| Abstract: | The optical rotary dispersion (ORD) and circular dichroism (CD) spectra of the lanthanide(III) complexes of D-( - )-trans-1,2-cyclohexanediaminetetraacetic acid (D( - )CDTA) were obtained. These spectra were seen to vary form very simple to very complex. The element with an atomic number of 61, promethium, was omitted from this study because onle very small amounts of the element have ever been isolated; thus it was not available for investigation. An interesting relationship between the complexity of the circular dichroism spectra and the electronic configuration of the lanthanide(III) ions was observed. The simplest spectra were obtained for the complexes of La(III), Gd(III), and Lu(III); these ions have the f⁰, f⁷, and f¹⁴ configurations, respectively. The f⁰, f⁷, and f¹⁴ configurations are generally regarded as stable since they represent empty, half-filled, and filled arrangements, respectively. Low wavelengths were required to excite the first circular dichroic transitions of these three complexes. ... |
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