Synthesis, characterization and crystal structure of a glycylglycinate chelate of zinc(II)

Abstract

The reaction of glycylglycine (H2GG) with zinc oxide in a 2:1 ratio in water produced [Zn2(HGG1-)4(H2O)2] in high yield. The compound was characterized by elemental analysis, thermogravimetric analysis/differential scanning calorimetry, and FTIR spectroscopy. In addition, a single crystal structure revealed a binuclear complex with the H2GG ligand in two distinct coordination modes. The first coordination mode exhibits each Zn(II) site coordinated to a terminal, bidentate HGG1- via amine nitrogen atoms and the carbonyl amide oxygen atom. The second coordination mode shows a bridging tridentate HGG1- linked to one Zn site through the amine nitrogen and the carbonyl amide oxygen, and to the neighbouring Zn site through a carboxylate oxygen donor. In addition, each Zn site bonds to an aqua ligand to complete the six-coordinate coordination sphere. Crystal data: triclinic space group P-1, a = 7.374 Å, α = 105.57°, b = 10.054 Å, β = 91.084°, c = 10.756 Å, γ = 102.676°, V = 746.88 Å3.

Keywords

• Glycylglycine
• Zinc(II)
• Crystallography