Solvent-Induced Manipulation of Supramolecular Organic Frameworks

Supramolecular organic frameworks
based on C-alkylresorcin­[4]­arenes
(RsCn) and the conformationally flexible spacer 1,2-bis­(4-pyridyl)­ethane
(bpea) are discussed here. The conformational flexibility of bpea
was predetermined with the help of electronic structure calculations
of bpea in the gas and solution phases. The architectures of these
frameworks are primarily governed by O–H···O
and O–H···N intermolecular hydrogen-bonding
interactions between the components of the frameworks. The unique
arrangement of the bpea spacer around RsCn yields
continuous 1D wavelike and 1D lateral hydrogen-bonded frameworks.
The cocrystals of RsCn with bpea show conformational
variation as a function of a change in the solvent of crystallization.
In acetonitrile, the bpea spacer exists in the trans form, whereas in ethanol it adopts both gauche and
trans forms. RsCn, on the other hand, adopts a pinched-cone
conformation in both solvents. The extended frameworks of RsCn–bpea in ethanol enclose continuous channels filled
with arrays of hydrogen-bonded gauche-bpea molecules.