Search

A new concept for the synthesis of dialkyl chloronium cations [R−Cl−R]+ is described (R=CH3, CH2CF3), that allows the formation of fluorinated derivatives. By utilizing the xenonium salt [XeOTeF5][M(OTeF5)n] (M=Sb, n=6; M=Al, n=4) chlorine atoms of chloroalkanes or the deactivated chlorofluoroalkane CH2ClCF3 are oxidized and removed as ClOTeF5 leading to the isolation of the corresponding chloronium salt. Since the resulting highly electrophilic cation [Cl(CH2CF3)2]+ is able to alkylate weak nucleophiles, this compound can be utilized for the introduction of a fluorinated alkyl group to those. In addition, the fluorinated alkyl chloronium cation displays a high hydride ion affinity, enabling the activation of linear hydrocarbons by hydride abstraction even at low temperatures ultimately leading to the formation of branched carbocations. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report on an unexpected reaction between ammonia and potassium ozonide dissolved in liq. NH3 resulting in the formation of peroxynitrite, [ONOO]−, which exclusively happens in the presence of a specific partially fluorinated aniline‐based ammonium cation. High‐resolution structural data of the peroxynitrite anion in cis‐conformation have been obtained. We further studied this molecule anion by single crystal Raman spectroscopy. The cis and trans isomers of peroxynitrite were analysed computationally with respect to their relative energies, the cis‐trans transition barrier and their decomposition pathways to the nitrate anion. By experimentally examining cations decorated with fluorine ligands to different degrees, we demonstrate that fluorine specific interactions play a crucial role in the unexpected formation of peroxynitrite and as a conspicuously structure directing factor for the underlying crystalline solid phases, exhibiting distinct micro‐separations of fluorine and hydrogen enriched regions. [ABSTRACT FROM AUTHOR]

In this work, we analyzed trifluoromethyl fluorosulfonate (CF3OSO2F) and trifluoromethoxy sulfur pentafluoride (CF3OSF5) regarding their potential use as dielectrics by investigating some of their intrinsic and extrinsic properties. Both compounds show a higher breakdown voltage than SF6 with averaged relative breakdown voltages of 1.3±0.2 for CF3OSO2F and 1.4±0.2 for CF3OSF5 compared to SF6 with 1.0. Like the dielectric (CF3)2CFCN, both compounds decompose during the breakdown process. The decomposition products were analyzed by IR spectroscopy and GCIR methods. Furthermore, the molecular structures of both gaseous compounds CF3OSO2F and CF3OSF5 have been determined by in situ crystallization, and their physical properties were determined as well. [ABSTRACT FROM AUTHOR]

Herein we report on the formation of the adduct salts [Xe(OTeF5)(pyF)][Al(OTeF5)4] (pyF = C5F5N, C5H3F2N) by abstraction of an –OTeF5 group from Xe(OTeF5)2 with the Lewis superacid Al(OTeF5)3 and subsequent adduct formation of the generated [XeOTeF5]+ cation with fluorinated pyridines. These salts represent the first xenonium cations with the weakly coordinating [Al(OTeF5)4]− anion. The strong oxidizing property of these compounds is further assessed. [ABSTRACT FROM AUTHOR]

The compounds [Me3N(C6H3(CF3)2)][BF4] and [Me3N(C6H3(CH3)2)][BF4] were synthesized from commercially available starting materials and fully characterized by single-crystal X-ray diffraction, NMR, IR and Raman spectroscopy, as well as mass spectrometry. Both ammonium cations show potential for applications in crystal engineering due to their structure directing properties in the solid state. [ABSTRACT FROM AUTHOR]

