Binary azides of p-block elements1 (E(N3)n, E = Si-Pb, Al or P, n = 2, 3, 4 or 5) are fascinating precursors for the synthesis of nitrogen-rich coordination compounds. However, the combination of high nitrogen content and a comparably high degree of covalence of the element-nitrogen bond render these azides to be highly endothermic and kinetically instable. The coordination of N-heterocycles increase stability dramatically and allows the isolation and full characterisation of these azides as well-defined hypercoordinate complexes bearing pyridine-type- (A1,2)2 and carbene ligands (A3,4) (scheme). These species possess intriguing reactivity which was demonstrated in reactions leading to unusual hypervalent complexes in which the binary azide is released (i), with nitriles causing multiple 1,3-cycloadditions to form unusual hexacoordinate polytetrazolate complexes (B) (ii),3 with strong bases leading to non-classical carbene complexes (C) and under elimination of dinitrogen to form imidazolideneimido complexes (E).4 We have demonstrated that azido ligands in homoleptic p-block complexes can be replaced completely by kinetically more stable, nitrogen-rich tetrazolato ligands resulting in species of the type E(N4CH)3- and E(N4CH)62- (D).4 Syntheses, reactivity, structures, and thermal and spectroscopic properties of the new species will be described.

Taming binary p-block azides with N-heterocyclic σ-donors as precursors for the formation of nitrogen-rich tetrazolato complexes

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.