Alkali Metal Cation Affinities of Anionic Main Group‐Element Hydrides Across the Periodic Table. Issue 19 (13th September 2017)

• Record Type: Journal Article
• Authors: Boughlala, Zakaria; Fonseca Guerra, Célia; Bickelhaupt, F. Matthias
• Is Part Of: Chemistry, an Asian journal. Volume 12:Issue 19(2017)
• Page Start: 2604
• Page End: 2611
• Publication Date: 2017-09-13
• Subjects: alkali metal cation affinities -- bond theory -- density functional calculations -- proton affinities -- thermochemistry; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/asia.201700956
• Languages: English
• ISSNs: 1861-4728

Abstract

Abstract: We have carried out an extensive exploration of gas‐phase alkali metal cation affinities (AMCA) of archetypal anionic bases across the periodic system using relativistic density functional theory at ZORA‐BP86/QZ4P//ZORA‐BP86/TZ2P. AMCA values of all bases were computed for the lithium, sodium, potassium, rubidium and cesium cations and compared with the corresponding proton affinities (PA). One purpose of this work is to provide an intrinsically consistent set of values of the 298 K AMCAs of all anionic (XH n ‐1 − ) constituted by main group‐element hydrides of groups 14–17 along the periods 2–6. In particular, we wish to establish the trend in affinity for a cation as the latter varies from proton to, and along, the alkali cations. Our main purpose is to understand these trends in terms of the underlying bonding mechanism using Kohn–Sham molecular orbital theory together with a quantitative bond energy decomposition analyses (EDA). Abstract : Diffuse and Different ! We have explored and analyzed alkali metal cation affinities (AMCA) of archetypal anionic bases with electrophilic centers across the periodic table. AMCAs are significantly weaker and show a number of different trends if compared to the corresponding proton affinities (PAs). Our bonding analyses trace the differences to the more diffuse nature and higher energy of the alkali cation n s LUMO as compared to the proton 1 s LUMO.