Synthesis and characterization of ethylenediaminium nitrophenolate

A series of organic salts based on ethylenediaminium divalent cation, [C₂H₁₀N₂]X₂ (where X = 2-nitrophenolate (1), 3-nitrophenolate (2), 4-nitrophenolate (3), 2,4-dinitrophenolate (4), 2,6-dinitrophenolate (5) and 2,4,6-trinitrophenolate (6) respectively) have been prepared. Their structures were characterized and confirmed by ¹H and ¹³C NMR spectroscopy, IR spectroscopy, elemental analysis and ESI-MS. Additionally, crystal structures of compounds 2-nitrophenolate and 4-nitrophenolate were determined with X-ray single crystal diffraction. Complex salt 1 crystallizes in the orthorhombic Pccn space group with unit cell parameters: a = 26.047(5) Å, b = 6.8351(14) Å, c = 8.4637(17) Å, V = 1506.8 ų, Z = 4. Complex salt 3 crystallizes in the monoclinic C2/c space group with additional one free water molecule being included. Its unit cell parameters are a = 11.328(2) Å, b = 7.2623(15) Å, c = 20.038(4) Å, β = 93.58(3)°, V = 1615.2(6) ų, Z = 4. Compounds 1 and 3 have strong 3D hydrogen-bonded network, which play a major role in stabilizing the crystal lattice. Distinct cationic and anionic layers can also be seen in the (0 1 0) plane. The IR and Raman spectra of 2-nitrophenolate and 4-nitrophenolate were interpreted and the assignments of bands to the corresponding vibrations were proposed based on the data calculated by the B3LYP/6-311G(d, p) level. Finally, the influence of molecular structure on both the densities and thermal stabilities of synthesized compounds have been discussed.