Mason, W. R. (Professor of chemistry)
M.S. (Master of Science)
Department of Chemistry
This thesis describes the preparation and characterization of a number of alkyl phosphite complexes of platinum in the 0 and II oxidation states. The platinum(0) complexes investigated included [Pt(P(OCH₃)₃)₄], [Pt(P(OC₂H₅)₃)₄] and [Pt(ETPB)₄], while the platinum(II) complexes were [Pt(P(OH)(OC₂H₅)₂)₂(P(O)(OC₂H₅)₂)₂], [Pt(P(OH)(OCH₃)₂)₂(P(O)(OCH₃)₂)₂] and [Pt(P(OC₂H₅)₃)₄]-[ClO₄)₂]. The preparation of the platinum(O) complexes presented difficulties due to oxidation to platinum(II). Care must be taken to exclude oxygen during their preparation. Detailed synthetic procedures are described. proton nuclear magnetic resonance spectra are reported for [Pt(P(OC₂H₅)₃)₄] [Pt(P(OH)(OCH3)₂)₂- (P(O)(OCH₃)₂)₂], [Pt(P(OH)(OC₂H₅)₂)₂(P(O)(OC₂H₅)₂)₂] and [Pt(P(OC₂H₅)₃)₄][ClO4]₂ in CDCl₃ solutions using tetramethylsilane as a reference. In order to characterize a low field resonance assigned to the P-O-H, the two alkyl phosphite complexes [Pt(P(OH)(OR)₂)₂-(P(O)(OR)₂)₂] were titrated with CF₃COOH. The spectra are consistent with a structure involving bridging hydrogens between the phosphite and the phosphito ligands. The P-O-H proton was also exchanged with deuterium. Phosphorous-31 nuclear magnetic resonance spectra for these complexes are also reported as well as for [Pt(ETPB)₄] and [Au(ETPB)₄][ClO₄]; ³¹P NMR spectra of the ligands P(OCH₃)₃, P(OC₂H₅)₃ and ETPB are also included. All the ³¹P spectra were obtained for CDCl₃ solutions with H₃PO₄ as a reference. Ultraviolet electronic spectra were determined for [n̲-(C₄H₉)₄N]₂[Pt(CN)₄], [Pt(P(OC₂H₅)₃)₄][ClO₄]₂, [Pt(P(OH)(OC₂H₅)₂)₂(P(O)(OC₂H₅)₂)₂], [Pt(P(OH)(OCH₃)₂)₂-(P(O)(OCH₃)₂)₂], [Pt(ETPB)₄], [Pt(P(OC₂H₅)₃)₄] and [Pt(P(OCH₃)₃)₄] in 95% alcohol solutions and that of [Au(ETPB)₄][ClO₄] in CH₃CN. Intense charge-transfer bands are observed in the region between 3.0 - 5.0 μm-1 for the platinum(II) complexes. The platinum(O) complexes show strong absorptions above 4.5 μm-1; however, the spectra of a solution of [Pt(P(OC₂H₅)₃)₄] left standing in air changes smoothly as a function of time as it undergoes oxidation to [Pt(P(OH),(OC₂H₅)₂)₂(P(O)(OC₂H₅)₂)₂] revealing an isobestic point at 3.9 μm-1. The ultra-violet spectral features of the complexes are interpreted with the aid of simplified d⁸ and d¹⁰ molecular orbital diagrams, as metal to ligand charge transfer (MLCT) transitions. Magnetic circular dichroism (MCD) spectra were also obtained for [Pt(P(OC₂H₅)₃)₄][ClO₄]₂ and [Pt(P(OH)(OCH₃)₂)₂(P(O)(OCH₃)₂)₂] in CH₃CN solutions using a magnetic field of 7 T. The MCD spectral data are consistent with and are used to support the MLCT assignments of the UV spectra.
Solar G., Jose M., "Alkyl phosphite complexes of platinum" (1983). Graduate Research Theses & Dissertations. 1055.
xi, 72 pages
Northern Illinois University
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