Determination of the stability constants of the proton AND Co(II), Ni(II), Cu(II), Zn(II), Fe(III) COMPLEXES of 3,5-dimethyl tetrahydro-1,3,5-thiadiazine-2-thione by the potentiometric method

ERÇAĞ, Ayşe; TURAK, Fatma; ÖZGÜR, Mahmure; BOZDOĞAN, Abdürrezzak

Determination of the stability constants of the proton AND Co(II), Ni(II), Cu(II), Zn(II), Fe(III) COMPLEXES of 3,5-dimethyl tetrahydro-1,3,5-thiadiazine-2-thione by the potentiometric method

Ayşe ERÇAĞ ¹ , Fatma TURAK ² , Mahmure ÖZGÜR ² , Abdürrezzak BOZDOĞAN ²

¹
²

Sigma J Eng Nat Sci 2007; 25(4): 359-366

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Abstract

Dazomet (DTTT), (tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione) is soil fumigant used to control
weeds, soil fungicide, insects and nematodes. DTTT was synthesized and purified according to literature. The protonation constant of DTTT in water-ethanol 70:30(v%) solution was determined by potentiometric
titration at constant temperature, t = (25±0.10C) and 0.06 M NaClO4 as ionic background. The formation
constants of DTTT with Cu(II), Ni(II), Co(II), Zn(II), and Fe(III) were determined at the same conditions.
Purified nitrogen gas bubbled through the titrated solution to ensure stirring and neutral inert atmosphere. Furthermore, the solution was stirred magnetically. The solutions were titrated with 5.10-3 M NaOH in increments of 0.1 mL. The corresponding change in the pH value of the solution was measured. The stochiometric protonation constants of the ligand were calculated using software called TITFIT developed by Zuberbühler and Kaden(1). The formation constant of DTTT complexes with Cu(II), Ni(II), Co(II), Zn(II), Fe(III) and species distribution curves were calculated and plotted using TITFIT computer program. The values of the protonation constants for the ligand are log β1 = 9.49 (Δ=2.36.10-2) and log β2= 13.50 (Δ=2.38.10-2). The order of the stability constants of ML complexes with DTTT is Fe>Cu>Co>Ni>Zn and that of MLH complexes is Co>Cu>Fe>Ni>Zn.

Keywords: Dazomet, pesticide, stabilite constants, potentiometric method , TITFIT programme.

3,5-dimetil tetrahidro-1,3,5-tiyadiazin 2-tiyon’un protonasyon sabiti ve Co(II), Ni(II), Cu(II), Zn(II), Fe(III) komplekslerinin kararlılık sabitlerinin potansiyometrik yöntemle belirlenmesi

Ayşe ERÇAĞ¹ , Fatma TURAK² , Mahmure ÖZGÜR² , Abdürrezzak BOZDOĞAN²

¹İstanbul Üniversitesi, Mühendislik Fakültesi, Kimya Bölümü, Avcılar-İSTANBUL
²Yıldız Teknik Üniversitesi, Fen-Edebiyat Fakültesi, Kimya Bölümü, Esenler-İSTANBUL

Sigma Journal of Engineering and Natural Sciences 2007; 4(25): 359-366

Dazomet (DTTT); 3,5-Dimetil tetrahidro-1,3,5-tiyadiazin (2) tiyon yabani otları, toprak mantarlarını,
böcekleri ve kurtları kontrol etmek için kullanılan bir toprak fumigantıdır. Çalışmamızda DTTT laboratuarda
sentez edilerek saflaştırıldı. DTTT’nin protonlanma sabiti ve bazı metal iyonları ile verdiği komplekslerin
oluşum sabitleri su:etanol 70:30 (%h) ortamında potansiyometrik yöntem ile tayin edildi. Deneysel çalışmalar, potansiyometrik titrasyon hücresinde 25±0.10C’de inert azot atmosferinde kombine cam elektrod kullanılarak 0.06 M NaClO4’lu ortamda yapıldı. Her 0.1 mL baz (5.10-3 M NaOH) ilavesinden sonra pH değerleri okundu. Titrasyon verilerinden TITFIT bilgisayar programı kullanılarak DTTT’nin protonasyon sabiti ve metal komplekslerine ait oluşum sabitleri hesaplandı. Ligandın protonasyon sabitleri sırasıyla log β1 = 9.49 (Δ=2.36.10-2) log β2= 13.50 (Δ=2.38.10-2) olarak bulundu. Ayrıca DTTT’nin Cu(II), Ni(II), Co(II), Zn(II) ve Fe(III) ile verdiği ML komplekslerine ait oluşum sabitleri TITFIT programı ile bulunan sonuçlara göre Fe>Cu>Co>Ni>Zn’dur. MLH komplekslerine ait oluşum sabitleri ise Co>Cu>Fe>Ni>Zn’dir.

Anahtar Kelimeler: Dazomet, pestisid, stabilite sabiti, potansiyometrik yöntem, TITFIT program.