Synthesis 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 23, 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 micro g 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