Fluoride Abstraction Induced by Tris(pentafluoroethyl)difluorophosphorane: A Convenient Way to Synthesize Cationic -Heterocyclic Carbene- and Cyclic (Alkyl)(amino)carbene-Ligated Copper Alkyne and Arene Complexes.

We herein report the convenient synthesis of different -heterocyclic carbene (NHC)- and cyclic (alkyl)(amino)carbene (cAAC)-ligated copper cations using the weakly coordinating tris(pentafluoroethyl)trifluorophosphate counterion ( anion, [(CF)PF]). The reaction of the fluorido complexes [(carbene)CuF] (carbene = NHC, cAAC) - and the tris(pentafluoroethyl)difluorophosphorane (CF)PF in the presence of alkynes or arenes led to fluoride transfer from Cu to the phosphorane with formation of the cationic transition metal complexes [(carbene)Cu()] and the weakly coordinating counteranion [(CF)PF] (). Using this method, the complexes [(IDipp)Cu()] (IDipp = 1,3-bis(2,6-di--propylphenyl)-imidazolin-2-ylidene; = PhC≡CPh, ; PhC≡CMe, ), [(cAAC)Cu()] (cAAC = 1-(2,6-di--propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene; PhC≡CPh, ; PhC≡CMe, ), [(SIDipp)Cu(CMe)] (), (SIDipp = 1,3-bis(2,6-di--propylphenyl)-imidazolidine-2-ylidene), and [(cAAC)Cu(CMe)] () have been synthesized and characterized.

Synthesis of Partially Fluorinated Alkyl Triflates by Electrochemical Fluorination (Simons Process).

A scalable straightforward synthesis of monofluoro- and difluoromethyl triflate CF SO OCH F (M ) and CF SO OCHF (M ) through electrochemical fluorination (ECF, Simons process) of methyl triflate M in anhydrous hydrogen fluoride at nickel anodes is presented. The ECF method is also feasible for the preparation of the deuterated analogues CF SO OCD F (M ) and CF SO OCDF (M ). Surprisingly, no H/D exchange occurs during ECF of CF SO OCD (M ); this provides further evidence for a NiF /NiF -mediated ECF mechanism.

Alkylcyanoborate Anions: Building Blocks for Fluorine-Free Low-Viscosity, Electrochemically and Thermally Stable Ionic Liquids.

A set of mixed-substituted potassium alkylcyano- and alkylcyanofluoroborates has been synthesized using easily accessible starting compounds and characterized by elemental analysis, NMR and vibrational spectroscopy, and mass spectrometry. In addition, single-crystal structures of salts of the cyanoborate anions have been derived from X-ray diffraction experiments. The 1-ethyl-3-methylimidazolium room temperature ionic liquids ([EMIm] -RTILs) with the new borate anions have been synthesized and their physicochemical properties, that is, high thermal and electrochemical stability, low viscosity, and high conductivity, have been compared to the properties of related [EMIm] -RTILs.

Insights into structure-property relationships in ionic liquids using cyclic perfluoroalkylsulfonylimides.

Room temperature ionic liquids of cyclic sulfonimide anions cPFSI (ring size: = 4-6) with the cations [EMIm] (1-ethyl-3-methylimidazolium), [BMIm] (1-butyl-3-methylimidazolium) and [BMPL] (BMPL = 1-butyl-1-methylpyrrolidinium) have been synthesized. Their solid-state structures have been elucidated by single-crystal X-ray diffraction and their physicochemical properties (thermal behaviour and stability, dynamic viscosity and specific conductivity) have been assessed. In addition, the ion diffusion was studied by pulsed field gradient stimulated echo (PFGSTE) NMR spectroscopy.

Cyano(fluoro)borate and cyano(hydrido)borate ionic liquids: low-viscosity ionic media for electrochemical applications.

