PDF(Pubmed)
Abstract：
Planar tetracoordinate silicon, germanium, tin, and lead (ptSi/Ge/Sn/Pb) species are scarce and exotic. Here, we report a series of penta-atomic ptSi/Ge/Sn/Pb XB2Bi2 (X = Si, Ge, Sn, Pb) clusters with 20 valence electrons (VEs). Ternary XB2Bi2 (X = Si, Ge, Sn, Pb) clusters possess beautiful fan-shaped structures, with a Bi-B-B-Bi chain surrounding the central X core. The unbiased density functional theory (DFT) searches and high-level CCSD(T) calculations reveal that these ptSi/Ge/Sn/Pb species are the global minima on their potential energy surfaces. Born-Oppenheimer molecular dynamics (BOMD) simulations indicate that XB2Bi2 (X = Si, Ge, Sn, Pb) clusters are robust. Bonding analyses indicate that 20 VEs are perfect for the ptX XB2Bi2 (X = Si, Ge, Sn, Pb): two lone pairs of Bi atoms; one 5c-2e π, and three σ bonds (two Bi-X 2c-2e and one B-X-B 3c-2e bonds) between the ligands and X atom; three 2c-2e σ bonds and one delocalized 4c-2e π bond between the ligands. The ptSi/Ge/Sn/Pb XB2Bi2 (X = Si, Ge, Sn, Pb) clusters possess 2π/2σ double aromaticity, according to the (4n + 2) Hückel rule.
摘要：
平面四坐标硅，锗,锡，和铅（ptSi/Ge/Sn/Pb）物种稀缺且奇特。这里,我们报告了一系列五原子ptSi/Ge/Sn/PbXB2Bi2(X=Si，Ge,Sn,Pb)团簇具有20个价电子(VEs)。三元XB2Bi2(X=Si,Ge,Sn,Pb)团簇具有美丽的扇形结构，具有围绕中心X核的Bi-B-B-Bi链。无偏密度泛函理论（DFT）搜索和高级CCSD（T）计算表明，这些ptSi/Ge/Sn/Pb物种是其势能面上的全局最小值。Born-Oppenheimer分子动力学(BOMD)模拟表明XB2Bi2(X=Si，Ge,Sn,Pb)团簇是稳健的。结合分析表明，对于ptXXB2Bi2（X=Si，Ge,Sn,Pb）：两对孤对偶Bi原子；一个5c-2eπ，配体和X原子之间的三个σ键（两个Bi-X2c-2e和一个B-X-B3c-2e键）；配体之间的三个2c-2eσ键和一个离域4c-2eπ键。ptSi/Ge/Sn/PbXB2Bi2(X=Si,Ge,Sn,Pb)团簇具有2π/2σ双芳香性，根据（4n2）Hückel规则。
