The coordination chemistry of phosphine ligands was pioneered by Mann, Chatt, and others beginning in the 1930s.1 Currently, phosphine compounds are sought as one of the most important classes of L-type ancillary ligands for transition metal complexes, particularly, because of their applications in a wide range of synthetically and catalytically valuable transition metal systems. There have been numerous efforts to understand the stereo-electronic properties of phosphine ligands and the nature of metal–phosphine bonding.2 Despite extensive effort in this field, there is considerably less known about the coordination chemistry of the 12-membered tri-phospha macrocycles due to the difficulty of their synthesis. This thesis describes a detailed study of the chemistry of 1,5,9-trialkyl-1,5,9-triphospha cyclododecane ([12]-ane-P3R3)3 ligands with copper, ruthenium, iron and cobalt metals. Chapter 1, reviews the background chemistry of this research. The radical-initiated coupling of three facially capping allylphosphine ligands on a neutral (CO)3Mo(0) template leads to the tri-secondary macrocycle, [12]-ane-P3H3 which then undergoes a two-step reaction involves deprotonation followed by alkylation. The macrocycle is then liberated from the template by oxidation of Mo, stereospecifically as the syn-syn isomer. The coordination chemistry of 12[ane]P3Et3, with copper(I) halides, is discussed in Chapter 2, including a bimetallic Cu(I) species with a unique mono bridging halide atom. All the complexes have been fully characterized analytically and structurally. Chapter 3 explores the coordination chemistry of triphosphacyclododecane ligands with Fe(0) and Co(0), which led to a range of novel macrocycle complexes, which have been characterised by multinuclear NMR, infrared spectroscopy, mass spectrometry and elemental analysis. Chapter 4 discusses a series of novel bimetallic and monometallic Ruthenium(II) complexes, which were isolated and characterised in the course of reactions with the macrocycle ligands. The catalytic ability of one such complex (4.9) with respect to ring closing metathesis of diethyl diallylmalonate is described. GC-MS data provide insight to support conclusions drawn about the RCM reaction.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:646319 |
| Date | January 2014 |
| Creators | Wickramatunga, Lenali Vinodangi |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/73251/ |
Page generated in 0.0016 seconds