Structures and chemical bonding of boron-based B12O and B11Au clusters. A counterexample in boronyl chemistry
Structures and chemical bonding of boron-based B12O and B11Au clusters. A counterexample in boronyl chemistry
复制标题
硼基 B12O 和 B11Au 团簇的结构和化学键合。
DOI：
10.1039/d2cp01277d
复制
发表时间：
2022-04-25
影响因子：
3.3
通讯作者：
Zhai, Hua-Jin
中科院分区：
文献类型：
--
作者：
Li, Peng-Fei;Zhai, Hua-Jin
氧化硼簇合物具有结构多样性和独特的化学键，最近的文献表明，硼基络合物是富硼氧化物簇合物的主要成分。本文给出了硼基化学中的一个反例。利用全局结构搜索、电子结构计算和化学键分析，我们将报道两个基于硼的准平面或平面团簇的计算设计：B12O和B11Au。与预期相反，B120O星系团具有圆形准平面形状，外围有一座B-O-B桥，类似于裸露的B-12星系团。它不含硼基配体。在单点CCSD(T)水平上，异构化的硼基络合物的能量要高出10.32kcal(-1)。相反，B11Au团簇表现出正常的行为，具有细长的B-11部分和末端的Au配体。化学键分析表明，环状B12O团簇中存在三重pi/sigma芳香性，包括全局6pi芳香性，以及空间上孤立的内2sigma芳香性和外10sigma芳香性。B12O团簇的3倍6pi/2sigma/10sigma芳香性是其稳定性的基础。对于裸露的B-12团簇及其衍生物，这种成键图像是未知的。细长的B11Au团簇具有相互冲突的pi/sigma芳香性(电子计数为6pi与8sigma)。在离域pi/sigma键方面，B12O团簇实际上与裸露的B-12团簇是等电子的，这继承了后者的结构和电子稳健性。
Boron oxide clusters have structural diversity and unique chemical bonding, and recent literature has shown that boronyl complexes dominate boron-rich oxide clusters. A counterexample in boronyl chemistry is presented in this work. Using global structural searches, electronic structure calculations, and chemical bonding analyses, we shall report on the computational design of two boron-based quasi-planar or planar clusters: B12O and B11Au. Contrary to expectation, the B12O cluster has a circular quasi-planar shape with a peripheral B-O-B bridge, which resembles bare B-12 cluster. It does not contain a boronyl ligand. The isomeric boronyl complex turns out to be 10.32 kcal mol(-1) higher in energy at the single-point CCSD(T) level. In contrast, B11Au cluster behaves normally with an elongated B-11 moiety and a terminal Au ligand. Chemical bonding analyses reveal three-fold pi/sigma aromaticity in circular B12O cluster, including global 6 pi aromaticity, as well as spatially isolated inner 2 sigma aromaticity and outer 10 sigma aromaticity. The three-fold 6 pi/2 sigma/10 sigma aromaticity underlies the stability of B12O cluster. This bonding picture is unknown for bare B-12 cluster and its derivatives. The elongated B11Au cluster has conflicting pi/sigma aromaticity (with 6 pi versus 8 sigma electron-counting). The B12O cluster is actually isoelectronic with bare B-12 cluster in terms of delocalized pi/sigma bonding, which inherits the structural and electronic robustness of the latter.