UBC Theses and Dissertations
Luminescence and absorption spectra of some d6 complexes Mingardi, Maurizio Antonio Pietro
A systematic study has been done on the absorption and luminescence spectra of transition metal complexes with low-spin electronic configuration d⁶, in order to clarify the spectroscopic behavior of these complexes. The spectra have been measured in solutions and crystals at temperatures between 4 K and room temperature. The lifetimes of the luminescence were measured, too, as an aid to the assignments of the bands. Suitable equipment has been designed and assembled for these measurements. The series of transition metal complexes with different metal atoms and ligands was chosen in order to cover a large range of ligand field strengths and bonding characteristics. Some complexes of Co(lll), Ru(ll), Rh(lll), Os(ll), Ir(lll) and Pt(lV) have been found to luminesce. Other complexes have been investigated and even the absence of luminescence was important for the general understanding of the phenomenon. The results of this investigation show that for the complexes here studied the luminescence originates from the electronic transition ³T₁g, ↦ ¹A₁g , i.e. a transition of d-d type. Also, a luminescence of charge-transfer type has been reported in the literature for some d⁶ complexes. From our data and from the information already-available, some empirical rules were formulated for the luminescence of d⁶ low-spin complexes. A priori use of these rules enables us to prognosticate the presence and the characteristics of the luminescence of other d⁶, low-spin complexes.
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