Photochemistry with Chlorine Trifluoride: Syntheses and Characterization of Difluorooxychloronium(V) Hexafluorido(non)metallates(V), [ClOF2][MF6] (M=V, Nb, Ta, Ru, Os, Ir, P, Sb)

Abstract A photochemical route to salts consisting of difluorooxychloronium(V) cations, [ClOF2]+, and hexafluorido(non)metallate(V) anions, [MF6]− (M=V, Nb, Ta, Ru, Os, Ir, P, Sb) is presented. As starting materials, either metals, oxygen and ClF3 or oxides and ClF3 are used. The prepared compounds were characterized by single‐crystal X‐ray diffraction and Raman spectroscopy. The crystal structures of [ClOF2][MF6] (M=V, Ru, Os, Ir, P, Sb) are layer structures that are isotypic with the previously reported compound [ClOF2][AsF6], whereas for M=Nb and Ta, similar crystal structures with a different stacking variant of the layers are observed. Additionally, partial or full O/F disorder within the [ClOF2]+ cations of the Nb and Ta compounds occurs. In all compounds reported here, a trigonal pyramidal [ClOF2]+ cation with three additional Cl⋅⋅⋅F contacts to neighboring [MF6]− anions is observed, resulting in a pseudo‐octahedral coordination sphere around the Cl atom. The Cl−F and Cl−O bond lengths of the [ClOF2]+ cations seem to correlate with the effective ionic radii of the M V ions. Quantum‐chemical, solid‐state calculations well reproduce the experimental Raman spectra and show, as do quantum‐chemical gas phase calculations, that the secondary Cl⋅⋅⋅F interactions are ionic in nature. However, both solid‐state and gas‐phase quantum‐chemical calculations fail to reproduce the increases in the Cl−O bond lengths with increasing effective ionic radius of M in [MF6]− and the Cl−O Raman shifts also do not generally follow this trend.


Basis set details for quantum-chemical solid-state calculations TZVP basis set for O
The basis set for O was taken from a previous study. [3] TZVP basis set for F The basis set for F was taken from a previous study. [3] TZVP basis set for Cl The basis set for Cl was taken from a previous study. [4] TZVP basis set for V The basis set for V was taken from a previous study. [5] TZVP basis set for As The starting point was the molecular def-TZVP basis set. [6] The exponents of the outermost s and p functions were fixed to 0.13 and the exponents of the other s and p functions in the valence space were reoptimized for the arsenic atom in its ground state. The exponent of the outermost d primitive was kept fixed, while the exponents of the other d functions were optimised for the arsenic atom in its ground state. An f-type polarization function with an exponent of 0.433 was added (def2-TZVP basis set). Finally, the outermost s and p functions were combined into a single sp-type function to increase the efficiency of the CRYSTAL code. The resulting energy loss w.r.t unmodified def2-TZVP basis set is 0.2 mH. The final basis set in CRYSTAL input format is as follows:

TZVP basis set for Sb
The def2-TZVP basis set with a 28-electron effective core potential was used as a starting point. [6] We fixed the exponents of the outermost s and p functions to 0.11 and reoptimized the exponents of the other s and p functions in the valence space for the antimony atom in its ground state. Finally, the outermost s and p functions were combined into one sp-type function. The resulting energy loss with respect to the original molecular basis set is 4.7 mH. The exponent of the outermost d-function was increased from 0.14 to 0.217. The energy cost of this change was only 0.14 mH. The steep f-type polarization function with an exponent of 1.1 was removed. The final basis set in CRYSTAL input format is as follows:

TZVP basis set for Nb
The basis set was derived from the molecular Karlsruhe def2-TZVP basis set (28-electron effective core potential). [6] The diffuse outermost s-exponents were increased from 0.033 and 0.086 to 0.13 and 0.30, respectively. The outermost p-type function with an exponent of 0.03 was removed and the exponents of the two remaining outermost p-type functions were changed from 0.09 to 0.13 and 0.2797 to 0.30. The two outermost s and p functions were both then combined into two sptype functions. The most diffuse d-type function (exponent 0.10) was removed and the inner (3d) function was decontracted to (2d1d). The f-type polarization function was removed. The final basis set in CRYSTAL input format is as follows:

TZVP basis set for Ta
The basis set was derived from the molecular Karlsruhe def2-TZVP basis set (60-electron effective core potential). [6] The diffuse outermost s-and p-type functions with exponents of 0.039 and 0.065 were removed. The exponent of the outermost s-type function was increased from 0.10 and 0.11. The exponent of the outermost p-type function was changed from 0.27 to 0.11 and combined with the outermost s function into a single sp-type function. The most diffuse d-type function (exponent 0.088) was removed and the inner (3d) function was decontracted to (2d1d). The f-type polarization function was removed. The final basis set in CRYSTAL input format is as follows:

TZVP basis set for Ir
The basis set was derived from the molecular Karlsruhe def2-TZVP basis set (60-electron effective core potential). [6] The diffuse outermost s-and p-type functions with exponents of 0.05 and 0.056 were removed. The exponent of the outermost p-type function was changed from 0.33 to 0.14 and it was combined with the outermost s function into a single sp-type function. The exponents of the two outermost d-type functions were increased to 0.18 and 0.36. The f-type polarization function was removed. The final basis set in CRYSTAL input format is as follows:

TZVP basis set for Ru
The basis set was derived from the molecular Karlsruhe def2-TZVP basis set (28-electron effective core potential). [6] The diffuse outermost s-exponents were increased from 0.039 and 0.107 to 0.13 and 0.26, respectively. The outermost p-type function with an exponent of 0.037 was removed and the exponents of the two remaining outermost p-type functions were changed from 0.115 to 0.13 and 0.367 to 0.26. The two outermost s and p functions were then combined into two sp-type functions. The exponent of the outermost d-type function (exponent 0.15) increased to 0.20. The f-type polarization function was removed. The final basis set in CRYSTAL input format is as follows:

TZVP basis set for Os
The basis set was derived from the molecular Karlsruhe def2-TZVP basis set (60-electron effective core potential). [6] The diffuse outermost s-and p-type functions with exponents of 0.047 and 0.052 were removed. The exponent of the outermost p-type function was changed from 0.31 to 0.13 and it was combined with the outermost s function into a single sp-type function. The most diffuse d-type function (exponent 0.11) was removed and the inner (4d) function was decontracted to (3d1d). The f-type polarization function was removed. The final basis set in CRYSTAL input format is as follows:

Lattice parameters and atomic coordinates of the optimized solid-state structure of ClOF2[AsF6]
The initial parameters for the optimization were taken from a previous study on the crystal structure of ClOF 2 [AsF 6 ]. [2] Space group Pna2 1

Model 1 (full oxygen occupation on position O(1A))
Energy difference relative to Model 3: 6.6 kJ/mol

Lattice parameters and atomic coordinates of the optimized solid-state structures of ClOF2[NbF6] Model 2 (full oxygen occupation on position O(1B))
Energy difference relative to Model 3: 6.0 kJ/mol

Lattice parameters and atomic coordinates of the optimized solid-state structures of ClOF2[NbF6] Model 3 (full oxygen occupation on position O(1C))
Space group Pna2