Designed synthesis, structure, and 3-D topology of a supramolecular dimer and inorganic–organic cocrystal

Abstract

Synthesis and structure of a supramolecular dimer and inorganic–organic cocrystal of composition [{Cu^IIL¹⊂(H₂O)}₂(C₈H₆O₄)] (1) are described (H₂L¹= N,N′-ethylenebis(3-ethoxysalicylaldimine); C₈H₆O₄ = terephthalic acid). Crystal engineering has been utilized for the designed synthesis of the title compound. Compound 1 crystallizes in a triclinic system with P 1 space group. The structure consists of terephthalic acid and two symmetry related inclusion products [Cu^IIL¹⊂(H₂O)], in which the water molecule is encapsulated in the O₄ compartment by forming bifurcated hydrogen bonds involving two hydrogen of water and phenolate and ethoxy oxygens of the compartmental ligand. Hydrogen bonding between encapsulated water molecules and terephthalic acid forms the supramolecular dimer. The title compound is an example of an inorganic–organic cocrystal as well. Weak interactions, such as semicoordination of phenoxo oxygen of one unit to the metal center of a symmetry related unit and C–H ··· O, and O–H ··· O hydrogen bonds result in generation of an overall 3-D topology in the title compound. The 3-D topology can be understood as interlinking of two different 2-D sheets.

Keywords:

• Supramolecular
• Inorganic–organic cocrystal
• Terephthalic acid
• 3-D
• Inclusion compound

Acknowledgments

Financial support from the Department of Science and Technology, the Government of India (SR/S1/IC-12/2008), Council for Scientific and Industrial Research (Fellowship to S. Hazra) and University Grant Commission (Fellowship to S. Sasmal and S. Sarkar) are acknowledged.