Artificial molecular
machines have captured the full attention
of the scientific community since Jean-Pierre Sauvage, Fraser Stoddart,
and Ben Feringa were awarded the 2016 Nobel Prize in Chemistry. The
past and current developments in molecular machinery (rotaxanes, rotors,
and switches) primarily rely on organic-based compounds as molecular
building blocks for their assembly and future development. In contrast,
the main group chemical space has not been traditionally part of the
molecular machine domain. The oxidation states and valency ranges
within the p-block provide a tremendous wealth of structures with
various chemical properties. Such chemical diversity—when implemented
in molecular machines—could become a transformative force in
the field. Within this context, we have rationally designed a series
of NH-bridged acyclic dimeric cyclodiphosphazane species, [(μ-NH){PE(μ-NtBu)2PE(NHtBu)}2] (E = O and
S), bis-PV2N2, displaying bimodal
bifurcated R21(8) and trifurcated R31(8,8) hydrogen bonding motifs. The reported species reversibly
switch their topological arrangement in the presence and absence of
anions. Our results underscore these species as versatile building
blocks for molecular machines and switches, as well as supramolecular
chemistry and crystal engineering based on cyclophosphazane frameworks.