A new 1D Cd(II) pyridinate polymer: Structure, second-harmonic generation response, dielectric and potential ferroelectric properties

A novel 1D polymer, [Cd(anp)2Br2]·H2O (1) (anp = 2-amino-5-nitropyridine), was synthesized through the solvothermal reaction of CdBr2·4H2O with anp. The main feature of 1 is a –Br–Cd(anp)2–Br– chain-like structure, which is formed by [anp–Cd–anp] subunits linked via μ2-Br bridges. The 1D chains are further assembled to form a 3D supramolecular architecture through hydrogen bondings. The one-center-A (acceptor)–D (donor) organic building blocks and non-centrosymmetric polar packing arrangement of 1 give rise to a dipole moment along the c-direction, enhancing the hyperpolarizability and thus resulting in a strong second-harmonic generation (SHG) response. The peak of temperature dependence of the dielectric constant of 1 indicates the Curie temperature TC of 138 °C (at 1 kHz). Moreover, complex 1 also exhibits potential ferroelectric properties.