Synthesis, Crystal Structure and Luminescent Property of a New Holmium(Iii) Coordination Polymer Involving 2,5-Dihydroxy-1,4-Terephthalic Acid as Ligand

A novel coordination polymer {[Ho 2 (DHTA) 3 (H 2 O) 5 ]·H 2 O} n was synthesized by hydrothermal synthesis (DHTA = 2,5-dihydroxy-1,4-terephthalic acid). The Crystallographic data show that the crystal structure belongs to triclinic space system, P-1 space group with a = 9.6617(17) Å, b = 902(2) Å, c = 13.284(2) Å, α = 100.617(3)°, β = 92.765(2)°, γ = 106.715(2)°, V = 1429.6(4) Å 3 , Z = 2, C 24 H 24 O 24 Ho 2 , M r = 1026.290, D c = 2.377 g/cm 3 , F (000) = 982, R 1 = 0.0325, wR 2 = 0.0845. The structure and properties of the complex were analyzed and characterized by single crystal X-ray diffraction, IR, TGA, luminescence and PXRD. The {[Ho 2 (DHTA) 3 (H 2 O) 5 ]·H 2 O} n contains two Ho(III), the two metal centers Ho(III) are eight-coordinated. The adjacent metal centers are connected by DHTA and extend infinitely in all directions, forming a three-dimensional network structure. Meanwhile, hydrogen bonding and π-π stacking in the structure enhanced the stability of the complex. The TGA results show that from 400 to 650 o C, it is ascribed to the removal of the organic component, above 650 o C, the residual is Holmium(III) oxide (Ho 2 O 3 ). The luminescent results suggest that complex 1 has potential as a new green luminescence material.