The synthesis and detailed characterization of low-viscosity room-temperature ionic liquids (RTILs) and [BnPhP] salts with the cyano(fluoro)borate anions [BF(CN)] (MFB), [BF(CN)] (DFB), and [BF(CN)] as well as the new mixed-substituted anion [BFH(CN)] (FHB) is described. The RTILs with [EMIm] or [BMPL] as countercations were obtained in yields of up to 98% from readily available alkali metal salts and in high purities that allow application in electrochemical devices. Trends in thermal stability, melting and freezing behavior, density, electrochemical stability, dynamic viscosity, specific conductivity and ion diffusivity have been assessed and compared to those of the related tetracyanoborate- and cyano(hydrido)borate-RTILs.

Prevalence of chronic pulmonary aspergillosis and the antifungal drug resistance of .

The aim of our study was to determine the prevalence of chronic pulmonary aspergillosis in pulmonary tuberculosis patients and the antifungal resistance of spp. isolates in Uzbekistan. Chronic pulmonary aspergillosis was detected in 11.

Ethyl-, vinyl- and ethynylcyanoborates: room temperature borate ionic liquids with saturated and unsaturated hydrocarbon chains.

Ethyl-, vinyl- and ethynyltricyano and dicyanofluoroborates were prepared on a gram scale from commercially available potassium trifluoroborates and trimethylsilylcyanide. Salt metathesis resulted in the corresponding EMIm-salts that are hydrophobic room-temperature ionic liquids (RTILs). The new RTILs exhibit unprecedented large electrochemical windows in combination with high thermal stabilities, low dynamic viscosities and high specific conductivities.

Stable and Storable N(CF ) Transfer Reagents.

Fluorinated groups are essential for drug design, agrochemicals, and materials science. The bis(trifluoromethyl)amino group is an example of a stable group that has a high potential. While the number of molecules containing perfluoroalkyl, perfluoroalkoxy, and other fluorinated groups is steadily increasing, examples with the N(CF ) group are rare.

Tris(pentafluoroethyl)difluorophosphorane: A Versatile Fluoride Acceptor for Transition Metal Chemistry.

Fluoride abstraction from different types of transition metal fluoride complexes [L MF] (M=Ti, Ni, Cu) by the Lewis acid tris(pentafluoroethyl)difluorophosphorane (C F ) PF to yield cationic transition metal complexes with the tris(pentafluoroethyl)trifluorophosphate counterion (FAP anion, [(C F ) PF ] ) is reported. (C F ) PF reacted with trans-[Ni(iPr Im) (Ar )F] (iPr Im=1,3-diisopropylimidazolin-2-ylidene; Ar =C F , 1 a; 4-CF -C F , 1 b; 4-C F -C F , 1 c) through fluoride transfer to form the complex salts trans-[Ni(iPr Im) (solv)(Ar )]FAP (2 a-c[solv]; solv=Et O, CH Cl , THF) depending on the reaction medium. In the presence of stronger Lewis bases such as carbenes or PPh , solvent coordination was suppressed and the complexes trans-[Ni(iPr Im) (PPh )(C F )]FAP (trans-2 a[PPh ]) and cis-[Ni(iPr Im) (Dipp Im)(C F )]FAP (cis-2 a[Dipp Im]) (Dipp Im=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) were isolated.

Innovative Syntheses of Cyano(fluoro)borates: Catalytic Cyanation, Electrochemical and Electrophilic Fluorination.

Different types of high-yield, easily scalable syntheses for cyano(fluoro)borates Kt[BF (CN) ] (n=0-2) (Kt=cation), which are versatile building blocks for materials applications and chemical synthesis, have been developed. Tetrafluoroborates react with trimethylsilyl cyanide in the presence of metal-free Brønsted or Lewis acid catalysts under unprecedentedly mild conditions to give tricyanofluoroborates or tetracyanoborates. Analogously, pentafluoroethyltrifluoroborates are converted into pentafluoroethyltricyanoborates.

Pentafluoroethylaluminates: A Combined Synthetic, Spectroscopic, and Structural Study.

Salts of the tetrakis(pentafluoroethyl)aluminate anion [Al(C F ) ] were obtained from AlCl and LiC F . They were isolated with different counter-cations and characterized by NMR and vibrational spectroscopy and mass spectrometry. Degradation of the [Al(C F ) ] ion was found to proceed via 1,2-fluorine shifts and stepwise loss of CF(CF ) under formation of [(C F ) AlF ] (n=1-4) as assessed by NMR spectroscopy and mass spectrometry and supported by results of DFT calculations.

