<b>INTERACTION OF 2-(2'-HYDROXY)PHENYLBENZOTHIAZOLINE WITH SOME METAL IONS: DETERMINATION OF ITS DISSOCIATION CONSTANT IN AQUO-ORGANIC MEDIA</b>

Abstract

Potentiometric titrations were carried out with 2-(2'-hydroxy)phenyl benzothiazoline (HPBT) in various 50%v/v aquo-organic media (dioxan-water, acetone-water, methanol-water, and ethanol-water) and in different percentages of dioxan. The results indicated that the ligand is a monoprotic acid with pKa corresponding to the hydroxyl group. The pKa value of HPBT determined in various aquo-organic media followed the regular order of the reciprocal of dielectric constant. The solid metal complexes employing HPBT were synthesized and characterized. Spectral studies of these metal complexes [M(II) = Co, Ni, Cu and Zn] complexes indicated ring cleavage and formation of bis benzylidene disulphide (BBDS) during complex formation.

Synthesis, Characterization, Biological Activity and DNA Cleavage Studies on Tetrazole Imine Base and Their Metal Complexes - An Experimental and Theoretical Approach

“…The pH-metric titrations were carried out in 70% dioxan-water medium at 303 K and 0.1 M (KNO 3 ) ionic strength. The dissociation constant values were calculated using Irving-Rossotti titration technique [18][19][20][21][22][23][24][25]. From the titration data obtained, dissociation constants have been calculated from the linear plot of log (1n A )/ n A Vs pH (Fig 7).…”

Synthesis, Characterization, Structural Interpretation, Biological Activity and DNA Cleavage Studies of 3-acyl 2-(2’hydroxy-5-X phenyl) Benzothiazoline Cu (II) Complexes

“…22-25 A survey of literature reveals that aryl benzothiazolines when interact with metal ions to form solid complexes, various structural changes occur in ligands [14][15][16][17] . The studies on 2-(2'-hydroxy) phenyl benzothiazoline complexes revealed that in presence of Cu(II) metal ion the cleavage of thiazoline ring, subsequent schiff base formation through the transfer of proton from nitrogen to sulphur and then dissociation of same proton from sulphur and second proton from hydroxyl group of phenyl ring occurred enabling its copper complex formation [18] . In present study as the ring cleavage is hindered by acetyl group at ring nitrogen, in presence of metal ions under the conditions of metal complex formation, only one proton dissociation occurs and the benzothiazoline ring remain as such.…”

Synthesis, Characterization, Biological Activity and DNA Cleavage Studies on Tetrazole Imine Base and Their Metal Complexes - An Experimental and Theoretical Approach

“…The pH-metric titrations were carried out in 70% dioxan-water medium at 303 K and 0.1 M (KNO 3 ) ionic strength. The dissociation constant values were calculated using Irving-Rossotti titration technique [18][19][20][21][22][23][24][25]. From the titration data obtained, dissociation constants have been calculated from the linear plot of log (1-n A )/ n A Vs pH (Fig 7).…”