[Cr_2CoO(O_2CCH_3)_6Py_3]·Py簇合物的分子结构和电子结构

The Molecular and Electronic Structure of Cluster Compound [Cr_2CoO(O_2CCH_3)_6Py_3] ·Py

合成并测定了标题化合物的分子结构,Ca空间群,a=2.1933(2)nm,b=1.2447(3)nm,c=1.5912(5)nm,β=117.02(2)°,I＇=3.8679 nm^3,Z=4,最后根据I>3G(I)的2849个独立衍射点的强度数据,把结构精修到R=0.036.在晶体结构测定基础上进行了EHMO计算,以研究其簇骼成键性质,结果表明,该分子虽不存在金属-金属键,但M与μ-O之间除了σ键外,还存在四中心d-ρπ键,它是该类化合物稳定的主要因素。

The titled compound was prepared and its molecular structure was determined. Space group Cc, a = 2. 1933(2) nm, 6=1. 2447(3) nm, c=1. 5912(5) nm, β=117. 02(2), K = 3. 8679 nm3, Z=4, Dc=1. 46 g/cm3, and R=0. 036 for 2849 reflections with I>3σ(I). To study the bonding character of the skeleton its electronic structure was calculated by EHMO method. The results indicate that although there is not M-M bond, it is important for molecular stability to form four-centre d-pπ bond beween M and μ3-O besides a bond.