Synthesis and characterization of complexes involving phosphino-centres as Lewis acids.
Date
2001
Authors
Phillips, Andrew Douglas.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
Phosphines, where there is a lone pair of electrons on phosphorus, are typically regarded as Lewis bases, whereas hypervalent bonding environments with electronegative substituents are effective Lewis acids. The discovery of compounds with mono- and di-substituted phosphine centres, such as the phosphadiazonium cation Mes*NP+ (Mes* = 2,4,6-tri- tert-butylphenyl) and iminophosphines, RNPR', provide access to new phosphorus bonding environments. The complexes reported in this thesis represent the development of phosphines as Lewis acids.
A series of phosphadiazonium-ligand-triflate complexes [Mes*NP•Lg]OSO 2CF3, (Lg = Ligand), (A) have been isolated and comprehensively characterized. This involved a series of ligands having a range of basicities and polarizabilities (pyridine, 1-azabicyclo[2.2.2]-octane, imidazol-2-ylidene, tertiary phosphine chalcogenides and chalcogenoimidazolines). Spectroscopic and structural properties of these complexes are discussed in the context of data available for other established bonding environments of phosphorus. A complex (B) containing a chelated phosphine centre has been prepared and characterized using the bidentate 2,2' -dipyridyl ligand.
The synthesis of previously unknown P-functionalized iminophosphines (i.e., P-silyl-iminophosphines) was accomplished using Mes*NPOSO2CF3 as a Lewis acid. The Lewis acidic properties of P-chloro-iminophosphine (Mes*NPCl) have been demonstrated using imidazol-2-ylidene as a ligand affording a complex ( C) which represents a definitive example of an iminophosphide bonding environment. The adduct features a trisubstituted phosphorus centre with pyramidal geometry and P--N pi-bonding.*
*Please refer to dissertation for diagrams.
Thesis (Ph.D.)--Dalhousie University (Canada), 2001.
A series of phosphadiazonium-ligand-triflate complexes [Mes*NP•Lg]OSO 2CF3, (Lg = Ligand), (A) have been isolated and comprehensively characterized. This involved a series of ligands having a range of basicities and polarizabilities (pyridine, 1-azabicyclo[2.2.2]-octane, imidazol-2-ylidene, tertiary phosphine chalcogenides and chalcogenoimidazolines). Spectroscopic and structural properties of these complexes are discussed in the context of data available for other established bonding environments of phosphorus. A complex (B) containing a chelated phosphine centre has been prepared and characterized using the bidentate 2,2' -dipyridyl ligand.
The synthesis of previously unknown P-functionalized iminophosphines (i.e., P-silyl-iminophosphines) was accomplished using Mes*NPOSO2CF3 as a Lewis acid. The Lewis acidic properties of P-chloro-iminophosphine (Mes*NPCl) have been demonstrated using imidazol-2-ylidene as a ligand affording a complex ( C) which represents a definitive example of an iminophosphide bonding environment. The adduct features a trisubstituted phosphorus centre with pyramidal geometry and P--N pi-bonding.*
*Please refer to dissertation for diagrams.
Thesis (Ph.D.)--Dalhousie University (Canada), 2001.
Keywords
Chemistry, Inorganic.