1,4-Benzenedisulfonic acid (H2BDS) as terephthalic acid analogue for the preparation of coordination polymers: the examples of M(BDS)(NMP)3 (M = Mn, Fe, Co; NMP = N-methylpyrrolidone)

Abstract

The solvothermal reactions of 1,4-benzenedisulfonic acid, H₂BDS, with suitable salts of manganese, iron, and cobalt led to the new disulfonates M(BDS)(NMP)₃ (M = Mn, Fe, Co), when N-methylpyrrolidone (NMP) was used as the solvent. The isotypic compounds crystallize with triclinic symmetry (P, Z = 2; M = Mn: a = 916.84(3) pm, b = 965.57(3) pm, c = 1437.87(5) pm, α = 95.297(2)°, β = 97.834(2)°, γ = 92.576(2)°, R₁/wR₂(I₀ > 2σ(I₀)) = 0.0300/0.0701; M = Fe: a = 911.98(5) pm, b = 960.75(5) pm, c = 1432.41(8) pm, α = 94.951(2)°, β = 98.050(3)°, γ = 92.029(2)°, R₁/wR₂(I₀ > 2σ(I₀)) = 0.0238/0.0689; M = Co: a = 911.3(1) pm, b = 959.5(1) pm, c = 1428.6(2) pm, α = 94.791(5)°, β = 98.229(5)°, γ = 91.873(6)°, R₁/wR₂(I₀ > 2σ(I₀)) = 0.0264/0.0684). In the crystal structure, the M²⁺ ions (Mn²⁺, Fe²⁺ and Co²⁺) are in octahedral oxygen coordination of three monodentate disulfonate groups and three NMP molecules. The disulfonate groups link the metal ions into infinite layers. Thermoanalytical investigations showed that the desolvation of the compounds occurred in a temperature range between 50 °C and 330 °C. The solvent free sulfonates showed remarkable high stabilities up to nearly 500 °C. The thermal behaviour was investigated by DSC/TG measurements and X-ray powder diffraction.