Structure and Photophysical Properties of an Upconversion Holmium-mercury Compound with a 2-D Layer-like Motif

Using a hydrothermal reaction, a novel holmium-mercury compound {[Ho(IA)(HIA)(2)(H2O)(2)](2)-(Hg3Br8)}(n)(nHgBr(2))center dot 2nNO(3) (1, FHA is isonicotinc acid) was synthesized and its crystal structure was characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in monoclinic system, space group P2/c with a = 13.0647(6), b = 9.4659(3), c = 26.0832(14) angstrom, beta = 97.522(4)degrees, V = 3197.9(2) angstrom(3), C36H36Br10Hg4Ho2N8O22, M-r = 2863.95, Z = 2, D, = 2.974 g/cm(3), mu(MoK alpha) = 18.331 mm(-1) and F(000) = 2575. It displays a two-dimensional (2D) layer-like structure. A solid-state photoluminescence experiment revealed that it shows upconversion green emission. The emission peaks should come from the I-5(8) -> (5)G(6) and S-5(2) -> I-5(8) characteristic emission of the 4f electrons of the Ho3+ ion. Compound 1 has a CIE chromaticity coordinate (0.1774, 0.526). A solid-state UV-visible diffuse reflectance spectrum unveiled that this compound has a wide optical band gap of 3.26 eV.

Automated summary

The novel holmium-mercury compound synthesized through a hydrothermal reaction exhibits unique characteristics such as crystal structure in monoclinic system, upconversion green emission in solid-state photoluminescence, and a wide optical band gap of 3.26 eV in solid-state UV-visible diffuse reflectance spectrum.