Engineering Void Space Enclosed within Resorcin[4]arene-Based Supramolecular Frameworks

A family
of hydrogen-bonded supramolecular frameworks based on C-alkylresorcinol­[4]­arene (RsC) and 4,4′-bipyridine
(bpy) type spacers are described in this article. The size and shape
of the void space enclosed within these frameworks are engineered
by varying the type of solvent (acetonitrile and ethanol), spacer
molecules (4,4′-bipyridine (bpy), trans-1,2-bis­(4-pyridyl)­ethylene
(bpe), 1,2-bis­(4-pyridyl)­acetylene (bpa)), and the conformations and/or
type of RsC bowl (boat vs cone or C-methylresorcin­[4]­arene/RsC1
vs C-propylresorcin­[4]­arene/RsC3). A change in the
solvent system from acetonitrile to ethanol brings about a conformational
change with the RsC1 macrocycle and also results in the distinct orientation
of spacer molecules around the RsC macrocycle. The predominant feature
in all of the frameworks is the O–H···N intermolecular
interaction between RsC building blocks and bipyridine-type spacers.
The resultant solvent-filled void spaces available within frameworks
can be controlled by manipulating the parameters investigated in this
study.