Nanocluster Laboratory, Institute of Molecular Science, Shanxi University, Taiyuan 030006, China.
Molecules. 2023 Jan 17;28(3):942. doi: 10.3390/molecules28030942.
Hypercoordinate transition-metal species are mainly dominated by the 18-valence-electron (18ve) counting. Herein, we report ternary MAlS (M = Ni, Pd, Pt) clusters with the planar hexacoordinate metal (phM) centers, which feature 16ve counting instead of the classic 18ve rule. These global-minimum clusters are established via unbiased global searches, followed by PBE0 and single-point CCSD(T) calculations. The phM MAl units are stabilized by six peripheral bridging S atoms in these star-like species. Chemical bonding analyses reveal that there are 10 delocalized electrons around the phM center, which can render the aromaticity according to the (4 + 2) Hückel rule. It is worth noting that adding an (or two) electron(s) to its π-type lowest unoccupied molecular orbital (LUMO) will make the system unstable.
高次坐标过渡金属物种主要由 18 价电子计数（18ve）支配。在此，我们报道了具有平面六配位金属（phM）中心的三元 MAlS（M = Ni、Pd、Pt）团簇，其特征为 16ve 计数，而不是经典的 18ve 规则。这些全局最小团簇是通过无偏全局搜索建立的，然后进行 PBE0 和单点 CCSD(T)计算。在这些星型物种中，phM MAl 单元由六个外围桥接 S 原子稳定。化学键分析表明，phM 中心周围有 10 个离域电子，根据（4 + 2）Hückel 规则可以赋予其芳香性。值得注意的是，向其π型最低未占据分子轨道（LUMO）添加一个（或两个）电子会使系统不稳定。
