[C4MPyr]2[Br20] - ein dreidimensionales Polybromidnetzwerk durch Synthese in ionischen Flüssigkeiten

Inorganic Synthesis Based on Reactions of Ionic Liquids and Deep Eutectic Solvents

Ionic liquids and deep eutectic solvents are of growing interest as solvents for the resource‐efficient synthesis of inorganic materials. This Review covers chemical reactions of various deep eutectic solvents and types of ionic liquids, including metal‐containing ionic liquids, [BF₄]⁻‐ or [PF₆]⁻‐based ionic liquids, basic ionic liquids, and chalcogen‐containing ionic liquids. Cases in which cations, anions, or both are incorporated into the final products are also included. The purpose of this Review is to raise caution about the chemical reactivity of ionic liquids and deep eutectic solvents and to establish a guide for their proper use.

Opening the Third Century of Polyhalide Chemistry: Thermally Stable Complex with "Trapped" Dichlorine

Unlike polyhalides of heavier halogens, polychlorides still remain exotic curiosities. Herein, we report preparation and investigation of complexes Cat₂ {[TeCl₆ ](Cl₂ )} (cat=1-methylpyridinium (1) and tetramethylammonium (2)) where dichlorine units are "trapped" by chlorotellurate(IV) anions via a system of non-covalent Cl⋅⋅⋅Cl interactions. Complex 2 reveals a record thermal stability (>100 °C) for inclusion compounds with Cl₂ , indications that such compounds can be used as solid Cl₂ source.

Synthesis and Characterization of [Br3 ][MF6 ] (M=Sb, Ir), as well as Quantum Chemical Study of [Br3 ]+ Structure, Chemical Bonding, and Relativistic Effects Compared with [XBr2 ]+ (X=Br, I, At, Ts) and [TsZ2 ]+ (Z=F, Cl, Br, I, At, Ts)

[Br₃ ][SbF₆ ] and [Br₃ ][IrF₆ ] were synthesized by interaction of BrF₃ with Sb₂ O₃ or iridium metal, respectively. The former compound crystallizes in the orthorhombic space group Pbcn (No. 60) with a=11.9269(7), b=11.5370(7), c=12.0640(6) Å, V=1660.01(16) ų , Z=8 at 100 K. The latter compound crystallizes in the triclinic space group P 1 ‾ (No. 2) with a=5.4686(5), b=7.6861(8), c=9.9830(9) Å, α=85.320(8), β=82.060(7), γ=78.466(7)°, V=406.56(7) ų , Z=2 at 100 K. Both compounds contain the cation [Br₃ ]⁺ , which has a bent structure and is coordinated by octahedron-like anions [MF₆ ]^- (M=Sb, Ir). Experimentally obtained cell parameters, bond lengths, and angles are confirmed by solid-state DFT calculations, which differ from the experimental values by less than 2 %. Relativistic effects on the structure of the tribromonium(1+) cation are studied computationally and found to be small. For the heaviest analogues containing At and Ts, however, pronounced relativistic effects are found, which lead to a linear structure of the polyhalogen cation.

Bromo- and Polybromoantimonates(V): Structural and Theoretical Studies of Hybrid Halogen-Rich Halometalate Frameworks

Cation-dependent reactions "[SbBr₆ ]^3- +Br₂ +HBr+CationBr_x " result in the formation of bromide/polybromide complexes with zero-, one-, two-, or three-dimensional supramolecular frameworks and different Br/Sb ratios (up to 11). Seven new compounds representing six structural types were characterized by XRD and thermogravimetric analysis and DFT calculations enabled estimation of the energies of the Br⋅⋅⋅Br contacts (1.1-4.6 kcal mol^-1 ).

Investigation of Large Polychloride Anions: [Cl11 ]- , [Cl12 ]2- , and [Cl13 ]. Angew Chem Int Ed Engl 2018;57:9136-9140. [PMID: 29737601 DOI: 10.1002/anie.201803486]

For decades the chemistry of polyhalides was dominated by polyiodides and more recently also by an increasing number of polybromides. However, apart from a few structures containing trichloride anions and a single report on an octachloride dianion, [Cl₈ ]^2- , polychlorine compounds such as polychloride anions are unknown. Herein, we report on the synthesis and investigation of large polychloride monoanions such as [Cl₁₁ ]^- found in [AsPh₄ ][Cl₁₁ ], [PPh₄ ][Cl₁₁ ], and [PNP][Cl₁₁ ]⋅Cl₂ , and [Cl₁₃ ]^- obtained in [PNP][Cl₁₃ ]. The polychloride dianion [Cl₁₂ ]^2- has been obtained in [NMe₃ Ph]₂ [Cl₁₂ ]. The novel compounds have been thoroughly characterized by NMR spectroscopy, single-crystal Raman spectroscopy, and single-crystal X-ray diffraction. The assignment of their spectra is supported by molecular and periodic solid-state quantum-chemical calculations.

Structural Proof for the First Dianion of a Polychloride: Investigation of [Cl8 ](2.)

The polychloride salt [CCl(NMe2 )2 ](+) 2 [Cl8 ](2-) was synthesized and crystallized in the ionic liquid [BMP]OTf. The compound was fully characterized by Raman spectroscopy as well as X-ray single-crystal structure determination, and represents the first example of a polychloride dianion to be described. Detailed gas-phase and solid-state calculations concerning the nature of the bonding situation were also performed.

Fluorine-Rich Fluorides: New Insights into the Chemistry of Polyfluoride Anions

Polyfluoride anions have been investigated by matrix-isolation spectroscopy and quantum-chemical methods. For the first time the higher polyfluoride anion [F5 ](-) has been observed under cryogenic conditions in neon matrices at 850 cm(-1) . In addition, a new band for the Cs(+) [F3 ](-) complex in neon is reported.

The formation of high-order polybromides in a room-temperature ionic liquid: from monoanions ([Br5 ](-) to [Br11 ](-) ) to the isolation of [PC16 H36 ]2 [Br24 ] as determined by van der Waals Bonding Radii

An unprecedented diversity of high-order bromine catenates (anionic polybromides) was generated in a tetraalkylphosphonium-based room temperature ionic liquid system. Raman spectroscopy was used to identify polybromide monoanions ranging from [Br5 ](-) to [Br11 ](-) in the bulk solution, while single-crystal X-ray diffraction identified extended networks of linked [Br11 ](-) units, forming a previously unknown polymeric [Br24 ](2-) dianion. This represents the largest polybromide species identified to date. In combination with recent work, this suggests that other, higher order molecular polybromide ions might be isolated.

Ionic liquids: new perspectives for inorganic synthesis?

Ionic liquids are credited with a number of unusual properties. These include a low vapor pressure, a wide liquid-phase range, weakly coordinating properties, and a high thermal/chemical stability. These properties are certainly of great interest for inorganic synthesis and the creation of novel inorganic compounds. On the other hand, the synthesis repertoire for preparing inorganic compounds has always been broad, ranging from syntheses in solutions and melts to solid-state reactions, and from crystal growth in the gas phase to high-pressure syntheses. What new aspects can ionic liquids then add to the synthesis of inorganic compounds? This Minireview uses some early examples to show that the use of ionic liquids indeed provides access to unusual inorganic compounds.