Binding of fluorine containing anions by new cationic Co(III) complex: Competitive interaction of chloride and hexafluorophosphate with [Co(phen)(H 2biim) 2] 3+

Abstract

A new mixed ligand cobalt(III) complex salt [Co(phen)(H 2biim) 2]Cl 3 ( 1) (where phen = 1,10-phenanthroline, H 2biim = 2,2′-biimidazole) has been synthesized for the first time. In an effort to explore this new cationic complex [Co(phen)(H 2biim) 2] 3+ as binding agent for fluoroanions, complex salt [Co(phen)(H 2biim) 2](PF 6) 2Cl·2H 2O( 2) has been synthesized and characterized. Single crystal X-ray structure determination has revealed that complex salt 2 crystallizes in monoclinic crystal system with space group P2 1/ c and consist of one complex cation, one chloride, two hexafluorophosphate anions and two water molecules of crystallization. The packing analyses revealed that the complex cations are arranged in such a way that N–H groups of biimidazole moiety are involved in N–H⋯Cl interaction with chloride ion while C–H groups of phen/H 2biim are involved in C–H⋯F interaction with hexafluorophosphate to keep these groups in close proximity. A strong network of hydrogen bond interactions C–H⋯F, N–H⋯O, N–H⋯Cl, C–H⋯O (water) and O–H⋯O (water) are responsible for the stabilization of 3D supramolecular architecture. To the best of our knowledge, this is the first crystal structure of any salt containing the cation [Co(phen)(H 2biim) 2] 3+.