The effects of axial ligation to meso-tetraphenylporphinatocadmium (CdTPP) were studied in dimethyl sulfoxide (DMSO) or dichloromethane (CH2Cl2). Addition of neutral (L) or anionic ligands (X-) to CdTPP caused red shifts in the absorption spectrum. The magnitude of the red shift depended on the charge but not on the strength of the Cdligand bond. Further, a relationship between the ratio εα/εβ and the wavenumber of the Soret band was observed.
