Interaction of dimethyltin(IV) and trimethyltin(IV) with dehydroacetic acid

Abstract

The interaction of trimethyltin(IV) and dimethyltin(IV) with dehydroacetic acid was investigated at 25 C and 0.1 M ionic strength in 20% dioxane -water mixture. The stepwise formation constants of the complexes formed in solution were calculated using the non-linear least-square program MINIQUAD-75. The concentration distribution of the various complex species was evaluated as a function of pH.

Speciation Studies of Diorganotin(IV) Complexes with 3,3‐Bis(1‐methylimidazol‐2‐yl)propionate—Displacement Reaction by DNA Constituents

“…The pK a of a coordinated water molecule is calculated [18] by $\begin{array}{c}p{K}_{\text{a}\mathrm{1}}=\log {\beta }_{\mathrm{1}\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{1}\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{0}}-\log {\beta }_{\mathrm{1}\mathrm{\hspace{0.17em}\hspace{0.17em}}\mathrm{1}\mathrm{\hspace{0.17em}\hspace{0.17em}}-\mathrm{1}}.\end{array}$ The calculated value is 4.77 and higher than that of water molecule coordinated to the free dimethyltin (IV) ion (3.39). This may be due to the elongation of the Sn(IV)-H 2 O bond caused by the coordination of 3,3-bis(1-methylimidazol-2-yl)propionate.…”

“…Therefore, there is a relationship between the stability of the organotin(IV) compounds and their antitumor activity. In conjunction with our previous studies on organotin (IV) complexes [ 18 – 22 ], the present paper aims to study dimethyl-, dibutyl-, and diphenyltin(IV) complexes with 3,3-bis(1-methylimidazol-2-yl)propionate (BIMP). The displacement reaction of coordinated (BIMP) by inosine and inosine-5′-monophosphate, taken as representative examples of DNA constituents, is investigated.…”

Formation of Fe(III) Ternary Complexes with Related Bio-relevant Ligands

“…Values of pK w in dioxane-water mixtures were determined as described previously [36,37]. Different amounts from NaOH of the known concentration were added to a solution of ionic strength 0.…”

Complex Formation Equilibria of Unusual Seven-Coordinate Fe(EDTA) Complexes with DNA Constituents and Related Bio-relevant Ligands

“…Values of pK w in dioxane-water mixtures were determined as described previously [17,18]. For this purpose, various amounts of standard NaOH solution …”