Heterocyclic Salt Synthesis and Rational Properties Tailoring
Treść / Zawartość
Chemical structure determines the inherent properties displayed by a given compound, and these properties, in turn, produce a specifc performance behavior. Rationally designing chemical structure to predictably modify compound properties, such that performance behavior can be tailored in a controlled manner, defnes the objective of a pertinent synthesis effort. Achieving this objective by introducing structural alterations in a neutral covalent compound offers only one approach for resultant properties modifcation. Heterocyclic salts signifcantly enhance the fexibility for achieving properties modifcation via three strategic approaches: (1) compositionally pairing various cation structural classes with a number of anion structural classes, (2) systematically altering the structure of the cation; and, (3) systematically altering the structure of the anion. To illustrate this premise, four general synthesis methods to synthesize heterocyclic salts, including several new binary heterocyclium icosahedral closo-borane and closo- carborane salts, frst are outlined. Secondly, properties modifcation approaches of neutral covalent compounds are then compared with those approaches available for various heterocyclic salts. Lastly, a key example, using three unsaturated bridged heterocyclium di-cation salts, demonstrates how rational structure design, and its effect on resultant predictable properties modifcation, produces tailored performance behavior to reach the thermochemical initiation threshold needed for combustion. This is achieved with predictable properties modifcations that increase salt energy content, or that accelerate the reaction kinetics of the thermochemical initiation process.
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