(X_2InN_3)_n(n=1-3;X=F,Cl,Br,I)簇合物的密度泛函理论研究

Studies on Clusters (X_2InN_3)_n(n=1-3;X=F,Cl,Br,I) with Density Functional Theory

采用密度泛函理论B3LYP/Lanl2dz方法,计算研究了(X2InN3)n(n=1-3;X=F,Cl,Br,I)簇合物的几何构型、电子结构和聚合反应热力学性质,讨论了取代基效应。研究表明,二聚体(X2InN3)2和三聚体(X2InN3)3(X=F,Cl,Br,I)的优化几何构型均为由不同子体系的叠氮基α-N和In原子相连而成的环状结构。在卤原子(X)取代簇合物中,取代位附近的键长、键角和原子电荷改变较大。由前线轨道能隙ΔEgap和反应焓变ΔH0可见,同类簇合物的稳定性排序为(F2InN3)n>(Cl2InN3)n>(Br2InN3)n>(I2InN3)n(n=1-3)。求得298.2 K温度下聚合反应的吉布斯自由能变化ΔG0均为负值,表明反应可自发进行。此外,还发现簇合物的性质随聚合度n增加的变化规律。

The geometric configurations,electronic structures and thermodynamic properties of polymerizations are studied at the B3LYP/Lanl2dz level of density functional theory（DFT）.The effect of substituents on the above properties is discussed.The calculated results show that the optimized dimer（X2InN3）2 and trimer（X2InN3）3（X=F,Cl,Br,I） all possess cyclic structure formed by In atoms bridged by the α-nitrogen of the azide groups.Halogen X substitution largely affects the bond lengths,bond angles,and charge distributions on the atoms near the substitution positions.From the calculation of the energy gap ΔEgap and the oligomerization enthalpies ΔH0,it is indicated that the stability order is as follows：（F2InN3）n（Cl2InN3）n（Br2InN3）n（I2InN3）n（n=1-3）.The Gibbs energies ΔG0 of the oligomerizations at 298.2 K are negative,which indicates the oligomerization can occur spontaneously.The change rule of the properties of the clusters with the increase of the oligomerization degree n is discovered.