Crystal Structure of cis-Bis(2,2′-bipyridyl)dichlorocobalt(III) Nitrate Methanol Solvate (original) (raw)

X-ray Structure Analysis Online

The coordination chemistry of cobalt(III) has been investigated because of their redox and magnetic properties. On the basis of these properties, recently there are many reports concerning cobalt(III) complexes for applications in biology, medicine, and photocatalists. 1,2 Especially cobalt(III) complexes with two polypyridyl ligands at the cis-position of each other, such as cis-[CoCl2(N-N)2] + or cis-[Co(CO3)(N-N)2] + (N-N = 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) etc.), have been prepared. These are not only used as starting materials for many functional complexes, 4,5 but also the cis-bis(N-N)cobalt(III) complexes have been investigated concerning their chemical and biological properties. 6 In 2016, the crystal structure and anticancer activity of cis-[CoCl2(bpy)2](NO3)·2H2O were reported by Das and co-workers. The structure parameters of a cation part were similar to those of the previously reported crystal structure, [CoCl2(bpy)2]Cl·2H2O. 7 Das and co-workers focused on 1-D water-anion chains, which were ladder-shape hydrogen bonding networks between counter ions, NO3 -, and square units of four lattice water molecules connected by hydrogen bonding interactions, in the crystal, because polypyridyl moieties that were present in biological molecules might stabilize various water topologies in the environment, resembling those in living system. They concluded that the water-nitrate cluster might bring to light, yet different novel, mode of cooperative association of water molecules with nitrate anions. It brought about an efficient cleavage of double-stranded DNA without the requirement of an external agent in a concentration-dependent manner. 6 Similar 1-D water-anion chains were also observed in the Cl-salt, 7 though it is not described in this report. These crystal structures of cis-[CoCl2(bpy)2](X)·2H2O (X = Clor NO3 -) 6,7 indicated that a complex cation, cis-[CoCl2(bpy)2] + , would have two kinds of 1-D chains in the crystal without depending on a kind of counter ion. Herein, we report on the crystal structure of cis-[CoCl2(bpy)2](NO3)·CH3OH , and compare it with cis-[CoCl2(bpy)2](X)·2H2O (X = Clor NO3 -) 6,7 to find the feature of the cis-[CoCl2(bpy)2] + complex in the crystal. In the result, we found that the cationic part in this complex was also similar to those in two previously reported complexes, although this crystal had no 1-D water-anion chains. We particularly describe the relationship among cation complexes, NO3anions, and methanol molecules in the crystal.