SPECTROPHOTOMETRİC STUDY of the Complex fORMATİON OF COPPER (II) WİTH 1-Phenyl-2- [2-Hydroxy-3-sulfo-5-nİtrophenylazo] 1,3- butadİONE İn the presence OF CATİONİC SURFACTANTS

Based on benzoylacetone synthesized 1-phenyl-2[2-hydroxy-3-sulfo-5-nitrophenylazo] 1,3-butadione (PHSNPAB). Studied complex formation of copper (II) with 1-phenyl-2[2-hydroxy-3-sulfo-5-nitrophenylazo] 1,3-butadione (PHSNPAB) in the presence and absence of the third component such as cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr) and cetyltrimethylammonium bromide (CTMABr). Single ligand complexes are formed at pH = 3, λ = 444nm, and mixed ligand complexes at pH = 2 λ = 456, 454, and 461 nm, respectively (CPCl, and CPBr, CTMABr). İdentified the relations of the reacting components in homogeneous composition of Cu-R (1: 2) and mixed ligand Cu-R-CPCl (1: 2: 2), Cu-R-CPBr (1: 2: 2) and Cu-R-CTMABr (1 2: 1) complexes, which concentration interval subordinated to Beer's law. The influence of external ions and masking substances on complex formation was studied. Method for the photometric determination of copper in the rocks was established.


İntroduction
Azo compounds are important, well-known and commonly used compounds in textile, paper industries and as dying agent in food and cosmetic industries. Azo compounds possess important analytic features, by providing a strong chromophore label-the quantity of which is determined by a colorimetric, spectrophotometric or spectrofluorometric methods. Additionally, azo compounds as have been reported show various biological activities, including antibacterial, antifungal, pesticides, antiviral and anti-inflammatory activities [1][2][3][4][5].
The purpose of the following work is the development of photometric determination method for identifying copper (II) with PHSNPAB in the presence and in the absence of the third component.

Experimental part
PHSNPAB synthesized as a result of azocoupling reaction of diazotized 2-amino-4-nitro-6-sulphophenol-1 with benzoylacetone in a weakly alkaline medium [9], and its composition and structure were established by IR and NMRspectroscopy.

RESULTS AND İTS DİSCUSSİON
The investigated complex compounds are formed immediately after mixing solutions. The ratio of the reactants in the complexes was found by method of isomolar series, the relative yield of Starika-Barbanel, equilibrium shift [11]. All methods showed that the ratio of Cu (II) -R in binary complexes is 1: 2, and in mixed-ligand complexes Cu (II)-R-CPCl = 1: 2: 2, Cu (II) -R-CPBr = 1 : 2: 2, Cu(II)-R-CTMABr = 1: 2: 1. The molar absorption coefficients of complexes were calculated from the saturation curves 11. Established concentration ranges where Beer's law is observed (Table 1).

Absorption spectra.
The study of complex formation depending on the acidity of the medium, showed that the maximum output of the complex CuR observed at pH 3 (max = 444nm), respectively. However, reagent in itself has a maximum absorbance at pH 2 (λmax = 461 nm) (   The effect of external ions and masking substances on the photometric determination of copper (II) in the form of binary and mixed-ligand complexes was studied. Relative selectivity of systems is shown in Table. 2.

The effect of pH and concentration of reactant.
The study of complex formation depending on pH (1)(2)(3)(4)(5)(6)(7)(8) showed that the yield of binary Cu-R complex is maximal at pH = 3. In the presence of a third component -CPCl, CPBr and CTMABr form intensely colored ternary compound CuR -CPCl, CuR -CPBr and CuR -CTMABr, that have the maximum yield at pH = 2. The influence of reactants concentrations on the complex formation was studied. It was established that the yield of the complex Cu-R was maximum at 8

The calibration graph.
Prepared a series of solutions containing 0,25-3,07mcg / ml (homo-ligand), 0,12-2,56 mcg / ml (mixed-ligand) Cu (II) complexes and their absorption measured at λopt=490 nm relative to a control experiment solution. Established concentration ranges where Beer's law is observed and the molar absorption coefficients of the complexes from saturation curves (11) (Tabl 1). From Table 1 it is clear that using our proposed mixed-ligand complexes, it is possible to determine very small microgram amounts of copper.

Calculation of the stability constants of complexes.
Calculated stability constants one and mixed-ligand complexes of copper (II). İn order to calculate the complex stability constants used method of intersection of curves [12]. The concentration of the complex was calculated from the expression

Determination of copper(II) in the rocks.
For the analysis, was taken three different mountain-pyrite rock samples containing altered quartz diorite. The content of copper (II) in the samples was determined by the photometric and atomic absorption methods (Table. 3).  5g of sample in a glassy carbon plate is dissolved in a mixture of 10 ml of 9 mL HF + HCl + 3 ml HNO3. The resulting paste is treated with 5-6 ml of HNO3 at 50-60 C till the complete distillation of HF. The resulting precipitate was dissolved in water, filtered to the flask 50 ml and diluted to the mark with water. By determining the copper (II) with photometric method aliquot part of the resulting solution is placed in 25 ml flask, added 2 ml of 110 -3 M R solution, 1 mL 110 -3 CTMABr solution and diluted with a solution till the mark pH 2. The absorption of the solutions was measured at 490 nm in a cuvette with l = 1 cm KFK-2 with respect to the blank test solution. The results of analysis are shown in Table 3. Table 3. The results of determination of copper in the rocks (%) (n = 5, P = 0.95)