Dielectric and optical properties of a new organic–inorganic hybrid phase transition material.

Crystal phase transformation is often accompanied by changes in corresponding physical properties. For instance, dielectric properties may undergo abrupt changes near the phase-transition temperatures. Currently, designing and synthesizing organic–inorganic hybrid materials with significant dielectric changes remains a field worth exploring. In this study, the compound [N(Et)₃CH₂Cl]₂[MnCl₄] (compound 1) was synthesized and characterized. The compound exhibited a reversible phase transition at 320 K, and dielectric permittivity anomalies were found near the phase-transition temperature. The observed changes in the space group from P1¯ (2) at LTP (below the phase-transition temperature) to P4₂/nmc (137) at HTP (above the phase-transition temperature) also proved an order–disorder phase transition. Significantly, compound 1 was green, and strong emission at 520 nm could be observed under ultraviolet excitation, which can be attributed to the d–d transition of the spin–orbital prohibition produced by the cations. Both dielectric and fluorescence properties of compound 1 may find applications in the fields of switchable, dielectric, and luminescent materials. [ABSTRACT FROM AUTHOR]