含有平面六配位碳的第二及第三过渡系金属夹心配合物密度泛函理论研究

A Density Function Theory Investigation on Sandwich-type Heavy Transition Metal Complexes(B_6C)_2M Containing Planar Hexacoordinate Carbons

采用密度泛函方法研究了含有平面六配位碳(PhC)和平面六配位氮(PhN)的第二和第三过渡系金属夹心化合物(B6X)2M(X=C,N;M=Ru,Rh,Pd,Os,Ir,Pt)的几何结构和电子性质.具有6个π电子的B6C2-及B6N-结构单元体是ⅧB族过渡金属的良好配体,它们与过渡金属中心M形成符合18电子规则的交错型夹心化合物D6d(B6X)2M,其中PhC(或PhN)与M共线,形成体系的六重对称轴.具有近似单位负电荷的非金属中心X满足八隅律规则,其W iberg键级约为WB IPhC≈4及WB IPhN≈3.

A density functional theory（DFT） investigation on ⅧB second- and third-row transition metal complexes（B6X）2M（X =C, N; M = Ru, Rh, Pd, Os, Ir, Pt） containing quasi-planar hexacoordinate carbon （PhC） or nitrogen（PhN） was presented in this work. The 6π B6C^2- and B6N- units turned out to be effective aromatic ligands to coordinate Ⅷ B transition metal centers to form 18-electron staggered sandwich-type complexes, in which the colinear terminal PhCs（or PhNs） and the transition metal center M form the six-fold molecular axes of the systems. The planar hexacoordinate nonmetal centers X carrying approximately unitary negative charges follow the octet rule, with the Wiberg bond orders of WBIphc≈4 and WBIphN≈3. These theoretical predictions are expected to be confirmed in experiments to open a new branch of chemistry on hexacoordinate carbons and other nonmetals. planar hexacoordinate carbons and other nonmetals.