S2B(Fif)与BH3-THF反应生成二硫代硼酸根阴离子Hypho-S2B1}I“(IV)。或者，可以通过Arac/mo-S2B7H8~与BFI3-THF反应或通过Arachno-6，8-S2B7H9与NaBFI4直接反应以更高的产率制备IV。IV质子化得到中性化合物AYP/io-7，8-S2B7Hn(V)，产率较高。V与III是等电子的，根据光谱数据，建议采用类似的环状几何构型，其中BH2单元连接五元面上的两个硫原子，在B10和BLL硼之间增加一个氢桥。大多数多面体硼烷被发现是闭合、Nido或Arachno电子类别的成员，分别含有n+1，+2，或n4-3骨架电子对(其中=笼子原子的数量)。尽管已知有许多例外，但归入这些类别的化合物通常具有可预测的结构，分别基于闭合的三角体或缺少一个或两个顶点的三角体。1连电子类的成员要少得多，也就是含有n+4个骨架电子的团簇。例子包括B6H10(PMe3)2、2 B5H12“、3
The dithiaborane anion/¡ yp/ioS2B6H9_ (I) was produced in high yield by the reaction of anzc/mo-S2B7H8-with excess acetone. Subsequent reaction of I with excess methyl iodide gave AypZzo-2, 3-(CH3) 2-2, 3-S2B6H8 (II). A single-crystal X-ray determination of II showed that the compound has an eight-vertex hypho cage geometry, which can be derived from an octadecahedron by removing three vertices. Alternatively, II can be considered a dibridged derivative of hexaborane (lO). Crystal data for II: space group R2,/c; Z= 4; a= 5.753 (1), 6= 7.293 (1), c= 23.380 (3) A; ß= 92.087 (2); V= 980.2 A1 23. The structure was refined by full-matrix least squares to a final R of 0.051 and Rw of 0.071 for the 1394 reflections, which had F02> 3ct (F02). The reaction of I with diiodomethane gave hypho-1-CH2-2, 5-S2B6H8 (III) in good yield. A single-crystal X-ray structural determination of III showed that it has a nine-vertex hypho cage geometry derived from an icosahedron by removal of three vertices. Furthermore, the cage is observed to have a unique CH2 unit bridging the two sulfur atoms forming an open five-membered face. Crystal data for III: space group C/c; Z= 4; a= 6.9538 (6), b= 11.850 (2), c= 9.9202 (6) A; ß= 104.689 (6); V= 790.7 A3. The structure was refined by full-matrix least squares to a final R of 0.042 and Rw of 0.055 for the 635 reflections, which had FQ2> 3a (F02). The dithiaborane anion hypho-S2B1} i¡(¡~(IV) was produced by the reaction of hypho-S2B (fif with BH3-THF. Alternatively, IV may be prepared in better yields either by the reaction of arac/mo-S2B7H8~ with BFI3-THF or by the direct reaction of arachno-6, 8-S2B7H9 with NaBFI4. Protonationof IV gives the neutral compound Ayp/io-7, 8-S2B7Hn (V) in good yield. V is isoelectronic withIII and, on the basis of the spectroscopic data, is proposed to adopt a similar hypho cage geometry in which a BH2 unit bridges the two sulfur atoms on the five-membered face with an additional hydrogen bridgebetween the B10 and Bll borons.Most polyhedral boranes have been found to be members of the closo, nido, or arachno electronic classes, containing n+ 1,+ 2, or n 4-3 skeletal electron pairs, respectively (where= the numberof cage atoms). Although manyexceptions are known, compounds that fall into these classes generally have predictable structures based on closed deltahedra or deltahedra missing one or two vertices, respectively. 1 There are many fewer members of the hypho electronic class, that is clusters containing n+ 4 skeletal electrons. Examples include B6H10 (PMe3) 2, 2 B5H12 “, 3