Preparation and characterization of the dimeric Lewis superacid [Al(OTeF5)3]2 and various solvent adducts is presented. The latter range from thermally stable adducts to highly reactive, weakly bound species. DFT calculations on the ligand affinity of these Lewis acids were performed in order to rank their remaining Lewis acidity. An experimental proof of the Lewis acidity is provided by the reaction of solvent‐adducts of Al(OTeF5)3 with [PPh4][SbF6] and OPEt3, respectively. Furthermore, their reactivity towards chloride and pentafluoroorthotellurate salts as well as (CH3)3SiCl and (CH3)3SiF is shown. This includes the formation of the dianion [Al(OTeF5)5]2−. [ABSTRACT FROM AUTHOR]

Organic fluoronium ions can be described as positively charged molecules in which the most electronegative and least polarizable element fluorine engages in two partially covalent bonding interactions to two carbon centers. While recent solvolysis experiments and NMR spectroscopic studies on a metastable [C–F–C]+ fluoronium ion strongly support the divalent fluoronium structure over the alternative rapidly equilibrating classical carbocation, the model system has, to date, eluded crystallographic analysis to confirm this phenomenon in the solid state. Herein, we report the single crystal structure of a symmetrical [C–F–C]+ fluoronium cation. Besides its synthesis and crystallographic characterization as the [Sb2F11]− salt, vibrational spectra are discussed and a detailed analysis concerning the nature of the bonding situation in this fluoronium ion and its heavier halonium homologues is performed, which provides detailed insights on this molecular structure. Unlike other halogen atoms, the ability for fluorine to exist in a [C–X–C]+ connectivity pattern has only been shown in spectroscopic studies. Here the authors present a single crystal structure of a fluoronium cation, characterized by X-ray diffraction. [ABSTRACT FROM AUTHOR]

The weakly coordinating properties of the [Al(OTeF5)4]– anion were studied by the synthesis and characterization of its tetraalkylammonium salts [NAlk4][Al(OTeF5)4] [Alk4 = –(CH3)4, –(C2H5)4, –(C2H5)3CH3, –(C3H7)4, –(C4H9)4]. The one‐pot synthesis includes formation of the Brønsted acid in 1,2–difluorobenzene, H[Al(OTeF5)4](solv.), and its reaction with [NAlk4]Cl [Alk4 = –(CH3)4, –(C2H5)4, –(C2H5)3CH3, –(C3H7)4, –(C4H9)4] to the corresponding salts. Single crystals were obtained for [N(C4H9)4][Al(OTeF5)4] and characterized by X‐ray diffraction analysis. [ABSTRACT FROM AUTHOR]

The weakly coordinating properties of the [Al(OTeF5)4]– anion were studied by the synthesis and characterization of its tetraalkylammonium salts [NAlk4][Al(OTeF5)4] [Alk4 = –(CH3)4, –(C2H5)4, –(C2H5)3CH3, –(C3H7)4, –(C4H9)4]. The one‐pot synthesis includes formation of the Brønsted acid in 1,2–difluorobenzene, H[Al(OTeF5)4](solv.), and its reaction with [NAlk4]Cl [Alk4 = –(CH3)4, –(C2H5)4, –(C2H5)3CH3, –(C3H7)4, –(C4H9)4] to the corresponding salts. Single crystals were obtained for [N(C4H9)4][Al(OTeF5)4] and characterized by X‐ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Salts of the weakly coordinating anions [Ga(OTeF5)4]− as well as [Ga(Et)(OTeF5)3]− and the neutral Ga2(Et)3(OTeF5)3 were synthesized and characterized by spectroscopic methods and single‐crystal X‐ray diffraction. Ga2(Et)3(OTeF5)3 was formed by treating GaEt3 with pentafluoroorthotelluric acid (HOTeF5) and reacted with PPh4Cl and CPh3Cl to [PPh4][Ga(Et)(OTeF5)3] and [CPh3][Ga(Et)(OTeF5)3]. In contrast, Ag[Ga(OTeF5)4] was prepared from AgOTeF5 and GaCl3 and was used as a versatile starting material for further reactions. Starting with Ag[Ga(OTeF5)4] the substrates [PPh4][Ga(OTeF5)4] and [CPh3][Ga(OTeF5)4] were formed from PPh4Cl and CPh3Cl. [ABSTRACT FROM AUTHOR]

