Divalent E(0) Compounds (E=Si–Sn)

Abstract

Quantum-chemical calculations at the BP86/TZVPP level of theory have been carried out for compounds EL(2) for E = Si, Ge, Sn, where L is a five-membered cyclic ylidene or N-heterocyclic ylidene. The theoretical results provide evidence for the classification of the complexes as divalent E(0) compounds, where the bonding situation is best described in terms of donor-acceptor interactions between a bare atom E, which retains its valence electrons as two lone pairs, and two donor ligands L --> E <-- L. The molecules are very strong donors, which may bind one or two Lewis acids. Divalent E(0) compounds have unusually high second proton affinities and they are strong sigma donor ligands. The calculations predict that complexes of EL(2) with one or two BH(3) ligands are stable enough to become isolated in a condensed phase. It is also shown that the bond dissociation energies (BDEs) of transition-metal complexes [(CO)(5)WD] and [(CO)(3)NiD], where D = EL(2) are rather high. The BDE of some ligands D are higher than those of CO in the metal carbonyls.

Recent Advances in the Field of Main‐Group Mono‐ and Diatomic “Allotropes” Stabilised by Neutral Ligands

“…[30] Frenking has examined the properties of the as-yet-unknown NHC (14 E)-and phosphine (15 E)-stabilised E 1 complexes for E = Si-Pb. [13,31] The results revealed that in all cases two distinct lone pair orbitals are found about the E centres (Figure 7), and the L À E bonding is consistent with a "dative" (donor-acceptor) description. Both lone pairs were predicted to be chemically accessible for these species, as is Scheme 2.…”

Understanding the structure of salicyl hydrazone metallocomplexes: crystal structure, AIM and Hirshfeld surface analysis of trichloro-(N-salicylidenebenzoylhydrazinato-N,O,O′)-tin(IV)

“…Nevertheless, a number of charge density studies of tin complexes are limited by compounds containing low-valent and multipole bonded tin (see Refs. [16,17] for instance) or analysis of HOMO and LUMO in tin complexes [18]. Besides, the chemical bonding in the donor-acceptor complexes of SnCl 4 and SnBr 4 was studied and the energies of some Sn-O and Sn-N bonds were estimated [19,20].…”

Bildung eines homoatomaren, polycyclischen Bismut‐Polyanions, [Bi11]3−, durch Pyridin‐unterstützte Zersetzung von [GaBi3]2−

“…[32] Die Frage, ob die um zwei Elektronen reichere Spezies auch stabil wäre, lässt sich vor dem Hintergrund umfassender quantenchemischer Untersuchungen von Frenking und Mitarbeitern positiv beantworten, die vorschlugen, dass die zu D isoelektronische Carbodicarben-Familie mit formal nullwertigem Kohlenstoff stabil sein sollte, [33] was kurz darauf durch erste Synthesen von Bertrand und Mitarbeitern bestätigt wurde. [34] In der Zwischenzeit wurden sowohl theoretische [35] als auch experimentelle [36] Arbeiten mit qualitativ identischen Ergebnissen auf die schwereren Tetrel(0)-Homologe erweitert -erstere auch auf die negativ geladenen Analoga der Gruppe 13, allerdings mit Imidazolium-basierten NHCs. Unsere Ergebnisse deuten darauf hin, dass solche Spezies auch experimentell zugänglich sein kçnnten.…”