Highly lithium-ion selective ionophores: macrocyclic trinuclear complexes of methoxy-substituted arene ruthenium bridged by 2,3-pyridinediolate

Abstract

Metallacrowns composed of three Ru(alkylbenzene) units bridged by 2,3-pyridinediolate (pyO 2 2À) are known to act as Li + -selective ionophores. In this study, we synthesized analogues with anisole and 3,5-dimethylanisole as the arene ligands, i.e., [{Ru(anisole)(pyO 2 )} 3 ] and [{Ru(3,Their extraction properties for lithium and sodium picrates were investigated in a dichloromethane-water system at 25 1C. Compared to [{Ru(alkylbenzene)(pyO 2 )} 3 ], the new metallacrowns allow faster and greater extraction of Li + with much higher Li + /Na + selectivity. [{Ru(3,5-dimethylanisole)(pyO 2 )} 3 ] is superior to [{Ru(anisole)(pyO 2 )} 3 ] in the Li + /Na + selectivity. The extraction equilibrium constants and separation factors were determined for each system. The separation factor between Li + and Na + reaches 7.1 Â 10 4 with [{Ru(3,5-dimethylanisole)(pyO 2 )} 3 ]. The highly Li + -selective metallacrown was applied to the extraction separation of Li + from seawater.

Extraction spectrophotometry using a lithium-ion selective metallacrown: temperature effect on extraction reaction and application to determination of lithium in serum and seawater

“…Previously, we synthesized a metallacrown compound possessing extremely high extraction selectivity toward Li + , [{Ru(DMA)(pyO 2 )} 3 ] (Fig. 1 ), where DMA = 3,5-dimethylanisole and pyO 2 2– = 2,3-pyridinediolate [ 10 ]. This compound behaves as an electrically neutral ligand (L) like a crown ether, forms a cationic complex with an alkali metal ion (M + ), and extracts it into a nonpolar organic solvent as an ion pair with a hydrophobic monovalent anion (A – ): where subscripts o and w denote organic phase and aqueous phase, respectively.…”

Methoxy-Functionalized Triarylamine-Based Hole-Transporting Polymers for Highly Efficient and Stable Perovskite Solar Cells

“…CH 3 O-PTAA was designed by placing methyl group with methoxy group at the para position in a PTAA backbone to enhance the doping properties (Figure a). Favorable interactions of oxygen atom in the methoxy group to various metal ions allow good doping ability , and radical delocalization of triarylamine via resonance structures stabilizes the CH 3 O-PTAA radical cation, suppressing radical quenching (Scheme S1). ,− Such a design also has the potential to benefit the interactions between the polymers and adjacent perovskites through the oxygen lone pair electrons with uncoordinated Pb atoms .…”

Application of a Lithium-ion Selective Metallacrown to Extraction-Spectrophotometric Determination of Lithium in Saline Water

“…The aqueous and organic solutions (4 cm 3 each) were placed in a 10-cm 3 Teflon centrifuge tube, and mechanically shaken at 200 strokes/min in a chamber thermo-controlled at 25 ± 0.2 C; a shaking time of 8 -12 h was necessary to attain equilibrium for Li + that was extracted more slowly than Na + . 21 After centrifugation at 3000 rpm for 5 min, the alkali metals in the aqueous phase were determined by flame photometry. For determining the alkali metals in the organic phase, an aliquot (3 cm 3 ) of the organic phase was transferred into a Teflon beaker and evaporated to dryness; after adding concentrated nitric acid (2 cm 3 ), the solution was re-evaporated to dryness; the residue was dissolved in 0.06 mol dm -3 hydrochloric acid, and the concentrations of the alkali metals were determined by flame photometry.…”

“…We also reported new derivatives of [{M(arene)(pyO2)}3], [19][20][21] one of which is [{Ru(DMA)(pyO2)}3] (DMA = η 6 -3,5-dimethylanisole). The structure is shown in Fig.…”

“…1. [{Ru(DMA) (pyO2)}3] has an extremely high extraction selectivity for Li + ; the Li + /Na + separation factor in the extraction of alkali metal picrates with a dichloromethane solution of the metallacrown is 71000. 21 Because Li + is extracted as an ion pair between the Li + -metallacrown complex cation and the picrate anion, if the light absorption of the ion pair is not interfered by that of the free metallacrown in the organic phase, spectrophotometric determination of Li + (as the ion pair) is possible. Unfortunately, the light absorption of the yellow-colored picrate is completely overlapped with that of the metallacrown (orange).…”