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, Romania.
Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University , Cluj-Napoca, Romania.
Inorg Chem. 2017 Sep 18;56(18):11059-11065. doi: 10.1021/acs.inorgchem.7b01422. Epub 2017 Sep 6.
The chromadicarbaboranes CpCrCBH (8 ≤ n ≤ 12) are of interest in providing stable paramagnetic deltahedral metallaboranes among which the 12-vertex CpCrCBH has been synthesized by Hawthorne and co-workers. Density functional theory shows that the lowest-energy such structures are quartet spin-state Cr(III) structures in which the central CrCB units exhibit most spherical closo deltahedral geometries similar to those found in the borane dianions BH. Higher-energy doublet CpCrCBH (8 ≤ n ≤ 11) structures are found exhibiting central CrCB isocloso deltahedral geometries, thereby providing a degree 6 vertex for the chromium atom. The lowest-energy CpCrCBH (8 ≤ n ≤ 11) structures all have both carbon atoms at degree 4 vertices. However, the lowest-energy CpCrCBH structures all have central CrCB icosahedra and thus lack degree 4 vertices for the carbon atoms. For all of the CpCrCBH (8 ≤ n ≤ 12) systems the lowest-energy isomers are those with the maximum number of Cr-C edges in contrast to the related CpCoCBH systems.
色度碳硼烷CpCrCBH（8≤n≤12）在提供稳定的顺磁性多面体金属硼烷方面具有重要意义，其中12顶点的CpCrCBH已由霍桑及其同事合成。密度泛函理论表明，此类结构中能量最低的是四重态自旋态Cr(III)结构，其中中心CrCB单元呈现出最接近球形的闭合多面体几何形状，类似于硼烷二负离子BH中的几何形状。发现能量较高的二重态CpCrCBH（8≤n≤11）结构呈现中心CrCB等闭合多面体几何形状，从而为铬原子提供了一个6度顶点。能量最低的CpCrCBH（8≤n≤11）结构中，两个碳原子均位于4度顶点。然而，能量最低的CpCrCBH结构均具有中心CrCB二十面体，因此碳原子没有4度顶点。对于所有CpCrCBH（8≤n≤12）体系，与相关的CpCoCBH体系相比，能量最低的异构体是具有最多Cr-C键的异构体。
