Extending the Family of Tetrahedral Tectons: Phenyl Embraces in Supramolecular Polymers of Tetraphenylmethane-based Tetraphosphonic Acid Templated by Organic Bases

A missing member of the tetraphenylmethane-based
family of supramolecular
tectons, tetrakis­(4-phosphonophenyl)­methane, TPPM (1),
has been obtained, characterized, and reacted with organic amines
that possess modulated conformational flexibility. The obtained adducts
serve as a diverse platform for the investigation of the amine templating
effect on phenyl embraces, the resulting supramolecular network, and
its topology. Hirshfeld surface (HS) analysis has been employed for
the investigation of phenyl embraces, which led to the indication
of characteristic HS features of 4PE and 6PE phenyl embraces. One
can also observe a new subtype of phenyl embrace, namely, HBA-PE (hydrogen
bond-assisted phenyl embrace), which constitutes the cooperation of
two interactions: strong hydrogen bonding and a phenyl embrace. A
topological insight into TPPM hydrogen-bonded networks is also provided.
As a result, we found a connection of the amine template type with
the periodicity of the underlying supramolecular network. Additionally,
we report three previously unknown topologies. The obtainment of an
unusual example of a phosphonic acid cocrystal with base (adduct 3) allowed for the determination of specific 2D fingerprint
plot patterns for acid–base structures, with and without proton
transfer.