In situ synthesis, crystal structures, topology and photoluminescent properties of poly[di-μ-aqua-di-aqua-[μ3-4-(1 H-tetra-zol-1-id-5-yl)benzoato-κ4 O: O, O': O'']barium(II)] and poly[μ-aqua-di-aqua-[μ3-4-(1 H-tetra-zol-1-id-5-yl)benzoato-κ4 O: O, O': O']strontium(II)]

Abstract

Two alkaline-earth coordination compounds, [Ba(C₈H₄N₄O₂)(H₂O)₄] _n , (I), and [Sr(C₈H₄N₄O₂)(H₂O)₃] _n , (II), from the one-pot hydrolysis transformation of benzoyl chloride and the in situ self-assembled [2 + 3] cyclo-addition of nitrile are presented. These coordination compounds are prepared by reacting 4-cyano-benzoyl chloride with divalent alkaline-earth salts (BaCl₂ and SrCl₂) in aqueous solution under hydro-thermal conditions. The mononuclear coordination compounds (I) and (II) show the same mode of coordination of the organic ligands. The cohesion of the crystalline structures is provided by hydrogen bonds and π-stacking inter-actions, thus forming three-dimensional supra-molecular networks. The two compounds have a three-dimensional (3,6)-connected topology, and the structural differences between them is in the number of water mol-ecules around the alkaline earth metals. Having the same emission frequencies, the compounds exhibit photoluminescence properties with a downward absorption value from (I) to (II).

Keywords: FT–IR; TGA; alkaline earth complexes; crystal structure; in situ synthesis; photoluminescence; tetra­zol-carboxyl­ate coordination compounds; topology.