(1,3,5-C_3P_3H_3)M与(1,3,5-C_3P_3H_3)_2M(M=Ti,V,Cr)配合物的结构与芳香性

Structures and Aromaticities of Complexes(1,3,5-C_3P_3H_3)M and(1,3,5-C_3P_3H_3)_2M(i=Ti,V,Cr)

运用密度泛函理论研究了（1，3，5-C3P3H3）M和（1，3，5-C3P3H3）：M（M=Ti,V,Cr）的结构、键合能以及芳香性．结果表明：低自旋的（1，3，5-C3P3H3）M和（1，3，5-C3P3H3）：M基态结构分别具有C3v，和D3n对称性．金属与配体间为共价作用，二者之间存在σ、π和δ种成键方式．V的三明治配合物的解离方式与Ti和Cr的三明治配合物不同，前者为分步解离，后两者则为一步解离．其中（1，3，5-C3P3H3）2Cr（D3n）的第-解离能最大，配合物最稳定．这些三明治和半三明治配合物都具有中心芳香性、内芳香性和外芳香性，且中心芳香性均大于自由配体（1，3，5-C3P3H3）的中心芳香性．芳香性主要贡献来源于臌和金属原子的孤对电子．内芳香性按照Ti、V、Cr的顺序依次增大，且内芳香性明显要大于外芳香性．高自旋的半三明治（1，3,5-C3P3H3）Ti（C3，5A1）与单重态（1，3，5-C3P3H3）Ti（C3v,1A1）相比，配体的变形性增大，稳定性增加，且C平面中心芳香性和内芳香性均增大，但P平面的中心芳香性却降低．

The equilibrium geometries, binding energies and aromaticities of （1,3,5-C3P3H3）M and （1,3, 5-C3PsH3）2M （M=Ti, V, Cr） were calculated by density function theory. The results indicate that the ground states of （1,3,5-C3P3H3）M and （1,3,5-C3P3H3）2M have C3v and D3h symmetries, respectively. The main interactions between the ligands and metal are covalent interactions featuring three types of interactions represented as σ,π and δ between the ligands and the metal. The dissociation method of the/igands and the metal in sandwich V complexes is different from that of Ti and Cr complexes, i.e., the former consists of two steps and the latter consists of one step. The first dissociation energy of （1,3,5-C3P3H3）2Cr is the largest and so it is the most stable one. These complexes have central, inner and outer aromaticities and the central-aromaticities of the complexes are stronger than that of （1,3,5-C3P3H3）. The contributions of aromaticities is dominated by π bonds and the lone pair electronics of the metal atom. The inner-aromaticities of the complexes increase in the following order： Ti, V, Cr, and they are evidentlystronger than the outer-aromaticities. Compared with （1,3,5-C3P3H3）Ti （C3v, 1A,） the distortion of the ligands for the high spin multiplicity of half-sandwich （1,3,5-C3P3H3）Ti （C3, 5A1） is larger and more stable. The central and inner aromaticities in the C plane of the high spin multiplicity half-sandwich （1,3,5-C3P3H3）Ti （C3, 5A1） are stronger than that of （1,3,5-C3P3H3）Ti （C3v, 1A1）, but the central aromaticity in the P plane is weaker.