|The combined US navy, US Air Force and the US Defense Threat Reduction Agency were more than happy to fund research into the adduct of sodium borohydride and nitroform as a new high-energy density material aka explosive. The report is titled "BH3C(NO2)3: The First Room-Temperature Stable|
(Trinitromethyl)borate" and principal author Bélanger-Chabot points out that the compound is not only explosive but also green because the boron employed is non-toxic (DOI). As if greenness is relevant in warfare. Additional and more sensible rationale, a stable B-C bond in this compound is certain to stabilise an otherwise unstable nitroformate anion. In the meanwhile the initial recipe is dead-simple , mix nitroform and sodium borohydride in glyme and after effervescence the yellow solution contains a quantitative amount of BH3C(NO2)3. The work-up is tricky : The solvent was removed under vacuum between -40 and -8°C over the course of several days. The compound exists thanks to the glyme, remove it by a vacuum and you end up with sodium nitroformate. Even with glyme decomposition takes place within a week at RT.
So the compound is less stable than expected, and the authors suggest that the strong B-C bond is partially offset by reorganisations from planar to tetrahedral on dissociation of the two ionic fragments.
Questions: why is the adduct called a borate when no oxygen is in sight? With respect to the opening line : "Ever since the first report on the nitroformate anion (...) trinitromethyl derivatives have been a subject of significant interest" what is the meaning of "signification interest" given that this first report dates back to 1899, more than a century ago. I guess interest in the electron or radioactivity can be considered "significant" in this timespan but the nitroformate anion?