Flexible coordination environments of lanthanide complexes grown from chloride-based ionic liquids

Abstract

Hydrated lanthanide(III) chlorides, LnCl 3 ÁxH 2 O (Ln = La, Pr, Nd, Sm, Eu, Gd; x = 6-7) readily dissolve in the low melting ionic liquid 1-ethyl-3-methylimidazolium chloride ([C 2 mim]Cl) in an open vessel at 110 1C, and upon cooling crystallize as the anhydrous [C 2 mim] 3 [LnCl 6 ]. The crystal structures exhibit a face-centered packing arrangement of the [LnCl 6 ] 3À anions, with the cations located as slip aligned pairs in the void spaces which participate in hydrogen-bonding to chlorides. A second crystalline form of the Gd 3+ complex, GdCl 3 (OH 2 ) 4 Á2([C 2 mim]Cl), was isolated when the above reaction was conducted in a sealed system. For comparison, a third Gd 3+ compound was grown from the ionic liquid 1-butyl-3-methylimidazolium chloride ([C 4 mim]Cl) using the same unsealed conditions as above, and was found to be [C 4 mim] 3 [GdCl 6 ]. This compound exhibits a different packing arrangement to that observed for the [C 2 mim] + analogs. Based on these findings, ILs would appear to offer new crystallization process options based on their often high thermal stabilities and low to negligible vapor pressures.

One-pot synthesis of levulinic acid from cellulose in ionic liquids

“…2, the addition of InCl 3 facilitated the hydrolysis of glucose, that is, the metal ions-ionic liquid system mainly accelerated the reaction in the second stage of cellulose degradation. The complexes [InCl m (SO 4 ) n ] 2nÀ promoted rapid conversion of the a-anomers of glucose to the b-anomers through hydrogen bonding between oxygen atom in SO 4 2À or Cl À in metal chlorides and the hydroxyl groups (Hines et al, 2008). Compared with Table 1, the yields of lactic aicd and acetic acid increased greatly with the addition of InCl 3 .…”

Speciation of Rare‐Earth Metal Complexes in Ionic Liquids: A Multiple‐Technique Approach

“…[24][25][26][27][28][29][30] Additionally, ionic liquids are promising solvents for the crystallization and crystal engineering of metal complexes (coordination polymers) and they are able to trap unique coordination environments. [31][32][33][34][35][36][37][38] Besides these applications, ionic liquids have been reported to be interesting hosts for photochemical and spectroscopic studies and can be regarded as potential new optical materials. [39,40] For instance, these solvents were found to increase the photochemical stability of tetrakis b-diketonate complexes.…”

Microwave-assisted catalytic conversion of cellulose into 5-hydroxymethylfurfural in ionic liquids

“…Incidentally, there were also some reports on biomass conversion, which stated that microwave irradiation not only improved product yield, but also reduced reaction time [31]. When the reactions were carried out without ZrCl 4 or with ZrO 2 under the same reaction conditions ( [33]. These complexes played an important role in the isomerization of glucose into fructose, followed by dehydration to produce HMF.…”