Caged structures as energetic materials

The sensitivity of an explosive to impact and friction is a key factor in deciding whether it finds practical use. Most developed countries have an ongoing program to gradually replace current explosives and propellants with insensitive materials, a process which will greatly reduce the risk of accidental detonation. At present these programs are still in their early phases. 

The weakest bonds in an explosive will often determine its sensitivity to impact and such bonds are usually present in the explosophoric groups. Steric and electronic factors also play an important role. Unsurprisingly, factors which increase explosive performance usually have a detrimental effect on stability and sensitivity, and so a compromise must be made. As the database of energetic materials and their properties is ever increasing this task becomes 

Organic Chemistry of Explosives 2007 John Wiley Sons, Ltd. 

Preliminary evaluations of polynitropolycyclic compounds reveal that this class of energetic materials is relatively powerful and shock insensitive, and so, well suited for use in future explosive and propellant formulations. 

Energetic materials with strained or caged structures are often much more difficult to synthesize compared to their open chain counterparts. This presents a further challenge to researchers of new energetic materials - while new compounds can be synthesized on a laboratory scale, and their properties and performance tested, the complexity of the synthetic routes may render their use as explosives nonfeasible. This particularly applies to polynitropolycyclic hydrocarbons because the direct nitration of these hydrocarbons is not a feasible route of introducing nitro groups without considerable decomposition. 

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