Crystal structure of catena-poly[[[triaquastrontium]-di-μ2-glycinato] dibromide]

Abstract

In the title coordination polymer, {[Sr(C2H5NO2)2(H2O)3]Br2}n, the Sr2+ ion and one of the water molecules are located on twofold rotation axes. The alkaline earth ion is nine-coordinated by three water O atoms and six O atoms of the carboxylate groups of four glycine ligands, two in a chelating mode and two in a monodentate mode. The glycine molecule exists in a zwitterionic form and bridges the cations into chains parallel to [001]. The Br− counter-anions are located between the chains. Intermolecular hydrogen bonds are formed between the amino and carboxylate groups of neighbouring glycine ligands, generating a head-to-tail sequence. Adjacent head-to-tail sequences are further interconnected by intermolecular N—H...Br hydrogen-bonding interactions into sheets parallel to (100). O—H...Br and O—H...O hydrogen bonds involving the coordinating water molecules are also present, consolidating the three-dimensional hydrogen-bonding network.

Keywords

• crystal structure
• glycine
• strontium
• N/O—H...Br/O hydrogen bonds