The Crystal Structures of ClF3O, BrF3O, and [NO]+[BrF4O]−

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)

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 MV 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.

A rare example of a krypton difluoride coordination compound: [BrOF2][AsF6] x 2 KrF2

The synthesis of [BrOF(2)][AsF(6)] x 2 KrF(2), its structural characterization, and bonding are described in this study. Although several KrF(2) adducts with transition metal centers have been previously reported, none have been crystallographically characterized. The solid-state Raman spectrum of [BrOF(2)][AsF(6)] x 2 KrF(2) has been assigned with the aid of quantum-chemical calculations. The low-temperature (-173 degrees C) X-ray crystal structure of [BrOF(2)][AsF(6)] x 2 KrF(2) consists of isolated molecular units and represents an example of KrF(2) coordinated to a main-group atom. The coordination geometry around the BrOF(2)(+) cation renders the free valence electron lone pair more compact than in free BrOF(2)(+). The KrF(2) ligands are coordinated trans to the fluorine atoms of BrOF(2)(+) with the AsF(6)(-) anion coordinated trans to oxygen. The quantum theory of atoms in molecules (QTAIM) and electron localization function (ELF) analyses have been carried out in order to define the nature of the bonding in the complex. A significant amount of charge (0.25 e) is transferred to BrOF(2)(+) from the two KrF(2) ligands (0.10 e each) and from the AsF(6)(-) anion (0.05 e). Significant polarization also occurs within the KrF(2) ligands, which enhances the anionic characters of the fluorine bridges. The interaction energy is mostly governed by the electrostatic interaction of the positively charged bromine atom with the surrounding fluorine atoms.