Synthesis, crystal structure, and third-order NLO properties of a new supramolecular cocrystals of 18-crown-6 with 5-amino-2,4,6-triiodoisophthalic acid

A self-assembled supramolecular cocrystals of (18-crown-6)0.2(5-amino-2,4,6-triiodoisophthalic acid)0.2(H2O) (C12H24O6.2(C8H4I3NO4)0.2(H2O)) have been synthesised from 18-crown-6 (18C6) and 5-amino-2,4,6-triiodoisophthalic acid (5ATIPA) by slow evaporation method. The crystal structure was elucidated by the single crystal X-ray diffraction analysis, and it belongs to a monoclinic system with a centric space group P2(1/C). Crystal cohesion is facilitated by the existence of intramolecular (N-H center dot center dot center dot I) and intermolecular (O-H center dot center dot center dot O, C-H center dot center dot center dot O) contacts. All of the oxygen atoms in 18C6 interact with the water molecule via bifurcate hydrogen bonds. The FT-IR analysis identifies the distinctive vibrational patterns. The direct band gap energy is estimated as 3.13 eV by Kubelka-Munk algorithm. Through Hirshfeld surface analysis, fingerprint plots are used to locate and quantify the hydrogen bonding interactions between and within molecules. The third-order nonlinear optical susceptibility (chi((3))) of the grown crystal is 5.98x10(-6) esu. The good third-order NLO responses indicate that the title compound qualifies as a good optical material for photonics devices, optical switches, and optical power limiting applications.