Two temperature-dependent 2D heterometallic Cd(II)–Dy(III) coordination polymers exhibiting slow magnetic relaxation and luminescence properties

Two unique two-dimensional (2D) Cd(II)–Dy(III) heterometallic coordination polymers, {[DyCd(HPMA)(PMA)₂(H₂O)₄]·2H₂O}_n (1) and [DyCd(PAA)(PMA)₂(H₂O)₃]_n (2, PAA^– = phenylacetate), were prepared successfully based on the phenylmalonic acid (H₂PMA). The construction of two polymers is sensitive to the reaction temperature and can be synthesized directionally at room temperature and 90 °C, respectively. Complexes 1 and 2 display 2D layer structures that include dinuclear [Dy₂] cluster node and Dy(III)-based 1D zigzag chain motif severally. The Dy(III)-based units in two structures both are spaced well with the adjacent ones by the diamagnetic Cd(II)-based moieties. The magnetic studies reveal that 1 and 2 both display slow magnetic relaxation with temperature-dependent relaxation peaks producing an effective energy barrier (Δτ) of 74.5 and 32.1 K, separately. Furthermore, the solid-state photophysical properties of 1 and 2 show strong characteristic luminescent emissions of Dy(III) ion in the visible region.