Air-stable aryl derivatives of pentafluoroorthotellurate

We report on two different sets of air-stable derivatives of pentafluoroorthotellurate containing fluorinated and non-fluorinated aryl groups. The acid cis-PhTeF4OH was obtained in gram scale and further transformed to Ag[cis-PhTeF4O], which was used as a cis-PhTeF4O transfer reagent to obtain [PPh4][cis-PhTeF4O]. Furthermore, the synthesis of trans-(C6F5)2TeF3OH was achieved by a selective hydrolysis of trans-(C6F5)2TeF4 in the presence of KF and subsequent protonation by aHF. Quantum-chemical calculations show a higher acidity and robustness against fluoride abstraction for trans-(C6F5)2TeF3OH compared to cis-PhTeF4OH.


General procedures and materials
Unless otherwise mentioned, all experiments were performed under exclusion of moisture and oxygen using standard Schlenk techniques.Solids were handled in a MBRAUN UNIlab plus glovebox under an argon atmosphere (O2 < 0.5 ppm, H2O < 0.5 ppm).All experiments involving anhydrous HF (aHF) were performed in self-built PFA (perfluoroalkoxy alkanes) tubes connected to stainless steel metal valves and with a stainless steel vacuum line.Solvents were dried using a MBraun SPS-800 solvent system (CH2Cl2, MeCN, n-pentane), or with CaH2 (o-DFB, Et2O, CD3CN, CD2Cl2) before use and stored over 3 or 4 Å molecular sieves.PhTeF5 and Te(C6F5)2 were prepared according to literature procedures. 1,2All other reagents were purchased from standard commercial suppliers and used as received.NMR spectra were recorded on a JEOL 400 MHz ECS or JEOL 400 MHz ECZ spectrometer.All reported chemical shifts (δ in ppm) are referenced to the Ξ values given in IUPAC recommendations of 2008 using the 2 H signal of the deuterated solvent as internal reference. 3Multiplicity is indicated as follows: s = singlet, t = triplet, quint = quintet, dd = doublet of doublets, dt = doublet of triplets, dquint = doublet of quintets, tquint = triplet of quintets, m = multiplet.IR spectra were measured at room temperature on a Bruker ALPHA FTIR spectrometer with a diamond ATR inside a glovebox under an argon atmosphere, or on a Nicoleti S50 Advance FTIR by Thermo Fisher Scientific equipped with an ATR unit, with a Ge on KBr beam splitter and a DLaTGS-KBr detector for MIR and a solid-substrate beam splitter with a DLaTGS-PE detector for FIR.The ESI-TOF-Mass spectrometry measurements were performed on an Agilent 6210 ESI-TOF, Agilent Technologies, Santa Clara, CA, USA.Solvent flow rate was adjusted to 4 µL/min, spray voltage set to 4 kV.Drying gas flow rate was set to 15 psi (1 bar).Elemental analyses (CHNS) were carried out using a VARIO EL elemental analyzer.Crystal data were collected with MoKα radiation on a Bruker D8 Venture diffractometer with a CMOS area detector.Single crystals were picked −40 °C under nitrogen atmosphere and mounted on a 0.15 mm Mitegen micromount using perfluoroether oil.The structures were solved with the ShelXT 4 structure solution program using intrinsic phasing and refined with the ShelXL 5 refinement package using least squares minimizations by using OLEX2. 6For visualization the program Diamond V4.6.4 was used. 7CCDC 2184677, 2184678, 2184711, 2184734 and 2184735 contain the supplementary crystallographic data for this paper.These data are provided free of charge by The Cambridge Crystallographic Data Centre.Crystal data and other details of the structure analyses are summarized in Tables S1-S5.Suitable crystals for X-ray diffraction studies were obtained as indicated in the corresponding experimental entry (vide infra).

Synthesis of trans-(C 6 F 5 ) 2 TeF 3 OH (7)
K[(C6F5)2TeF3O] (150 mg, 0.26 mmol) was placed in a PFA tube equipped with a stir bar and connected to a stainless steel valve.After cooling to -196°C, aHF (1 mL) was condensed into the tube and the resulting suspension was stirred for 15 min at room temperature.All volatiles were evaporated through soda lime scrubbers to remove the unreacted aHF and the obtained residue was extracted with CH2Cl2 (10 mL).Removal of the solvent under reduced pressure afforded a colourless solid, which was identified as 7 (107 mg, 0.20 mmol, 77% yield).The marked signal (*) denotes an unidentified species.

CCDC number 2184735
Table S3.Crystal data and structure refinement for compound 5.
Single crystals of trans-(C6F5)2TeF2(OH)2 suitable for X-ray diffraction were obtained by cooling a saturated solution of the obtained colorless solid in n-hexane to -40 °C.

Quantum-chemical calculations
The Turbomole program 8 was used to perform calculations at the unrestricted Kohn-Sham DFT level, using the BP86 or B3LYP hybrid functional [9][10][11] (with RI 12 ) in conjunction with basis sets def-SV(P) and def2-TZVPP. 13Minima on potential energy surfaces were characterized by normal mode analysis.Thermochemical data is provided without counterpoise correction but including zero-point energy correction as obtained from harmonic vibrational frequencies.

Table S1 .
Crystal data and structure refinement for compound 1.

Table S2 .
Crystal data and structure refinement for compound 4.

Table S4 .
Crystal data and structure refinement for compound 6.