X...Y(X=LiF,NH_3,H_2O;Y=HF,LiF)复合物中锂键、氢键的理论计算  

Theoretical Studies on Hydrogen Bond and Lithium Bond in X…Y(X = LiF,NH_3,H_2O;Y=HF,LiF) Complexes

作　　者：刘雅萌 李俊 高爱舫 甄岩[4] 

机构地区：[1]北京工业大学生命科学与生物工程学院环境与病毒肿瘤学北京市重点实验室,北京100124 [2]广东第二师范学院化学系,广州510303 [3]河北地质大学水资源与环境学院,石家庄050031 [4]北京工业大学环境与能源工程学院,北京100124

出　　处：《华南师范大学学报（自然科学版）》2017年第5期47-52,共6页Journal of South China Normal University(Natural Science Edition)

基　　金：广东省高层次人才项目(9010-14193);河北省青年拔尖人才计划

摘　　要：在CCSD(T)/cc-p VTZ水平下,对X…Y(X=Li F、NH_3、H_2O;Y=HF、Li F)复合物的9个结构进行几何构型优化和红外振动频率计算.根据定域化分子轨道、原子自然电荷、Wiberg键级的分析表明HFLi F分子中的H—F键是共价键,而Li—F键则为离子键而非共价键.H3N…Y(Y=HF、Li F)、H_2O…Y(Y=HF、Li F)中的氢键或锂键源于静电相互作用,并非共用电子的共价键.结合能的计算表明:与HF相比,Li F与X(X=Li F、H_2O、NH_3)的结合能更高;结合能从高到低依次为Li F>NH_3>H_2O.红外振动频率分析表明HF与NH_3、H_2O形成红移氢键,即H—F键长增加,相应的H—F伸缩振动频率降低.H3N…Li F的Li—F键键长增加同时伸缩振动频率减少.而Li F与H_2O形成锂键后,键长增加0.001 6 nm,而Li—F的伸缩振动频率反而增加了2 cm-1,即蓝移锂键.Nine structures of X…Y(X = LiF,NH_3,H_2O; Y = HF,LiF) complexes were optimized at CCSD(T)/ccp VTZ level. The results of natural atomic charges,Wiberg bond index and localized molecular orbitals suggest that H—F bond in HFLiF is covalent,but Li—F bond is more like ionic instead of covalent. The bind energy of LiF with X(X = LiF,H_2O,NH_3) is higher than that of X…HF. The order of bind energy is LiF…Y> H3 N…Y > H_2O…Y(Y = LiF,HF). The obtained vibrational frequencies of H—F bond in H3 N …HF or H_2O …HF decrease while H—F bond length increase,suggesting a red-shifting hydrogen bond. The red-shifting lithium bond is also found in H3 N…LiF. In H_2O…LiF,it is found that Li—F bond elongated 0. 001 6 nm while the stretch vibrational frequency of Li—F increased 2 cm-1. Thus,the lithium bond in H_2O…LiF should be considered as blue-shifting lithium bond.

关 键 词：X…Y(X=LiF NH3 H2O Y=HF LiF)复合物 蓝移锂键 氢键 定域化分子轨道 

分 类 号：O43[机械工程—光学工程]