Synthesis, spectroscopic and X-ray structure characterization of ethylenediammonium chromate and ethylenediammonium dichromate

Abstract

The reaction of ethylenediammonium chloride (enH2)Cl2 with potassium chromate or dichromate in a 1:1 mole ratio results in the formation of the title complexes ethylenediammonium chromate (enH2)[CrO4] 1 and ethylenediammonium dichromate (enH2) [Cr2O7] 2 in good yields. The two complexes have been characterized by IR, UV-Vis, 1H NMR spectroscopy and metal analysis and their structures have been determined by single crystal X-ray crystallography.Ethylenediammonium chromate 1 crystallizes in the orthorhombic space group P212121 (IT-Nr. :19) with the unit cell dimensions a = 6.656(1)Angstrom, b = 8.869(1) Angstrom, c = 11.831 (2)Angstrom, V = 698.4(2) Angstrom3, Z = 4. The structure of 1 consists of tetrahedral tetraoxochromate dianions, with the Cr at the center of the tetrahedron. Ethy lenediammonium dichromate 2 crystallizes in the monoclinic space group C2/c (IT-Nr. :15) with the unit cell dimensions a = 13.464(2) Angstrom, b = 7.791(1)Angstrom, c = 8.639(1)Angstrom, Beta= 108.97(1), V = 857.0(2) Angstrom3, Z = 4. In both the compounds, short H-bonding contacts are observed between the oxygen atoms bound to the Cr containing dianion and the H attached to the N atom of the organic dication.