"Synthsis of 6-(2-naphthyl)-2,3-dihydro-as-triazine-3-thione as a Sensitive Reagent for the Spectrophotometric determination of Cu (II) "

Abstract

A Spectrophotometric method for determination of Cu (II) based on the complex formation with a new reagent 6-(2-naphthyl)-2,3-dihydro-as-triazine-3-thione(NDTT) is described. NDTT was synthesized based on the knowledge available for the preparation of 6-phenyl-2,3-dihydro-as-triazine-3-thione (PDTT). Reaction of 2-acetylnaphthalene 1 with amyl nitrite gave 2-naphthylglyoxal aldoxime 2, which upon reaction with thiosemicarbazide yielded 6-(2-naphthyl)-2,3-dihydro-as-triazine-3-thione (NDTT) 3.
NDTT produces a red complex with copper which is easily extractable with chloroform at pH>8 while the reagent is not extracted under these conditions. The absorption of the complex in the UV region (313 nm) is about 7 times greater than in the visible region (508 nm). The mole ratio of the complex which is formed between Cu (II) and NDTT is 2:3, which was calculated by both the mole ratio and the continuous variation methods. The absorbance of the complex obeys Beer’s law in the concentration range of 0.08-2 µg Cu(II)/ml chloroform with r = 0.998 and detection limit of 13 ng/ml. This procedure can be carried out in the presence of many cations and anions in the presence or absence of the masking agents.