The PF_6−n(R)_n⁻anions (R = CH₃, C₂H₅;n= 0–6): the dependence of the electronic stability on the number of non-electronegative alkyl ligands

Abstract

C 2 H 5 ; n = 0-6): the dependence of the electronic stability on the number of non-electronegative alkyl ligands, The PF 6−n (R) n − superhalogen anions (where R = CH 3 , C 2 H 5 and n = 1-6) were investigated at the ab initio OVGF/6-311 ++ G(3df,3pd)//MP2/6-311 ++ G(d,p) level of theory and their electronic and thermodynamic stabilities were compared to those of the reference PF 6− system. It is demonstrated that (1) the presence of six substituents bound to the phosphorus atom is an important factor that enables the stability of the PF 6−n (R) n − anions;(2) subsequent replacement of the fluorine ligands with alkyl R groups in the PF 6 − superhalogen anion results in a substantial electronic stability decrease (by 2.38-6.74 eV); (3) when the certain number of alkyl substituents is achieved, the PF 6−n (R) n − anions become thermodynamically unstable.

Dihalides of Sterically Constrained Tricyclic Phosphines, Lewis Acidity and Fluoride Affinity, Chloride Abstraction, and a Phosphonium Cation, Dimethylphosphorane

“…electron withdrawing C 6 F 5 substituents and an imine or aldehyde group bound to their central P atoms . Similar compounds with alkyl or aryl groups bound to phosphorus are unknown, and quantum chemical calculations suggest that alkyl‐substituted species of that type are unstable with respect to the elimination of ethane and isobutane …”

Electron Propagator Theory of Vertical Electron Detachment Energies of Anions: Benchmarks and Applications to Nucleotides

“…The importance of electron correlation in determining reliable electron detachment energies of superhalide anions was emphasized at an early stage . Metal (M with m valence electrons) halide (X) anions with the general formula M i X mi +1 – that exhibit delocalization of Dyson orbitals over many halogen centers have been especially frequent objects of study. − Extensions to alternative electronegative ligands have been shown to be feasible. − Even organic ligands such as carboxylates and amino acids or fluoroborate tripods were discovered to be suitable for constructing superhalogens. − Connections between the search for more powerful superhalogens with record-setting electron detachment energies and the optimization of superacids with superlative Brønsted acidity have been identified after analysis of electron propagator calculations on icosahedral carboranes. , OF 3 – turns out to be a superhalogen, as do large H n F n +1 – clusters with extraordinarily large electron detachment energies, alkali-metal complexes with borane, HF–MF n – clusters, boron–nitrogen fluoride oligomers, NaCl clusters, noble-gas fluorides, BO 2 – , and (by a narrow margin) BS 2 – . Direct calculation of improvements to canonical Hartree–Fock energies has proven to be a crucial advantage in superhalide clusters where the qualifying electron detachment energy does not correspond to the highest occupied molecular orbital. − For example, in clusters with CN ligands, the order of σ and π orbitals may be reversed by electron correlation.…”