Magnetic and luminescent coordination networks based on imidazolium salts and lanthanides for sensitive ratiometric thermometry

The synthesis and characterization of six new lanthanide networks [Ln(L)(ox)(H₂O)] with Ln = Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺ and Yb³⁺ is reported. They were synthesized by solvo-ionothermal reaction of lanthanide nitrate Ln(NO₃)₃·xH₂O with the 1,3-bis(carboxymethyl)imidazolium [HL] ligand and oxalic acid (H₂ox) in a water/ethanol solution. The crystal structure of these compounds has been solved on single crystals and the magnetic and luminescent properties have been investigated relying on intrinsic properties of the lanthanide ions. The synthetic strategy has been extended to mixed lanthanide networks leading to four isostructural networks of formula [Tb_{1- x} Eu _x (L)(ox)(H₂O)] with x = 0.01, 0.03, 0.05 and 0.10. These materials were assessed as luminescent ratiometric thermometers based on the emission intensities of ligand, Tb³⁺ and Eu³⁺. The best sensitivities were obtained using the ratio between the emission intensities of Eu³⁺ (⁵D₀→⁷F₂ transition) and of the ligand as the thermometric parameter. [Tb_0.97Eu_0.03(L)(ox)(H₂O)] was found to be one of the best thermometers among lanthanide-bearing coordination polymers and metal-organic frameworks, operative in the physiological range with a maximum sensitivity of 1.38%·K^-1 at 340 K.

Syntheses, structures and magnetic properties of nine coordination polymers based on terphenyl-tetracarboxylic acid ligands

Nine coordination polymers based on dinuclear metal units/metal-carboxylate chains and 1,1′:4′,1′′-terphenyl-2′,4,4′′,5′-tetracarboxylic acid have been synthesized and structurally characterized. Complexes 2 and 9 show the weak ferromagnetic interactions.

Crystal structure of triaqua-(1,10-phenanthroline)-(dihydrogen-3,3′,3′′-(2,4,6-trioxo-1,3,5-triazinane-1,3,5-triyl)tripropanoato) cobalt(II)dihydrogen-3,3′,3′′-(2,4,6-trioxo-1,3,5-triazinane-1,3,5-triyl)tripropanoate, C72H82Co2N16O42

C72H82Co2N16O42, triclinic, P1̅, a = 15.7653(19) Å, b = 16.955(2) Å, c = 18.838(2) Å, α = 70.35(2)°, β = 87.78(2)°, γ = 63.73(2)°, V = 4216.5(8) Å3, Z = 2, R gt (F) = 0.0735, wR ref (F 2 ) = 0.1405, T = 296(2) K.

Three 3D coordination polymers based on [1,1′:4′,1′′-terphenyl]-2′,4,4′′,5′-tetracarboxylate demonstrating magnetic properties and selective sensing of Al3+/Fe3+over mixed ions

Three 3D coordination polymers have been synthesized by using the 1,1′:4′,1′′-terphenyl]-2′,4,4′′,5′-tetracarboxylate acid and Cd(ii),Co(ii) and Mn(ii), the Cd(ii) complex shows selective sensing Al³⁺/Fe³⁺ over the mixed metal ions.