Jákó Szabolcs, Lupan Alexandru, Kun Attila-Zsolt, King R Bruce
Department of Chemistry and Chemical Engineering, Hungarian Line of Study, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University , Cluj-Napoca 400084, Romania.
Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University , Cluj-Napoca 400084, Romania.
Inorg Chem. 2017 Jan 3;56(1):351-358. doi: 10.1021/acs.inorgchem.6b02281. Epub 2016 Dec 12.
The structures and energetics of the dimetallaboranes CpMBH (n = 8, 9, 10, 11, 12; M = Co, Rh, Ir; Cp = η-CH) were studied using density functional theory. The lowest energy CpMBH and CpMBH structures are chiral C structures based on the corresponding closo deltahedra, namely the bisdisphenoid and the tricapped trigonal prism. The permethylated iridaboranes CpIrBH and CpIrBH (Cp* = η-MeC) were synthesized by Ghosh and co-workers. However, they were found by X-ray crystallography to have nondeltahedral structures containing a quadrilateral face, namely a bicapped trigonal prism and a capped square antiprism for the 8- and 9-vertex systems, respectively. These structures correspond to a mean of the two opposite enantiomers and can also represent the "square" intermediate in the interconversion of the two enantiomers. The lowest energy structures for the 10-vertex CpMBH systems are two isocloso deltahedra with one metal atom at a degree 6 vertex and the other metal atom at a degree 5 vertex. Both isomers have been realized experimentally for CpIrBH. The lowest energy structures for the 11-vertex CpMBH systems have central closo/isocloso deltahedra with one metal atom at a degree 6 vertex and the other metal atom at a nonadjacent degree 5 vertex. This structure type has been found experimentally in both the rhodaboranes and iridaboranes CpMBH (M = Rh, Ir). The lowest energy structures for the 12-vertex systems CpMBH (M = Co, Rh, Ir) are deltahedra with two adjacent degree 6 vertices for the metal atoms. This type of structure is found experimentally in the rhodium complexes CpRhBH(OH) (n = 1, 2).
利用密度泛函理论研究了二金属硼烷CpMBH（n = 8、9、10、11、12；M = Co、Rh、Ir；Cp = η-CH）的结构和能量。能量最低的CpMBH和CpMBH结构是基于相应封闭 delta 面体的手性C结构，即双蝶形和三帽三棱柱体。Ghosh及其同事合成了全甲基化铱硼烷CpIrBH和CpIrBH（Cp* = η-MeC）。然而，通过X射线晶体学发现它们具有包含四边形面的非 delta 面体结构，对于8顶点和9顶点体系，分别为双帽三棱柱体和帽盖四方反棱柱体。这些结构对应于两种相反对映体的平均值，也可以代表两种对映体相互转化中的“方形”中间体。10顶点CpMBH体系的能量最低结构是两个等封闭delta面体，一个金属原子位于6度顶点，另一个金属原子位于5度顶点。对于CpIrBH，这两种异构体均已通过实验实现。11顶点CpMBH体系的能量最低结构具有中心封闭/等封闭delta面体，一个金属原子位于6度顶点，另一个金属原子位于不相邻的5度顶点。这种结构类型已在铑硼烷和铱硼烷CpMBH（M = Rh，Ir）中通过实验发现。12顶点体系CpMBH（M = Co，Rh，Ir）的能量最低结构是金属原子具有两个相邻6度顶点的delta面体。这种结构类型在铑配合物CpRhBH(OH)（n = 1，2）中通过实验发现。
