Crystal structure of catena-poly[[methanoldioxidouranium(VI)]-μ-2-[5-(2-oxidophenyl)-1H-1,2,4-triazol-3-yl]acetato-κ2O:O′]

Abstract

In the title complex, [U(C10H7N3O3)O2(CH3OH)]n, the UVI cation has a typical pentagonal–bipyramidal environment with the equatorial plane defined by one N and two O atoms of one doubly deprotonated 2-[5-(2-hydroxyphenyl)-1H-1,2,4-triazol-3-yl]acetic acid ligand, a carboxylate O atom of the symmetry-related ligand and the O atom of the methanol molecule [U—N/Oeq 2.256 (4)–2.504 (5) Å]. The axial positions are occupied by two oxide O atoms. The equatorial atoms are almost coplanar, with the largest deviation from the mean plane being 0.121 Å for one of the O atoms. The benzene and triazole rings of the tetradentate chelating–bridging ligand are twisted by approximately 21.6 (2)° with respect to each other. The carboxylate group of the ligand bridges two uranyl cations, forming a neutral zigzag chain reinforced by a strong O—H...O hydrogen bond. In the crystal, adjacent chains are linked into two-dimensional sheets parallel to the ac plane by C/N—H...N/O hydrogen bonding and π–π interactions. Further weak C—H...O contacts consolidate the three-dimensional supramolecular architecture. In the solid state, the compound shows a broad medium intensity LMCT transition centred around 463 nm, which is responsible for its red colour.

Keywords

• crystal structure
• uranyl ion
• 1,2,4-triazole
• acetate group
• hydrogen bonding
• lmct transition