Hydroxytricyanoborate Anion: Synthetic Aspects and Structural, Chemical, and Spectroscopic Properties.

In recent years, salts of the hydridotricyanoborate anion [BH(CN)] () have become readily available. In spite of the unusually high stability of the anion, it can be used as a valuable starting material for the preparation of selected tricyanoborates, for example, the boron-centered nucleophile B(CN). A further unprecedented example is the hydroxytricyanoborate anion [B(OH)(CN)] that is accessible by oxidation of (HO) with elemental bromine in water.

Boron: Its Role in Energy-Related Processes and Applications.

Boron's unique position in the Periodic Table, that is, at the apex of the line separating metals and nonmetals, makes it highly versatile in chemical reactions and applications. Contemporary demand for renewable and clean energy as well as energy-efficient products has seen boron playing key roles in energy-related research, such as 1) activating and synthesizing energy-rich small molecules, 2) storing chemical and electrical energy, and 3) converting electrical energy into light. These applications are fundamentally associated with boron's unique characteristics, such as its electron-deficiency and the availability of an unoccupied p orbital, which allow the formation of a myriad of compounds with a wide range of chemical and physical properties.

The pentafluoroethyltrihydridoborate anion: from shock sensitive salts to stable room temperature ionic liquids.

The reaction of pentafluoroethyllithium with BH·thf yields [CFBH] that is stable against HO, OH and air due to the electron withdrawing CF group. M[CFBH] (M = K, Cs) are shock sensitive solids whereas salts with organic cations such as the room temperature ionic liquid [EMIm][CFBH] are stable for years. [CFBH] is a mild reducing agent, which is also reflected by its electrochemical properties.

Cyanohydridoborate Anions: Synthesis, Salts, and Low-Viscosity Ionic Liquids.

High-yield syntheses up to molar scales for salts of [BH(CN) ] (2) and [BH (CN) ] (3) starting from commercially available Na[BH ] (Na5), Na[BH (CN)] (Na4), BCl , (CH ) SiCN, and KCN were developed. Direct conversion of Na5 into K2 was accomplished with (CH ) SiCN and (CH ) SiCl as a catalyst in an autoclave. Alternatively, Na5 is converted into Na[BH{OC(O)R} ] (R=alkyl) that is more reactive towards (CH ) SiCN and thus provides an easy access to salts of 2.

Activation of Acetonitrile with (C F ) PF and Amines.

Acetonitrile is deprotonated by a combination of the strong Lewis acid (C F ) PF and triethylamine. The resulting cyanomethyl function is bound to the phosphorus moiety, affording the highly stable salt [HNEt ][P(C F ) F (CH CN)]. Salt metathesis reactions furnished the corresponding [Cu(MeCN) ] and [Ag(MeCN)] derivatives in which the CH CN substituent of the anion [P(C F ) F (CH CN)] coordinates to the metal.

Borylation of fluorinated arenes using the boron-centred nucleophile B(CN) - a unique entry to aryltricyanoborates.

The potassium salt of the boron-centred nucleophile B(CN) () readily reacts with perfluorinated arenes, such as hexafluorobenzene, decafluorobiphenyl, octafluoronaphthalene and pentafluoropyridine, which results in KF and the K salts of the respective borate anions with one {B(CN)} unit bonded to the (hetero)arene. An excess of K leads to the successive reaction of two or, in the case of perfluoropyridine, even three C-F moieties and the formation of di- and trianions, respectively. Moreover, all of the 11 partially fluorinated benzene derivatives, CF H ( = 1-5), generally react with K to give new tricyano(phenyl)borate anions with high chemo- and regioselectivity.

Perfluoroalkyltricyanoborate and Perfluoroalkylcyanofluoroborate Anions: Building Blocks for Low-Viscosity Ionic Liquids.

