Mechanistic Studies towards the formation of Isowurtzitane Cages

The design and synthesis of energetic materials is crucial for the development of new propellants and explosives that have better performance, lower sensitivities, and higher thermal stabilities. Currently, three-dimensional “cage”-energetics are being targeted as superior explosives due their larger densities and heats of formation. Energetic cage explosives derived from isowurtzitane are currently the highest performing explosives known. However, the chemical process by which the 3D-cage forms isn’t known or is poorly understood. Several mechanistic proposals have been suggested, but little evidence exists supporting these hypotheses. This discussion will focus on our attempts to deduce the reaction mechanisms for isowurtzitane cage formation using modern synthetic, analytical, and computational techniques. We have recently studied the reactions of benzylamine with glyoxal derivatives and have observed several reaction intermediates via in situ NMR analyses and through chromatographic methods coupled with mass spectrometry. These observed intermediates have allowed us to computationally probe the reaction mechanism providing evidence for transient intermediates that are too reactive to observe. These techniques have allowed us to generate an evidence-based reaction mechanism for the formation of isowurtzitane derived energetic materials.