Geometry of simple molecules. 2. Modeling the geometry of AX3E and AX2E2 molecules through the nonbonded interaction (NBI) model

Reactivity of Binary and Ternary Sulfur Halides towards Transition-Metal Compounds

Binary sulfur fluorides exhibit an interesting reactivity towards transition metal complexes. They open up routes for the generation of sulfur‐containing building blocks. Often ligands with particular properties can be constructed. This includes their ability to transfer sulfur atoms or polysulfide units as well as fluorination reactions. This Minireview provides an insight into the reactivity of the binary and ternary sulfur halides S₂Cl₂, SCl₂, SF₄, SF₆ and SF₅Cl towards transition‐metal compounds.

On the Significance of Lone Pair/Lone Pair and Lone Pair/Bond Pair Repulsions in the Cation Affinity and Lewis Acid/Lewis Base Interactions

Interaction of H₂O, H₂S, H₂Se, NH₃, PH₃, and AsH₃ with cations H⁺, CH₃ ⁺, Cu⁺, Al⁺, Li⁺, Na⁺, and K⁺ was studied from the energetic and structural viewpoint using B3LYP/6-311++G(d,p) method. The charge transfer from the Lewis bases to the cations reduces lone pair/lone pair (LP/LP) repulsion in H₂O, H₂S, and H₂Se and LP/bond pair (LP/BP) repulsion in NH₃, PH₃, and AsH₃. In parallel, changes in the H-M-H angles (M = O, S, Se, N, P, and As) are observed. The change in the H-M-H angle during the interactions was proportional to the amount of charge transferred from the bases to the cations and electron density (ρ) at the molecule/cation bond critical point. Also, the opposite trend for proton affinities of these two families, that is, NH₃ > PH₃ > AsH₃ and H₂O < H₂S < H₂Se, was interpreted on the basis of LP/BP repulsion in their neutral and protonated forms. Interaction of the Lewis bases with neutral Lewis acids including BeH₂, BeF₂, and BH₃ was studied energetically and structurally. The calculated energies for interactions of H₂O and NH₃ with BeH₂, BeF₂, and BH₃ are larger than the corresponding values for H₂S, H₂Se, PH₃, and AsH₃. This difference was interpreted on the basis of the lower stability of H₂O and NH₃ because of large LP/LP and LP/BP repulsion in H₂O and LP/BP repulsion in NH₃.