Role of weak interactions in binding of aryldicarboxylate ion: Synthesis, spectroscopic characterization, single-crystal X-ray structure determination and packing analysis of [Co(phen)2CO3]2(C8H4O4)·15H2O

To explore the role of weak interactions in aryldicarboxylate binding, the hydrated complex salt, [Co(phen)2CO3]2(C8H4O4)·15H2O, 1, (C8H4O42-=terephthalate) was synthesized and characterized by elemental analyses, spectroscopic studies (IR, UV/Visible, 1H, 13C and 59Co NMR), physical measurements and single-crystal diffraction. Compound 1 crystallizes in space group P1¯ and the unit cell contains two complex cations, one terephthalate anion and fifteen water molecules. Two N,N-bidentate 1,10-phenanthroline ligands and one O,O-bidentate carbonate dianion lead to a distorted cis-CoO2N4 octahedral geometry for the metal ion. In the crystal, a supramolecular network built up from CH⋯Owater/carboxylate (through second sphere interactions) and OH⋯Owater/carboxylate, π–π stacking and CH⋯π interactions besides electrostatic forces of attraction help to consolidate the packing. Interestingly a chain of water hexamers and tetramers running along the a-axis also have been observed which is trapped in between the complex cations and terephthalate anions framework.