Sulfur-substituted uranyl stabilized by fluoride ligands: matrix preparation of U(O)(S)F2via oxidation of U(0) by SOF2

A neutral sulfur-substituted uranyl complex [U(O)(S)F2] in which the SUO2+ moiety is stabilized by electron withdrawing fluoride ligands was prepared via oxidation of U(0) by SOF2 in cryogenic matrixes.

Decomposition of d- and f-Shell Contributions to Uranium Bonding from the Quantum Theory of Atoms in Molecules: Application to Uranium and Uranyl Halides

The electronic structures of a series of uranium hexahalide and uranyl tetrahalide complexes were simulated at the density functional theoretical (DFT) level. The resulting electronic structures were analyzed using a novel application of the Quantum Theory of Atoms in Molecules (QTAIM) by exploiting the high symmetry of the complexes to determine 5f- and 6d-shell contributions to bonding via symmetry arguments. This analysis revealed fluoride ligation to result in strong bonds with a significant covalent character while ligation by chloride and bromide species resulted in more ionic interactions with little differentiation between the ligands. Fluoride ligands were also found to be most capable of perturbing an existing electronic structure. 5f contributions to overlap-driven covalency were found to be larger than 6d contributions for all interactions in all complexes studied while degeneracy-driven covalent contributions showed significantly greater variation. σ-contributions to degeneracy-driven covalency were found to be consistently larger than those of individual π-components while the total π-contribution was, in some cases, larger. Strong correlations were found between overlap-driven covalent bond contributions, U–O vibrational frequencies, and energetic stability, which indicates that overlap-driven covalency leads to bond stabilization in these complexes and that uranyl vibrational frequencies can be used to quantitatively probe equatorial bond covalency. For uranium hexahalides, degeneracy-driven covalency was found to anti-correlate with bond stability.

Self-complementary nickel halides enable multifaceted comparisons of intermolecular halogen bonds: fluoride ligands vs. other halides

Studies of X–Ni–C6F4I⋯X–Ni–C6F4I halogen-bonded networks reveal pronounced differences between fluoride (X = F) and other halides: the 19F-MAS NMR spectrum is a sensitive probe of the halogen bond.

Chromium chains as polydentate fluoride ligands for actinides and group IV metals

New heterometallic rings containing Cr(iii) and tetravalent metals are reported, including a {Cr6Th2} cage.

Solid State Structure of Bis[(bromo)(dicyclopentadienyl)vanadium(μ2-fluoro)][(bromo)(cyclopentadienyl)vanadium][tetrafluoroborate]

The new complex [V(C5H5)2Br]2(μ2-F)2[V(C5H5)Br]+[BF4]− has been isolated from the reaction of vanadocene monobromide with the ferrocenium cation. The complex is a mixed valence compound composed of two V(IV) and one V(III) centers. The V(III) center has one cyclopentadienyl ligand in its coordination sphere, as well as a bromide and two fluoride ligands. Each fluoride ligand is also attached to one of the V(IV) centers, which additionally is coordinated by a bromide and two cyclopentadienyl ligands. The complex crystallizes in the monoclinic space group P21/m, with a=7.66490(10) Å, b=15.2457(2) Å, c=13.3185(2) Å, and β=101.2721(8)° at 150(1) K.

Crystal structure of a dinuclear CoIIcomplex with bridging fluoride ligands: di-μ-fluorido-bis{tris[(6-methylpyridin-2-yl)methyl]amine}dicobalt(II) bis(tetrafluoridoborate)

Reaction of Co(BF4)2·6H2O with tris[(6-methylpyridin-2-yl)methyl]amiine in methanol results in a fluoride abstraction from BF4−, yielding the unexpected title compound, [Co2F2(C21H24N4)2](BF4)2. The complex cation consists of two inversion-related [Co(C21H24N4)]2+moieties bridged by a pair of fluoride ligands. The CoIIcation is six-coordinated in a distorted octahedral geometry and forms a +II high-spin state. In the crystal, the complex cation and the BF4−anion are connected by C—H...F hydrogen bonds, forming a three-dimensional network. An intramolecular C—H...F hydrogen bond is also observed.