Abstract: Fluorone photometric reagent series have been studied with a computer program of PPPmethod for the electronic structures, and photometric properties of the organic reagents determined by experiments were compared with the calculated results and a good agreement was found. Some rules were presented by analyzing the calculated results. The conclusion indicated that substituent effects on the photometric properties of reagents and their metal complexes are not obvious.

Key words: Organic photometric reagents, Fluorone reagent series, PPP method