The potassium perfluoroalkyltricyanoborates K[C F B(CN) ] [n=1 (1 d), 2 (2 d)] and the potassium mono(perfluoroalkyl)cyanofluoroborates K[C F BF(CN) ] [n=1 (1 c), 2 (2 c)] and [C F BF (CN)] [n=1 (1 b), 2 (2 b), 3 (3 b), 4 (4 b)] are accessible with perfect selectivities on multi-gram scales starting from K[C F BF ] and Me SiCN. The K salts are starting materials for the preparation of salts with organic cations, for example, [EMIm] (EMIm=1-ethyl-3-methylimidazolium). These [EMIm] salts are hydrophobic room-temperature ionic liquids (RTILs) that are thermally, chemically and electrochemically very robust, offering electrochemical windows up to 5.

Tris(pentafluoroethyl)germane: Deprotonation and Hydrogermylation Reactions.

Owing to the highly electron-withdrawing C F groups, the tris(pentafluoroethyl)germane (C F ) GeH represents an interesting Brønsted acidic compound. The germane is accessible by the treatment of the corresponding halogenogermanes (C F ) GeX (X=Cl, Br) with Bu SnH. After clarifying its molecular structure in the solid state by X-ray diffraction, the acidity of (C F ) GeH was examined by treatment with different bases, for example, 1,8-bis(dimethylamino)naphthalene.

Anhydrous, Homoleptic Lanthanide Frameworks with the Pentafluoroethyltricyanoborate Anion.

Pentafluoroethyltricyanoborate frameworks of rare-earth metal ions of the general formula [Ln{CFB(CN)}(OH)] (Ln = La, Eu, Ho; n = 0, 3; [Ln1(OH)]) were synthesized using the oxonium salt (HO)[CFB(CN)] ((HO)1) and lanthanide chlorides LnCl·nHO as starting compounds. Single-crystals of [La{CFB(CN)}] ([La1]) are obtained from the room temperature ionic liquid (RTIL) [EMIm]1 using either a ionothermal approach or by recrystallization of anhydrous microcrystalline [La1] that is obtained from reactions in aqueous media after drying in a vacuum. Removal of water from [Ln1(OH)] (Ln = Eu, Ho) to give microcrystalline [Ln1] is achieved in a vacuum at elevated temperatures.

Protonation versus Oxonium Salt Formation: Basicity and Stability Tuning of Cyanoborate Anions.

Anhydrous H[BH (CN) ] crystallizes from acidic aqueous solutions of the dicyanodihydridoborate anion. The formation of H[BH (CN) ] is surprising as the protonation of nitriles requires strongly acidic and anhydrous conditions but it can be rationalized based on theoretical data. In contrast, [BX(CN) ] (X=H, F) gives the expected oxonium salts (H O)[BX(CN) ] while (H O)[BF (CN) ]/H[BF (CN) ] is unstable.

Bismuth Perfluoroalkylphosphinates: New Catalysts for Application in Organic Syntheses.

Commercially available BiPh was treated with perfluoroalkylphosphinic acids [for example, (C F ) P(O)OH] to generate novel, highly Lewis acidic bismuth(III) perfluoroalkylphosphinates of the type Ph Bi[R PO ] (x=0, 1, 2) (R =-C F , -C F ). The first bismuth(V) perfluoroalkylphosphinate, Ph Bi[(C F ) PO ] , was synthesized from Ph BiCl and Ag[(C F ) PO ]. Examples for the successful application of the catalytically active bismuth(III) and bismuth(V) phosphinates in carbon-carbon bond forming reactions, such as Friedel-Crafts acylation and alkylation, Diels-Alder, Strecker and Mannich reaction, are presented.

Pentafluoroethyl Bismuth Compounds.

A series of tris-, bis-, and mono(pentafluoroethyl)bismuthanes of the type (C F ) BiX (X=F, Cl, Br, I) and transition metal complexes are accessible by a sophisticated pentafluoroethylation protocol. Chemical properties, induced by the strongly electron-withdrawing character of C F groups, are described for representative examples. Moreover, the first molecular structures of perfluoroalkyl bismuthanes and bismuthates obtained by X-ray diffraction are presented.