摘要
采用量子化学计算和分子动力学(MD)模拟,研究了溶剂化物环四亚甲基四硝胺(HMX)/N,N-二甲基甲酰胺(DMF)的结构和分子间相互作用。对浸渍在DMF溶剂中的β-HMX分子的MD模拟表明,HMX的分子构象已经从β转变为α相。在M P2/6-31G*水平上的理论计算也说明,在D M F溶剂中,α-HM X比β-HM X更稳定。这解释了在HM X/D M F溶剂化物的多晶型中,所有的HMX分子均呈α构象的原因。采用MP2/6-31G*方法,对α-HMX和DMF分子间可能的同型和异型二聚体进行结构优化。结果表明,组分间存在C—H…O氢键相互作用,并且α-HMX/DMF的稳定化能非常接近α-HMX/α-HMX,并远远大于D M F二聚体的。这意味着异型分子间力可和同型分子间力竞争。从热力学的观点来看,共结晶过程可能发生。对α-HM X在D M F中的过饱和溶液的M D模拟表明,分子间相互作用对共结晶有利。这些理论研究对理解在HM X的D M F溶液中为什么发生的是共结晶而不是重结晶提供了有价值的信息。
The structures and intermolecular interactions for octahydro-1 , 3, 5, 7-tetranitro-1 , 3, 5, 7-tetrazocine （HMX）/N, N-dimethylformamide （DMF） solvate have been investigated through quantum chemistry calculations and molecular dynamics （MD） simulations. MD simulation for a /3-HMX molecule immersed in DMF solvent shows that/3 conformation has been transformed into ~ form. Theoretical calculations at the MP2/6-31 G ＊ level also indicate that the α-HMX is more stable than/3-HMX in DMF solution. This explains why all HMX molecules present α-form in the polymorphic forms of HMX/DMF solvate. Geometrical optimizations at the level of MP2/6-31 G＊ are performed for all the possible homodimers and heterodimers between α-HMX and DMF. Results reveal that C-H ... O hydrogen bond interactions exist between components. Moreover, the stabilization energy of α-HMX/DMF is very close to that of α-HMX/α-HMX and much larger than that of DMF dimer. This means that the heteromeric intermolecular forces can compete with the homomeric intermolecular forces, and co-crystallization is possible to occur from the thermodynamics viewpoint. MD simulation for the supersaturation solution of α-HMX in DMF presents the intermolecular interactions is in favor of co-crystallization. These theoretical investigations provide valuable information for understanding why there occurs co-crystallization other than re-crystallization in DMF solution of HMX.
出处
《含能材料》
EI
CAS
CSCD
北大核心
2012年第4期454-458,共5页
Chinese Journal of Energetic Materials
基金
National Natural Science Foundation of C hina(NSAF,No.11176029)
the Key Research Project of Education Department of SichuanProvince(No.10zd1106)
关键词
物理化学
HMX
构象
稳定化能
C-H…O氢键
共结晶
physical chemistry
conformation
stabilization energy
C-H...O hydrogen bond
co-crystallization
