Solid State Assemblies of Cyclic Imides Tethered Hydroxy Benzoic Acids with Pyridine and Quinoline: Toward the Formation of Channels and Cavities

A series of inclusion compounds of different cyclic imides
tethered hydroxy-benzoic acid hosts (1–8) with guests pyridine (I–IV) and
quinoline (V–X) have been prepared
and structurally characterized. Supramolecular aspects pertaining
to the influence of guest molecules toward the formation of solid
state network structures of hosts are described. Hydrogen bonding
of both carboxylic acid and hydroxyl groups as well as π···π
stacking of aromatic imide units led to the formation of channels
of different dimensionalities in the supramolecular architectures
of I–X. In these structures, the
channels are occupied by the guest molecules that interact with both
hydrogen bonding groups of host molecules via different types of hydrogen
bond motifs. Thermogravimetric analyses correspond to the association
of different numbers of guest pyridine or quinoline molecules with
isomeric hydroxy-benzoic acid hosts. Solid state fluorescence spectra
of hosts 1–8 are recorded which show
emissions in the region of 412–516 nm. Overall this structural
study represents the combined effects of π-stacking aromatic
imide synthons and two hydrogen bonding carboxylic acid and hydroxyl
functional groups in the presence of aromatic nitrogen containing
guests to create fascinating supramolecular architectures.