Date of Award
Doctor of Philosophy
The synthesis and coordination chemistry of a fluorinated alkoxy-phosphino hybrid ligand is described. The fluorinated alcohol PH(,2)PCH(,2)C(CH(,3))(,2)OH,HL('1), is readily deprotonated in solution giving a bidentate, uninegative ligand, L('1) , containing both hard and soft donors, the alkoxide and phosphine respectively. Alternately the ligand in its protonated form, HL('1), can serve as monodentate phosphine ligand. The ligand coordinates, as a chelate, to both hard (Rh('3+), Co('2+), Ni('2+)) and soft (Cu('+), Pt('2+), Pd('2+), Pt('4+)) metals. In the case of platinum, a variety of complexes were prepared: cis- and trans- Pt(HL('1))(,2)Cl(,2) , Pt(L('1))(,2) , cis- and trans- Pt(HL('1))(L('1))Cl , Pt(PR(,3))(L('1))Cl (where PR(,3) = PPh(,3), PPh(,2)Me, PPhMe(,2), or PMe(,3)), Pt(HL('1))(L('1))CH(,3) and the Pt('4+) complex Pt(L('1))(,2)Cl(,2) . The preferred geometry of these complexes depends on a combination of electronic and steric factors and the latter factors were investigated further by two crystal structure determinations, those of trans- Pt(HL('1))(,2)Cl(,2) and cis- Pt(L('1))(,2) . The monodentate ligand HL('1) is sterically demanding because of the bulky fluorinated alcohol group. For this reason, a trans-geometry is preferred for Pt(HL('1))(,2)Cl(,2) . The steric interactions are lessened considerably for the bidentate ligand L('1) and as a result a geometry with cis-phosphines is preferred for Pt(L('1))(,2) , Pt(L('1))(,2)Cl(,2) , Pt(HL('1))(L('1))Cl and Pt(PR(,3))(L('1))Cl .;The palladium complex Pd(L('1))(,2) can be made to react with Pd(PhCN)(,2)Cl(,2) giving a chloro-bridged dimer, Pd(,2)(L('1))(,2)((mu)-Cl(,2) , which could then be cleaved with a variety of ligands, L' giving Pd(L')(L('1))Cl (L' = PR(,3), SMe(,2), py). A crystal structure determination of one such cleavage product, cis- Pd(PPh(,2)Me)(L('1))Cl , was carried out, and the results indicated that the fluorinated alkoxide has a greater cis-influence than a chloride ligand.;The complex Ni(L('1))(,2) exists in solution as a mixture of cis- and trans-isomers in a solvent- and temperature-dependent equilibrium. Thermodynamic data for this isomerization were determined using variable-temperature ('31)P NMR. Kinetic data were also determined and an intramolecular mechanism through a tetrahedral intermediate was proposed. The crystal structure of Ni(L('1))(,2) was also determined. The phosphino groups are trans-disposed in square-planar geometry, and a weak interaction between trifluoromethyl groups and the metal ion appears to be responsible for the colour change observed on crystallization.
Montgomery, Craig Duvall, "Studies On A Fluorinated Alkoxy-phosphino Ligand" (1986). Digitized Theses. 1555.