Work

High-Pressure Synthesis of Two Pb3(C3N6) Polymorphs Featuring Fully Deprotonated [C3N6]6– Melaminate Anions

Year: 2025

Type: article

Abstract: Graphitic carbon nitride (g-C 3 N 4 ), melamine, and their derivatives are of significant interest due to their diverse structural properties and potential applications in catalysis, energy storage, and materials science. In this study, two new compounds, both with the Pb 3 (C 3 N 6 ) chemical formula, were synthesized at pressures of 40(2) to 48(2) GPa through a direct reaction between Pb, C and N 2, or Pb and C 6 N 4, in laser-heated diamond anvil cells. Their crystal structures were solved and refined using synchrotron single-crystal X-ray diffraction. The two Pb 3 (C 3 N 6 ) polymorphs, namely tP 48-Pb 3 (C 3 N 6 ) and hP 72-Pb 3 (C 3 N 6 ), crystallize in the noncentrosymmetric space groups P 4̅2 1 m and P 6 1 22, respectively. Both solids contain the previously unknown hydrogen-free [C 3 N 6 ] 6– melaminate anion and were experimentally found recoverable to ambient conditions. Density functional theory calculations provide further insights into the structural and electronic properties, and reveal that both compounds are direct narrow band gap semiconductors.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.5c09198