铁铜双核羰基簇合物结构的理论研究

DFT study on the structures of FeCu binuclear carbonyl cluster

采用密度泛函理论BPW91方法在6-311+G(d)基组水平上,对FeCu团簇吸附CO过程中可能的几何结构和电子态进行了系统研究.计算结果表明:FeCu双原子团簇饱和吸附CO分子数是7,配位过程均为放热反应,吸附能最大的结构是FeCu(CO)_(1).金属原子满足18电子规则,对CO的吸附位置起主要决定作用,即CO配位由于遵循18电子规律,即Fe原子上形成Fe(CO)_(4)Cu之后CO与Cu原子发生配位形成Fe(CO)_(4)Cu(CO)_(3).各配合物中Fe电荷密度最大的结构是Fe(CO)_(4)Cu(CO)_(1), Cu电荷密度最大的结构Fe(CO)_(4)Cu(CO)_(3).

The geometries and electronic states of FeCu binuclear carbonyl clusters have been investigated by using the BPW91 of density functional theory, with the 6-311+G(d) basis set employed for all atoms. The calculation results indicate that the saturated adsorption amount of the FeCu cluster is 7, all CO coordination steps are exothermic, the largest CO coordination energy(-199.0 kJ·mol-1) is found for FeCu(CO)_(1). According to the adsorption of CO on the clusters, we find out that CO coordination prefers to take place on Fe atom to form Fe(CO)_(4)Cu which follows the 18-electron rule and then on the Cu atom to form Fe(CO)_(4)Cu(CO)_(3). In the iron-copper carbonyl systems, the structures of largest spin density for Fe and Cu atoms are FeCu(CO)5 and FeCu(CO)7, respectively.