Cationic metal complex, carbonatobis(1,10-phenanthroline)cobalt(III) as anion receptor: Synthesis, characterization, single crystal X-ray structure and packing analysis of [Co(phen)2CO3](3,5-dinitrobenzoate)•5H2O

To explore the potential of [Co(phen)(2)CO3](+) as anion receptor, red coloured single crystals of [Co(phen)(2)CO3](dnb)center dot 5H(2)O (dnb = 3,5-dinitrobenzoate) were obtained by recrystallizing the red microcrystalline product synthesised by the reaction of carbonatobis (1,10-phenanthroline)cobalt(III)chloride with sodium salt of 3,5-dinitrobenzoic acid in aqueous medium (1:1 molar ratio). The newly synthesized complex salt has been characterized by elemental analysis, spectroscopic studies (IR. UV/visible, H-1 and C-13 NMR), solubility and conductance measurements. The complex salt crystallizes in the triclinic crystal system with space group P (1) over bar. having the cell dimensions a = 10.3140(8), b = 12.2885(11), c = 12,8747(13), alpha = 82.095(4), beta = 85.617(4), gamma = 79.221(4)degrees, V = 1585.6(2) angstrom(3), Z = 2. Single crystal X-ray structure determination revealed ionic structure consisting of cationic carbonatobis(1,10-phenanthroline)cobalt(III), dnb anion and five lattice water molecule. In the complex cation [Co(phen)(2)CO3](+), the cobalt(III) is bonded to four nitrogen atoms, originating from two phenanthroline ligands and two oxygen atoms from the bidentate carbonato group showing an octahedral geometry around cobalt(III) center. Supramolecular networks between ionic groups [CHphen- center dot center dot center dot X-anion(-)] by second sphere coordination i.e. C-H center dot center dot center dot O (benzoate), C-H center dot center dot center dot O (nitro), C-H center dot center dot center dot O (water) besides electrostatic forces of attraction alongwith pi-pi: interactions stabilize the crystal lattice. (C) 2009 Elsevier B.V. All rights reserved.