Quinoline-8-selenol

A comparison of the behavior of a series of ligands in which one of the bonding atoms is replaced by another in the same group of the periodic table, helps in the understanding of the properties of these ligands and their metal chelates. For these reasons we have made a comparative study of the acid dissociation and certain metal chelate formation equilibria of 8-quino-linol, quinoline-8-thiol and quinoline-8-selenol by spectrophotometric and potentiometric techniques (Tables I and II),... 

Metal Ion 8 -Quinolinol Quinoline-8-Thiol (2) Quinoline - 8 -Selenol... 

Both quinoline-8-selenol and quinoline-8-thiol exist almost entirely in their zwitter ion forms in water. In 50% v/v dioxane-water (dielectric constant = 32), quinoline-8-selenol is still present entirely as the zwitter ion form, but quinoline-8-thiol, with its significantly lower K. in water, is probably largely in its neutral form in the 50% aqueous dioxane medium. 

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