应用密度泛函理论（DFT ）和B3LYP/6-31＋G**方法，对金属Cr9团簇与DNA/RNA的碱基的相互作用规律进行了研究。运用势能面扫描的方法和计算各种复合体的结合能，得到了C r9团簇在各碱基的不同的点附近与碱基形成复合体时，其复合体的稳定性大小的分布情况。发现C r9团簇通过接近碱基的环上氮原子及氧原子与其结合时，所构成的C r9团簇-碱基复合体比较稳定。通过对复合体的前线轨道的分析，找出了各种C r9团簇-碱基复合体的结合能大小不同的原因。研究结果表明，结合能比较大的Cr9团簇-碱基复合体的最高占有轨道（HOMO）由Cr- d和N - p（或O - p）轨道杂化而成，共价相互作用为团簇与碱基结合的主要因素。结合能较小的Cr9团簇-碱基复合体的HOMO中没有团簇与碱基的电子云的重叠，范德瓦尔斯力是两者结合的主要因素。本文的研究对揭示金属铬团簇对生物体影响的规律，以及对探测和监控生物体中铬团簇的都有着要的意义。%The pattern of interaction between Cr9 Clusters and nucleobases was studied using Density Functional Theory (DFT) and B3LYP/6-31+G* * method .By applying the potential energy surface scanning method and the calculation of the binding energy ,the distribution of the degree of stability of the Cr 9 cluster -base conjugate complexes was obtained .It was found that Cr9 cluster prefer to bind with the ring nitrogen atom and the oxygen at-om of the nucleobases .The analyzing of the frontier orbits showed that for complexes with greater binding ener-gies ,their HOMOs were the hybridization of the Cr -d and N/O-p orbits and covalent interaction is main cause of the binding ;for the complexes with smaller binding energies ,no overlapping exists between Cr9 cluster and base , and the van de Waal’s interaction is the main cause of their binding .This study has significant potential influence on both revealing the impact of Cr clusters on living organisms and detecting Cr c lusters within organisms .
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