Mustafa Taştekin

Titrations in non-aqueous media: Conductimetric and spectrophotometric investigation of reactions between iodine and aliphatic amines in acetonitrile

Abstract The reactions between iodine and methyl-, ethyl-, n-propyl- and n-butylamines were investigated conductimetrically and spectrophotometrically in acetonitrile. The mole ratios of iodine to the amines titrated are 1:2, 2:2, 3:2 and 4:2, respectively, indicating strongly the formation of anionic species of the types I−, I−3, I−5 and I−7 and cationic species of the type [R3N-I-NR3]+. Although the conductivities of the primary amines do not show a regular order, the secondary and tertiary amines show orders at least at the first end-points. The order for secondary amines is Me2NH>Et2NH>n-Pr2NH>n-Bu2NH and for tertiary amines n-Bu3N>Et3N>Me3N. The end-points of the conductimetric titrations are fairly sharp and can be used in the determination of these amines.

Conductimetric and potentiometric titrations of phenolic acids with triethylamine and tetrabutylammonium hydroxide in acetonitrile

Abstract Nineteen phenolic acids, namely phenol, 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol, 2,6-dinitrophenol, 2,4,6-trinitrophenol, 4-chlorophenol, 2,4,6-trichlorophenol, 1,2-dihydroxybenzene, 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 1,2,3-trihydroxybenzene, 2-aminophenol, 3-aminophenol, 4-aminophenol, 3-cresol and 4-cresol, were titrated conductimetrically and potentiometrically with triethylamine and tetrabutylammonium hydroxide in acetonitrile under a nitrogen atmosphere at 25°C. Most exhibited normal behaviour on titration with triethylamine, but only 2,4-dinitrophenol, 2,6-dinitrophenol and 2,4,6-trinitrophenol gave useful characteristic and stoichiometric conductimetric titration curves. None of the compounds gave a meaningful conductimetric titration curve on titration with tetrabutylammonium hydroxide, which is a much stronger base than triethylamine. With three exceptions, all compounds exhibited stoichiometric well shaped potentiometric titration curves. Potentiometric titration curves of the phenolic acids with tetrabutylammonium hydroxide in acetonitrile are very similar to those of strong acids obtained in aqueous media with strong bases. Acetonitrile is a suitable solvent for titrating some of the weak phenolic acids conductimetrically with triethylamine, and is an excellent medium for titrating them potentiometrically with tetrabutylammonium hydroxide under a nitrogen atmosphere at 25°C.

The synthesis, structure and thermal decomposition of some Cu(II) complexes with NNN type ligands and thiocyanate anion

Three new complexes were prepared from Cu(II) thiocyanate and bis-2,6(pyrazol-1-yl) pyridine (pp), bis-2,6(3,5-dimethylpyrazol-1-yl) pyridine (dmpp) and 2-(3,5-dimethylpyrazol-1-yl)-6-(pyrazol-1-yl) pyridine (mpp). One of the complex structures was characterized using X-ray diffraction. Cu(II), within the N5 coordination sphere, was seen to form a square pyramid and trigonal bipyramid structure. Decomposition of the three complexes was analyzed thermogravimetrically. Results showed the complexes to be more stable with comparison to Cu(SCN)2.

Crystal structure and thermal analysis of new mononuclear nickel (II) complexes with NNN type pyrazolyl ligands and halids

Abstract Mononuclear Ni(II) complexes of Bis-2,6(pyrazolyl)pyridine(pp), 2(1-pyrazolyl)-6-(3,5-dimethylpyrazol-1-yl)pyridine(mpp) and bis-2,6(3,5-dimethyl-pyrazolyl-1yl)pyridine(dmpp) were prepared in MeOH : H2O mixtures. The complexes were characterized using elemental analysis, IR spectroscopy, X-ray diffraction and thermal analysis. The molecular structure of [Nidmpp(H2O)2Br]Br was evaluated and the Ni(II) ion was found to be in a distorted octahedral coordination environment. One of the halogen ions was found to coordinate the Ni(II) ion whereas the other ion does not coordinate and forms hydrogen bonds with the water molecules situated on the neighboring complex molecules, resulting in a supramolecular arrangement. Thermogravimetric results showed three coordinated water molecules in the pp and mpp complexes. Conductometric and potentiometric studies of the complexes showed 2 and 1 turning points, respectively.

Simultaneous determination of copper and zinc in brass samples by PCR and PLS1 methods using a multiple ion-selective electrode array

A method was developed to determine copper and zinc simultaneously in brass sample using a multiple ion-selective electrode array system and multivariate calibration techniques. The multiple ion-selective electrode array system was consisted of one pH electrode and eight ion selective electrodes which were formed using commercial ionophores and which are mainly sensitive copper and zinc. PCR, PLS1 which are multivariate calibration techniques were used to calibrate the multiple ion-selective electrode array system using five level multivariate calibration design and PCR method was selected as most suitable method. The measurements were performed at pH 10 in ammonia-ammonium chloride buffer. Copper and zinc content of a brass sample were determined by the calibrated multiple ion-selective electrode array system and the composition of brass sample was also determined by gravimetric method. The percentage amount of copper and zinc in brass sample were 64 ± 1 and 26 ± 2, respectively using the gravimetric method. The percentage results obtained in brass samples for copper and zinc were 63 ± 3 and 24 ± 3 by PCR method and 60 ± 5 and 20 ± 7 by PLS1 method, respectively. The obtained results were calculated for a 95% confidence level.

Determination of Heavy Metals in Almonds and Mistletoe as a Parasite Growing on the Almond Tree Using ICP-OES or ICP-MS

In this study, the elements of Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Ni, Sr, Pb, Ti, and Zn were determined in the leaves, fruits, and branches of mistletoe, (Viscum albüm L.), used as a medicinal plant, and in the leaves, branches and barks of almond tree which mistletoe grows on. The aim of the study is to investigate whether the mistletoe are more absorbent than the almond tree in terms of the heavy metal contents and the determination of the amount of the elements penetrated into the mistletoe from the almond tree. ICP-MS (inductively coupled plasma-mass spectrometry) was used for the analysis of As, Cd, Mo, and Pb, whereas ICP-OES (inductively coupled plasma optical emission spectrometry) was used for the other elements. The results obtained were statistically evaluated at 95% confidence level. Within the results obtained in this study, it was determined whether there is a significant difference between metal elements in almond tree and mistletoe, or not. As a result, it was observed that there were higher contents of B, Ba, K, Mg, and Zn in the mistletoe than in the almond tree. K was found much higher than other elements in the mistletoe. On the other hand, Al, As, Ca, Cd, Cr, Cu, Fe, Mo, Ni, Sr, Pb, and Ti contents were determined to be more in almond tree than mistletoe.