Synthesis, characterization and X-ray structure of trans-[(nitro)bis(ethylenediamine)( p-nitrobenzoato) cobalt(III)] [p-nitrobenzoate·p-nitrobenzoic acid]

Abstract

The complex salt trans-bis(ethylenediamine)dinitrocobalt(III) nitrate reacts with p-nitrobenzoic acid in a mixture of water and ethanol to give orange crystals of the novel salt trans-[(nitro) bis(ethylenediamine)( p-nitrobenzoato)cobalt(III)][p-nitrobenzoate·p-nitrobenzoic acid], [Co(en)₂(NO₂)(4-NO₂C₆H₄CO₂)][4-NO₂C₆H₄CO₂)·4-NO₂C₆H₄CO₂H]. It has been characterized by elemental analysis, spectroscopic techniques and its structure has been determined by single crystal X-ray diffraction methods. The salt is triclinic, space group P with a = 9.5061(9), b = 9.6367(8), c = 16.2781(14) Å, α = 91.66(1), β = 92.91(1), γ = 105.03(1)°, Z = 2, V = 1437.0(2) ų. The complex consists of trans-[Co(en)₂NO₂(4-NO₂C₆H₄CO₂)]⁺ cations and hydrogen bonded [4-NO₂C₆H₄CO₂·4-NO₂C₆H₄CO₂H]^– anions. The structure is stabilized by additional hydrogen bonds between cations and anions resulting in a unique acid salt containing the cation trans-[Co(en)₂NO₂(4-NO₂C₆H₄CO₂)]⁺.

Keywords:

• Cobalt(III)
• 4-Nitrobenzoate
• 1,2-Diaminoethane
• X-ray structure
• Spectroscopy
• Hydrogen bonding

Acknowledgements

The authors gratefully acknowledge the financial support of UGC vide grant no. F.12-38/2003(SR). They also thank Prof. Dr H. Nöth for the generous allocation of diffractometer time.