Crystal structure of hexa-glycinium dodeca-iodo-triplumbate

Area of Science:

• Inorganic Chemistry
• Crystallography
• Materials Science

Background:

• The study focuses on lead-iodide compounds, a class known for diverse structural motifs and potential applications.
• Understanding the precise arrangement of atoms in such compounds is crucial for predicting their properties.
• Hexa-glycinium tetra-μ-iodido-octa-iodido-triplumbate, (GlyH)6[Pb3I12], represents a complex inorganic-organic hybrid material.

Purpose of the Study:

• To elucidate the crystal structure of hexa-glycinium tetra-μ-iodido-octa-iodido-triplumbate.
• To characterize the coordination environment of lead ions within the [Pb3I12]6- anion.
• To investigate the intermolecular interactions, including hydrogen bonding, that stabilize the crystal lattice.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the atomic arrangement.
• Analysis of bond lengths, angles, and coordination numbers to describe the [Pb3I12]6- anion.
• Identification and analysis of hydrogen bonding networks (C-H⋯I, N-H⋯I, O-H⋯I, N-H⋯O) and cation-cation interactions.

Main Results:

• The compound crystallizes in the triclinic space group P.
• A discrete [Pb3I12]6- anion was identified, featuring a central, holodirected Pb ion and two hemidirected Pb ions.
• The structure exhibits a novel dimeric cation arrangement of glycine (GlyH)+, observed for the first time, stabilized by hydrogen bonds.

Conclusions:

• The crystal structure of (GlyH)6[Pb3I12] has been successfully determined, revealing unique anionic and cationic arrangements.
• The [Pb3I12]6- anion displays distinct lead coordination geometries, contributing to the overall structural complexity.
• The discovery of dimeric glycine cations highlights new supramolecular assembly possibilities in hybrid materials.