摘要
利用密度泛函理论在B3LYP/6-311G*水平上对碱土金属叠氮化合物(MgN6)n(n=1～5)团簇各种可能构型进行了几何优化,预测了各团簇的最稳定结构。并对最稳定结构的成键特性、电荷分布、振动特性及稳定性进行理论研究。结果表明,叠氮化合物中叠氮基以直线型存在,MgN6团簇最稳定结构为直线型;(MgN6)2团簇最稳定结构为Mg2N2四元环平面结构;(MgN6)n(n=3～5)团簇最稳定结构是由2个叠氮基与2个Mg原子首先构成近似菱形,再由近似菱形延伸形成的链状结构。叠氮基中间的N原子显示正电性,两端的N原子显示负电性,且与Mg直接作用的N原子负电性更强,金属Mg原子和N原子之间形成很强的离子键。(MgN6)n(n=1～5)团簇最稳定结构的IR光谱分为4个部分,其最强振动峰均位于2209～2313cm-1,振动模式为叠氮基中N-N键的反对称伸缩振动。稳定性分析显示,(MgN6)3和(MgN6)5团簇相对于其他团簇较为稳定。
Possible geometrical structures and relative stability of Alkaline-earth metal azides （MgN6）n （n=1～5） clusters are studied by using the hybrid density functional theory （B3LYP） with 6-311G＊ basis sets. For the most stable isomers of （MgN6）n （n=1～5） clusters,the bond properties,charge distributions,vibrational properties,and stability are analyzed. The calculated results show that azido in azides has linear structure,most of the optimized MgN6 has linear structure,most of the optimized （MgN6）2 has plane structure of Mg2N2 ring,and most of the optimized （MgN6）n （n=3～5） have chain structure of perpendicularity of approximate diamond. The middle N atoms of azido show negative,the N atoms at both ends of azido show positive,and the N atoms effected with Mg atoms directly show more negative. Between the Mg atoms and N atoms exist a strong ionic bond. The IR spectra of the most optimized （MgN6）n （n=1～5） clusters have four vibrational sections,the whole strongest vibrational peak lies in 2 209～2 313 cm^-1,and the vibrational mode is anti-symmetric stretching vibration of N-N bonds in azido. Stability analysis shows that （MgN6）3 and （MgN6）5 clusters relative to other clusters are more stable.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2010年第8期1361-1369,共9页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.10547007)
兰州理工大学博士基金(No.BS10200901)资助项目
