Crystal structure, topology, tiling and photoluminescence properties of 4d–4f hetero-metal organic frameworks based on 3,5-pyrazoledicaboxylate

Abstract

Reaction of lanthanide oxides, cadmium acetate and 3,5-pyrazoledicarboxylic acid under hydrothermal conditions afforded five new isostructural 4d–4f hetero-metal organic frameworks, [Cd₃Ln(pdc)₃(H₂O)] {H₃pdc = 3,5-pyrazoledicarboxylic acid, Ln = La (1), Pr (2), Nd (3), Sm (4) and Eu (5)}. All compounds were characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The compounds feature a very interesting 3D structure built up from a secondary building unit, [Cd₁₂Ln₈(pdc)₆], and possess a new topology type and complicated unique tiling. The solid state photoluminescence properties of compounds 3–5 were investigated at room temperature.