从头计算方法比较研究B_2Au_4,Al_2Au_4和BAlAu_4的几何和电子结构(英文)

A Comparative Ab initio Study of the Geometric and Electronic Structures of B_2Au_4, Al_2Au_4 and BAlAu_4

Au/H相似性的研究是现代化学中的一个热门话题.我们从理论上报道Au/H相似的新成员:共价化合物B2Au4,离子化合物Al2Au4和BAl Au4.采用密度泛函和波函数理论方法对比研究了缺电子体系B2Au4、Al2Au4和BAl Au4的几何和电子结构.详细讨论了它们基态结构的轨道、适应性自然密度划分(Ad NDP)和电子局域函数(ELF)分析.计算结果表明稍微扭曲变形的C2B2Au4是基态结构,在这个共价化合物中含有两个B―Au―B三中心二电子(3c-2e)键.然而C3vAl+(Al Au4)-和C3vAl+(BAu4)-被研究证明是含有三个X―Au―Al三中心二电子键的类盐化合物(在Al2Au4中X=Al,BAl Au4中X=B).Al2Au4和BAl Au4是至今为止首例报道的在离子缺电子体系中含有金桥键的化合物.同时计算了B2Au4-、Al2Au4-和BAl Au4-阴离子基态结构的绝热剥离能和垂直剥离能,为实验表征提供依据.文中报道的金桥键为共价键和离子键相结合的缺电子体系提供了一个有趣的键合模式,有助于设计含有高度分散金原子的新材料和催化剂.

Au/H similarity is a hot topic in chemistry. Here, we report the theoretical prediction of new members of the Au/H analogy family：covalent B2Au4, ionic Al2Au4, and BAlAu4. A comparative study of the geometric and electronic structures of electron-deficient B2Au4, Al2Au4, and BAlAu4 was performed based on density and wave functional theories. Detailed orbital analyses, adaptive natural density partitioning （AdNDP）, and electron localization function （ELF） analyses were performed. Ab initio theoretical evidence strongly suggests that the ground state of slightly distorted C2 B2Au4 is a covalent complex containing two B―Au―B three centers-two electrons （3c-2e） bonds. Unexpectedly, C3v Al＋（AlAu4）-and C3v Al＋（BAu4）-are predicted to have a salt-like composition with three X―Au―Al 3c-2e bonds （X=Al in Al2Au4, X=B in BAlAu4）. Al2Au4 and BAlAu4 represent the first examples of bridging gold bonds in ionic-deficient systems. The adiabatic and vertical detachment energies of the anions were calculated to facilitate their future experimental characterization. Bridging gold addressed in this work provides an interesting bonding mode for covalent and ionic-deficient systems, and may aid in designing new materials and catalysts with highly dispersed Au atoms.