Synthesis, characterization, and anomalous dielectric and conductivity performance of one-dimensional (bdaH)InSe2 (bda = 1,4-butanediamine)

A new indium selenide, namely (bdaH)InSe2 (1) (bda = 1,4-butanediamine) has been solvothermally synthesized and structurally characterized. It belongs to the non-centrosymmetric space group Fdd2. Its structure features an infinite one-dimensional anionic chain of [InSe2]nn− with monoprotonated [bdaH]+ as charge compensating cation. The organic [bdaH]+ cations are joined into a supramolecular one-dimensional chain via N–H···N hydrogen bonding, which further interacts with the inorganic chain via N–H···Se and C–H···Se hydrogen bonding, forming a supramolecular three-dimensional network. Based on such a well-defined structure, the thermal stability, optical, conductivity, and dielectric properties were systematically investigated, showing that dielectric constant, as well as conductivity, had a hump at about 95 °C, which could be attributed to water molecules in the crystal boundary.