Phosphine and amine complexes of transition metals

McAvoy, James (1966) Phosphine and amine complexes of transition metals. PhD thesis, University of Glasgow.

Abstract

Amine complaxes for some first row Transition Metal perchlorates and tetrafluoroborates have been prepared, where the amines are pyridine, picoline and quinoline. The preparative procedure is comparatively simple. The desired salt was obtained by the reaction of the carbonate with either aqueous perchloric or tetrafluoroboric acids. Various methods have been employed for the preparation of the complexes. Thus, the ligand was added to an ethanolic solution of the salt hydrate, when, in some instances, the complex precipitated. Several now complexes have been prepared in this study. These are described by the general formula: LnE X2 where L= pyridins or picoline for n = 4. L = quinoline for n = 2. M = Mn, Co, Ni, Cu or Zn. X = perchlorate or fluoroborate. The stoichiorstries of the complexes are discussed, and their structure deduced in terms of the spectra in the near and for infra-red, and the reflectance spectra in the ultraviolet and visible regions. Where possible magnetic moments have been obtained, and are related to the proposed structures of the complexes. Perchlorate and tetrafluoroborate ions have Td symmetry Evidence is presented for some co-ordinate bond character between the anion and the metal. The effect of this on the symmetry of the anion is discussed. The stretching frequencies of the metal-nitrogen bond in the far infrared are interpreted in terms of the Irving-Williams order, and it is shown where relevant, that ring skeleral vibration also follow this sequence. The effect of ligand mass and basicity on the stereochemistry of the complexes is also discussed. The number of compounds known having phosphorus or nitrogen bonded to a metal, which in turn, is also bonded to fluorine, are relatively few. A method involving the use of liquid anhydrous hydrogen fluoride, has been found for the preparation of such compounds. The metals studied were confined to the second and third row Transition Elements, although attempts are described to extend the study to include some first row Transition Metals. Derivatives of the unknown platinum difluoride have been prepared in which the compound is stabilised by phosphine ligands. Some reactions of these complexes hare been investigated, and phosphino metal carbonyls obtained. Few carbonyl fluorides are known, and in general, they are difficult to prepare. In this study, several new carbonyl fluorides have been obtained in which the complexes are stabilized by the presence of phosphorus or nitrogen donor ligands. Examples of such compounds are:- (P(OPh)3)2 Pt(CO)2F2, (PPh3)2OS(CO)F3, Py2Mo(CO)2F2. Where Ph = phenyl and Py = pyridine. In these systems, hydrogen fluoride acts as an oridising agent. Thus, for example, tetrakis (triphenylphosphine) plantinum(O) is oxidised to bis(triphenylphosphine)platinum(11)fluoride, and tripyridinemolybdenum(O)tricarbonyl is oxidised to bispyridinedicarbonylmolybdenum(11)fluoride. The spectra of the complexes in the near infra-red are recorded, and the influence of the fluoride ion on the carbonyl stretching frequency is discussed. The reaction of liquid anhydrous hydrogen fluoride on tripyridinemolybdenumtricarbonyl gives, as a by-product, a complex analysing to a ton co-ordinate molybdenum (VI) species. Attempts have been made to investigate the extent of this co-ordination number in Group Via Metals, and some evidence is presented in support of the formulation.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: D WA Sharp
• Keywords: Inorganic chemistry
• Date of Award: 1966
• Depositing User: Enlighten Team
• Unique ID: glathesis:1966-72172
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 17 May 2019 12:40
• Last Modified: 17 May 2019 12:40
• URI: https://theses.gla.ac.uk/id/eprint/72172