Magnetic and electronic properties of alkali-metal intercalated 1,4-di(4-pyridyl)benzene

Abstract The investigation of superconducting and magnetic properties in alkali-metal-intercalated aromatic hydrocarbon compounds has been an active frontier in condensed matter physics. Herein, potassium- and rubidium-intercalated 1,4-di(4-pyridyl)benzene molecular crystals were successfully synthesized via a high-vacuum annealing technique. Magnetic measurements reveal that both intercalated crystals exhibit typical Curie paramagnetic behavior in the temperature range of 1.8–300 K. Combined experimental measurements and theoretical calculations confirm that the two synthesized compounds are paramagnetic semiconductors. The magnetic moment of approximately 0.30 μ B per molecule is attributed to the transfer of valence electrons from alkali metals to the π -molecular orbital of 1,4-di(4-pyridyl)benzene. Further theoretical calculations predict that the cesium-intercalated system exhibits characteristics of a paramagnetic semiconductor, whereas the sodium-intercalated system demonstrates a non-magnetic metallic state. This study provides new experimental and theoretical insights for understanding the electronic structure and magnetic properties of aromatic intercalation compounds, and reveals the critical role of intercalant selection in regulating their physical properties.