A novel neodymium-mercury material with red photoluminescence: synthesis, characterization, photophysical properties and energy transfer mechanism

A novel neodymium-mercury material with a two-dimensional (2-D) layer-like structure, namely [Nd(HIA) 2 (H 2 O) 2 Hg 2 Cl 5 (IA)] n n (HgCl 2 )·5 n H 2 O· n Cl (marked as 1 ; HIA means isonicotinic acid), has been successfully synthesized through a solvothermal reaction. The crystal structure of compound 1 was determined by using the single-crystal X-ray diffraction method. The neodymium ion has eightfold coordination and shows a slightly distorted square anti-prism motif. The neodymium ions are interconnected via the isonicotinic acid ligands to form a one-dimensional (1-D) –Nd–(HIA) 4 –Nd–(HIA) 2 –Nd–(HIA) 4 –Nd–(HIA) 2 –Nd– chain. The 1-D chains are further interlinked by the Hg 2+ ions from the (Hg 2 Cl 5 ) − moieties to yield a 2-D layer. The Hg 2+ ions have two- and fourfold coordination motifs. Compound 1 shows a photoluminescence emission in the red region which is resulted from the 4 F 9/2 → 4 I 9/2 transition of the neodymium ions, as revealed by the energy transfer mechanism investigation. The CIE (Commission Internationale de I'Éclairage) chromaticity coordinates of compound 1 are 0.6868 and 0.313. The CT (color temperature) is 38399 K. Compound 1 has a wide band gap of 2.62 eV, as found by the solid-state UV–Visible diffuse reflectance spectrum. Graphical abstract A novel neodymium-mercury material with a two-dimensional layer-like structure has been successfully synthesized. The neodymium ion has eightfold coordination and shows a slightly distorted square anti-prism motif. The Hg 2+ ions have two- and fourfold coordination motifs. It exhibits a photoluminescence emission in the red region which is resulted from the 4 F 9/2 → 4 I 9/2 transition. The CIE chromaticity coordinates are 0.6868 and 0.313. The CT is 38399 K. It has a wide band gap of 2.62 eV.