Synthesis, characterization and crystal structures of two alkaline-earth metal complexes of olsalazine

Abstract

Two one-dimensional linear coordination polymers, [Mg(L) · 4(H₂O)] (H₂L = olsalazine) and 2 [Ca(L) · 4(H₂O)] were obtained from self-assembly of CaCl₂ or MgSO₄ with olsalazine and their structures determined by single crystal X-ray diffraction. Both complexes are one-dimensional polymers, for complex 1 with crystal data: P2(1)/c, a = 9.5224(18), b = 11.309(2), c = 16.211(3) Å, β = 106.648(3)°, V = 1672.6(6) ų, Z = 4, R ₁ = 0.0695, wR ₂ = 0.2183, for complex 2 with crystal data: P4(3)2(1)2, a = 10.4006(2), b = 10.4006(2), c = 32.0746(10) Å, V = 3469.59(14) ų, Z = 8, R ₁ = 0.0332, wR ₂ = 0.1015. In the complexes, Mg and Ca adopt totally different coordination modes. Alkaline-earth Mg is six-coordinate octahedronal geometry, however, in 2, the local coordination geometry around calcium atom can be best described as a slightly distorted pentagonal bipyramid crystallizing in a homo-chiral space group. Olsalazine in both compounds also adopts dissimilar coordination modes.

Keywords:

• Olsalazine
• Crystal structure
• Calcium complex
• Magnesium complex

Acknowledgement

This work was supported by the Doctoral Sustentation Fund of Jiangxi University of Science and Technology.