1,4-Diazacubane crystal structure rectified as piperazinium

Abstract

All 21 [n]-azacubanes are proposed by theoreticians to be stable, however, to-date only the synthesis of 1,4-diazacubane has been reported – as a Ni²⁺ templated Kagome metal organic framework (MOF). Described herein is the structural reassignment of this Kagome MOF on the basis of deducing the precise experimental procedure, and demonstrating that rather than the formation of 1,4-diazacubane, charge is balanced by disordered piperazinium cations across a twelve-fold symmetry site. Furthermore, quantum chemical calculations reveal that 1,4-diazacubane is unlikely to form under the reported conditions due to unfavorable enthalpies for select hypothetical reactions leading to such a product. This significant structure correction upholds the unconquered synthesis status quo of azacubane.