Salts of the weakly coordinating anions [Ga(OTeF5)4]− as well as [Ga(Et)(OTeF5)3]− and the neutral Ga2(Et)3(OTeF5)3 were synthesized and characterized by spectroscopic methods and single‐crystal X‐ray diffraction. Ga2(Et)3(OTeF5)3 was formed by treating GaEt3 with pentafluoroorthotelluric acid (HOTeF5) and reacted with PPh4Cl and CPh3Cl to [PPh4][Ga(Et)(OTeF5)3] and [CPh3][Ga(Et)(OTeF5)3]. In contrast, Ag[Ga(OTeF5)4] was prepared from AgOTeF5 and GaCl3 and was used as a versatile starting material for further reactions. Starting with Ag[Ga(OTeF5)4] the substrates [PPh4][Ga(OTeF5)4] and [CPh3][Ga(OTeF5)4] were formed from PPh4Cl and CPh3Cl. [ABSTRACT FROM AUTHOR]

Six different salts of the weakly coordinating anion [Al(OTeF5)4]– were synthesized and characterized spectroscopically. The alkali and silver salts M[Al(OTeF5)4] (M = Ag, Li, Na, K, Rb) were obtained by a protonation reaction involving the Brønsted acid H[Al(OTeF5)4](solv). In the case of the lithium and silver salt, crystals of the solvent‐coordinated [Li(thf)4][Al(OTeF5)4(thf)2] and [Ag(thf)6][Al(OTeF5)4(thf)2] were characterized by low‐temperature X‐ray diffraction, revealing a sixfold coordinated central aluminum atom. By a metathesis reaction, the oxidizing nitrosonium salt [NO][Al(OTeF5)4] was obtained and its reactivity was demonstrated by a reaction with white phosphorus. By low‐temperature NMR spectroscopy the selective formation of [NOP4]+ species was confirmed. All of the prepared salts represent useful starting materials for the further introduction of the weakly coordinating anion [Al(OTeF5)4]– into a given system. [ABSTRACT FROM AUTHOR]

The synthesis and structural characterisation of the difluorido organo gold(iii) complexes [AuClF2(SIMes)] and [AuF2(OTeF5)(SIMes)] are presented. The substitution of a fluorido ligand in [AuF3(SIMes)] by an OTeF5 group increases the Lewis acidity of the Au moiety. A scale for carbene affinities is presented, which correlates calculated and experimental values for the Lewis acidity of the metal centre in akin compounds. [ABSTRACT FROM AUTHOR]

The polybromide salts [BrC(NMe2)2]2[Br8] and [BrC(NMe2)2][Br3] were synthesized in the ionic liquid [BMP][OTf] (1-butyl-1-methyl-pyrrolidinium triflate). The compounds were characterized by Raman, NMR, and X-ray single crystal structure determination as well as quantum-chemical calculations. The polybromide dianion [Br8]2- structure shows similarities to the very recently reported structure of the first octachloride [Cl8]2-. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Das Polychloridsalz [CCl(NMe2)2]+2[Cl8]2− wurde in der ionischen Flüssigkeit [BMP]OTf synthetisiert und kristallisiert. Die Verbindung wurde mittels Raman ‐ Spektroskopie und Einkristallröntgenstrukturanalyse vollständig charakterisiert und enthält das erste literaturbekannte Polychloriddianion. Des Weiteren wurden detaillierte Gasphasen ‐ und Festkörperrechnungen bezüglich der Bindungssituation durchgeführt. Alles Chlor! Das neuartige Polychloridsalz [CCl(NMe2)2]+2[Cl8]2− (Tetramethylchloramidiniumoctachlorid) wurde aus einer ionischen Flüssigkeit kristallisiert und vollständig charakterisiert. Es ist das erste literaturbekannte Polychloriddianion. Detaillierte quantenchemische Rechnungen geben Einblicke in die Bindungssituation und Struktur. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A new concept for the synthesis of dialkyl chloronium cations [R-Cl-R] + is described (R=CH 3 , CH 2 CF 3 ), that allows the formation of fluorinated derivatives. By utilizing the xenonium salt [XeOTeF 5 ][M(OTeF 5 ) n ] (M=Sb, n=6; M=Al, n=4) chlorine atoms of chloroalkanes or the deactivated chlorofluoroalkane CH 2 ClCF 3 are oxidized and removed as ClOTeF 5 leading to the isolation of the corresponding chloronium salt. Since the resulting highly electrophilic cation [Cl(CH 2 CF 3 ) 2 ] + is able to alkylate weak nucleophiles, this compound can be utilized for the introduction of a fluorinated alkyl group to those. In addition, the fluorinated alkyl chloronium cation displays a high hydride ion affinity, enabling the activation of linear hydrocarbons by hydride abstraction even at low temperatures ultimately leading to the formation of branched carbocations., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

