The syntheses and crystal structures of Cs 2[Co 2(nta) 2(μ-OH) 2] · 4H 2O and (C 10H 10N 3) 2[CoCl 4

Abstract

The crystal structure of Cs 2[Co 2(nta) 2(μ-OH) 2] · 4H 2O (nta = nitrilotriacetate) has been determined from three-dimensional X-ray diffraction data. Two hydroxo groups act as bridging groups between the two Co metal centres. The CoOH bond distances are 1.899(5) and 1.897(5) Å, respectively and the CoOHCo bond angles 98.2(2)°. The nta ligand acts as a tetradentate ligand and bonds with a nitrogen as well as three oxygen atoms to the Co metal centre. The CoN and CoO (av) bonds are 1.922(6) and 1.895(5) Å, respectively. (C 10H 10H 3) 2[CoCl 4] consists of discrete monoprotonated 2,2′-iminodipyridinium cations and CoCl 4 2− anions. The anions assume a regular tetrahedral geometry, with the ClCoCl bond angles varying between 107.34(10) and 112.07(10)°. The CoCl bond distances are 2.270(2) and 2.282(2) Å, respectively. The two pyridine rings in the cation assume an almost planar orientation with a derivation of 7.7(6)° for the dihedral angle between the two ring systems. The planar orientation can be attributed to weak hydrogen bonding between the unprotonated nitrogen atom of the one pyridine ring and the proton bonded to the other nitrogen atom on the adjacent ring.