Steric and electronic control of low-coordinate pnictogen bonding.
Date
1998
Authors
Macdonald, Charles Lloyd Bergstrom.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
This work examines the concepts of steric and electronic stabilization and provides a rationale for their application to the structure and bonding of group 15 (Pnictogen) elements.
Synthetic and ab initio studies demonstrate that electronic factors determine the bonding of pnictogenium cations (group 15 carbenoids) and suggest that the dimerization of arsenium cations is a solid-state packing phenomenon. The contrasting cycloaddition reactivity of phosphenium and arsenium cations is explained. The 2,4,6-tris(trifluoromethyl)phenyl (Fmes) substituent is not suitable for the stabilization of pnictogenium cations.
Identical reactions involving the bulky 2,4,6-tri-tbutylphenyl (Mes*) and slightly smaller 2,6-diisopropylphenyl (Dip) ligands yield either trisaminopnictines, pnictazanes or iminoaminopnictines depending on the pnictogen atom. A steric scale of relative thermodynamic stability for the structure and bonding of compounds containing the N-Pn-N (Pn = P, As, Sb, Bi) moiety is formulated.
Study of the unprecedented dimerization of Mes*N=P-OSO2CF 3 yields a qualitative assessment of kinetic and thermodynamic effects of bulky substituents. Reagents that allow for the synthesis of compounds containing the [Mes*N=As] fragment are described. These will allow for the development of a new chapter of main group inorganic chemistry.1
1Please refer to dissertation for diagram.
Thesis (Ph.D.)--Dalhousie University (Canada), 1998.
Synthetic and ab initio studies demonstrate that electronic factors determine the bonding of pnictogenium cations (group 15 carbenoids) and suggest that the dimerization of arsenium cations is a solid-state packing phenomenon. The contrasting cycloaddition reactivity of phosphenium and arsenium cations is explained. The 2,4,6-tris(trifluoromethyl)phenyl (Fmes) substituent is not suitable for the stabilization of pnictogenium cations.
Identical reactions involving the bulky 2,4,6-tri-tbutylphenyl (Mes*) and slightly smaller 2,6-diisopropylphenyl (Dip) ligands yield either trisaminopnictines, pnictazanes or iminoaminopnictines depending on the pnictogen atom. A steric scale of relative thermodynamic stability for the structure and bonding of compounds containing the N-Pn-N (Pn = P, As, Sb, Bi) moiety is formulated.
Study of the unprecedented dimerization of Mes*N=P-OSO2CF 3 yields a qualitative assessment of kinetic and thermodynamic effects of bulky substituents. Reagents that allow for the synthesis of compounds containing the [Mes*N=As] fragment are described. These will allow for the development of a new chapter of main group inorganic chemistry.1
1Please refer to dissertation for diagram.
Thesis (Ph.D.)--Dalhousie University (Canada), 1998.
Keywords
Chemistry, Inorganic., Chemistry, Physical.