Conspectus
Reticular chemistry has provided
intriguing opportunities for systematically
designing porous materials with different pores by adjusting the building
blocks. Among them, framework materials have demonstrated outstanding
performance for the design of new functional materials used in a broad
range of fields, including energetic materials. Energetic materials
are widely used for rockets, satellites, mining, and tunneling. In
terms of energetic materials, explosophores and nitrogen-rich heterocycles
are fundamental building blocks for high-energy compounds. However,
the traditional strategy of synthesizing HEDMs (high energy density
materials) at the molecular level has faced the long-term challenge
of balancing energy and stability. Inspired by reticular chemistry,
nitrogen-rich heterocycles offer diverse nitrogen sites for designing
diversified coordination interactions. Ionic bond interactions exist
in a wide range of energetic salts. Furthermore, most metastable explosophores,
e.g., nitro, nitramino, and amino groups, can form strong hydrogen-bonding
networks. Based on these noncovalent interactions (such as coordination,
ionic, and/or hydrogen bonds (HBs)) and/or covalent interactions can
determine intermolecular packing/linkage of the energetic fuel and
oxidizer components, reticular chemistry provides a new platform evolving
from single-molecular design to various energetic frameworks (E of
the energetic frameworks with superior comprehensive properties. For
example, to achieve coordination with metals or introduce sufficient
hydrogen bond donor/acceptor structural units, the host structure
of energetic framework materials usually contains less oxygen-rich
substituents such as nitro, so the host molecules of the framework,
F) at the crystal level, which can enhance the integrated stabilities
of EFs.
Along with growing concerns about the environment and
safety issues,
considerable effort has been devoted to pursuing environmentally friendly
and insensitive energetic materials. The newly emerging EFs are conducive
to introducing explosophores into a green chemical pathway. Benefiting
from these cross-disciplinary achievements, taming metastable energetic
molecules in specific porous frameworks is a green strategy to desensitize
energetic materials while concomitantly retaining excellent energetic
properties, which has become one of the most forward and promising
investigations. In the past decade, EFs have achieved further results
in stabilizing and greening energetic materials using HBs, covalent
bonds, and alkaline earth metal-involving coordination bonds to avoid
heavy metal toxicity and to employ halogen-free oxidizers. Because
this field is still expanding rapidly, it is of great value for researchers
and possible users of the work to be able to view all the progress.
Through this Account, we intend that more readers will become knowledgeable
about EFs, including their definition, history, synthesis, properties,
and possible applications. The aim of this Account is to present the
latest advances...
