Validation of Speciation Techniques: A Study of Chlorozincate(II) Ionic Liquids

Abstract

The speciation of chlorozincate(II) ionic liquids, prepared by mixing 1-octyl-3-methylimidazolium chloride, [C(8)mim]Cl, and zinc(II) chloride in various molar ratios, χ(ZnCl(2)), was investigated using Raman spectroscopy and differential scanning calorimetry; the Gutmann acceptor number, which is a quantitative measure of Lewis acidity, was also determined as a function of the composition. These results were combined with literature data to define the anionic speciation; in the neat liquid phase, the existence of Cl(-), [ZnCl(4)](2-), [Zn(2)Cl(6)](2-), [Zn(3)Cl(8)](2-), and [Zn(4)Cl(10)](2-) anions was confirmed. From two chlorozincate(II) ionic liquids with [C(2)mim](+) cations (χ(ZnCl(2)) = 0.33 and χ(ZnCl(2)) = 0.50), crystals have been obtained, revealing the structures of [C(2)mim](2)[ZnCl(4)] and [C(2)mim](2)[Zn(2)Cl(6)] forming three-dimensional hydrogen-bond networks. The compound [C(2)mim](2){Zn(4)Cl(10)} was crystallized from the χ(ZnCl(2)) = 0.75 composition, showing an open-framework structure, with the first example of zinc in a trigonal-bipyramidal chloride coordination. Reinvestigation of the electrospray ionization mass spectrometry of these systems demonstrated that it is an unreliable technique to study liquid-phase speciation.

On the Anion Exchange of PX3 (X = Cl, Br, I) in Ionic Liquids comprising Halide Anions

“…In all applications mentioned above, fundamental knowledge of the underlying mechanisms and behavior of the involved species are required to obtain reproducible results, high yields and defined morphologies. With focus on the actual molecular species in ILs, several spectroscopic in situ techniques have been employed, such as nuclear magnetic resonance (NMR),, Raman,, X‐ray photoelectron spectroscopy (XPS), or extended X‐ray absorption fine structure (EXAFS) , . Often combinations of complementary techniques are required to identify the active species.…”

Diethyldisulfoammonium chlorometallates as heterogeneous Brønsted–Lewis acidic catalysts for one‐pot synthesis of 14‐aryl‐7‐(N‐phenyl)‐14H‐dibenzo[a,j]acridines

“…These results are summarized in Table 4. Aromatic aldehydes bearing electron-donating or electron-withdrawing group produced very good amounts of dibenzoacridine in reasonable reaction time using the two catalysts without any side products (Table 4, entries [1][2][3][4][5][6] 4 ] salts were observed to be equivalent for the three-component one-pot synthesis of derivatives 1 under optimized conditions. The reactions of aliphatic aldehydes, namely n-butanal and paraformaldehyde, generated 14-alkyl-14H-dibenzo[a,j]xanthenes (2a, 2b) as products of incomplete reactions without formation of any dibenzoacridine derivatives (Table 4, entries 7 and 8).…”

“…The anionic composition determines the properties of chlorometallates which again depend on the types of metal chloride and the ratios of metal chloride to parent organic chloride. [3][4][5] The various developments of such ionic salts over the last two decades have recognized these chlorometallates/halometallates as functional materials with unique and useful properties including photophysical, magnetic, catalytic and semiconducting properties [6][7][8] The catalytic performances of these chlorometallates were examined for the three-component synthesis of novel 14-aryl-7-(N-phenyl)-14H-dibenzo[a,j]acridine derivatives (1) from the reaction of an equimolar mixture of 2-naphthol, N-phenyl-2-naphthylamine and aromatic aldehyde under solvent-free conditions at 100°C. The benzoacridine derivatives have a wide range of pharmacological activities such as antitumour, antiviral, antimicrobial, antimalarial, analgesic and anti-inflammatory activities.…”

Electrochemical Synthesis of Indium(0) Nanoparticles in Haloindate(III) Ionic Liquids

“…[37] In order to elucidate the anionic species present in each ionic liquid, particularly in the [N 11116 ]Br-InCl 3 system, Raman spectra for all three were acquired. The spectrum obtained for [C 8 mim][InCl 4 ] revealed only two bands in the region expected for InÀCl stretching frequencies: at ñ = 324 and at ñ = 113 cm…”