A one pot room temperature synthesis of thionyl tetrafluoride (SOF4) from elemental fluorine (F2) and thionyl fluoride (SOF2) is reported. The selective decagram scale process (100 mmol) allows a quantitative preparation of SOF4 with high purity. The solid-state structure has also been elucidated and compared with the reported gas-phase one. The use of this reagent for the formation of the emerging pentafluorooxosulfate [cat][OSF5] anions led to the preparation of multiple ion-pairs (cat = Ag, NEt3Me, PPN, PPh4) in different organic solvents. The SuFEx reservoir ability of this anion was studied and by tuning the solvent system, the reactivity of pure thionyl tetrafluoride was observed using Ag[OSF5] in THF and acetone., (© 2024 Wiley‐VCH GmbH.)

Lewis acidic boron compounds are ubiquitous in chemistry due to their numerous applications, yet tuning and optimizing their properties towards different purposes is still a challenging field of research. In this work, the boron-based Lewis acid B[OTeF 3 (C 6 F 5 ) 2 ] 3 was synthesized by reaction of the teflate derivative HOTeF 3 (C 6 F 5 ) 2 with BCl 3 or BCl 3  ⋅ SMe 2 . This new compound presents a remarkably high thermal stability up to 300 °C, as well as one of the most sterically encumbered boron centres known in the literature. Theoretical and experimental methods revealed that B[OTeF 3 (C 6 F 5 ) 2 ] 3 exhibits a comparable Lewis acidity to that of the well-known B(C 6 F 5 ) 3 . The affinity of B[OTeF 3 (C 6 F 5 ) 2 ] 3 towards pyridine was accessed by Isothermal Titration Calorimetry (ITC) and compared to that of B(OTeF 5 ) 3 and B(C 6 F 5 ) 3 . The ligand-transfer reactivity of this new boron compound towards different fluorides was demonstrated by the formation of an anionic Au(III) complex and a hypervalent iodine(III) species., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

We report on an unexpected reaction between ammonia and potassium ozonide dissolved in liq. NH 3 resulting in the formation of peroxynitrite, [ONOO] - , which exclusively happens in the presence of a specific partially fluorinated aniline-based ammonium cation. High-resolution structural data of the peroxynitrite anion in cis-conformation have been obtained. We further studied this molecule anion by single crystal Raman spectroscopy. The cis and trans isomers of peroxynitrite were analysed computationally with respect to their relative energies, the cis-trans transition barrier and their decomposition pathways to the nitrate anion. By experimentally examining cations decorated with fluorine ligands to different degrees, we demonstrate that fluorine specific interactions play a crucial role in the unexpected formation of peroxynitrite and as a conspicuously structure directing factor for the underlying crystalline solid phases, exhibiting distinct micro-separations of fluorine and hydrogen enriched regions., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)