Department of Chemistry
Master of Science
The ultraviolet absorption spectra of a number of aryl phosphines and amines and transition metal complexes of triphenylphosphine have been determined. These data indicate that the intensity of the Õ* ¬ Õ phenyl ring transition is not only sensitive to the central atom attached to the ring but is also affected by the metal ion in the complex. Since the degree of covalency depends on the degree of back donation, the oxidation state of the metal ion was found to be the most important factor in determining the intensity of the absorption. The more covalent the metal-phosphine bond, the lower is the intensity of the Õ* ¬ Õ transition of the phenyl ring. The increase in the Õ* ¬ Õ absorption intensity can be explained in terms of a reduction of the phenyl ring symmetry from D6h to D2h or C2v.
Chen, Shing-Bong, "The Intensity of Ligand Absorption" (1973). Masters Theses & Specialist Projects. Paper 1018.