The paper reports an unprecedented spectrophotometric determination of amines in chloroform, in which amines are not transformed into colored derivatives. This result has been achieved by exploiting the acid−base properties of the tight-ionpaired metal complexes [(HR2DTO)Pt(H2R2DTO)][Cl], which are able to donate a HCl molecule to an amine, giving rise to an ammonium salt and to the neutral complexes [(HR2DTO)2Pt]. The circumstance that [(HR2DTO)Pt(H2R2DTO)][Cl] and [(HR2DTO)2Pt] species show different absorptions in the visible region of the electromagnetic spectrum enables the aforementioned platinum complexes to behave as self-indicating titrants in the spectrophotometric determination of aliphatic amines, which are known to be UV−vis transparent. The new method has been tested by determining a series of fatty amines in the bulk and gave excellent results. The limits of applicability of this method (pKa > 4) were found by testing a series of benzodiazepines.
Titolo: | Metal Complexes as Self-Indicating Titrants for Acid-Base Reactions in Chloroform |
Autori: | LANZA, Santo [Membro del Collaboration Group] |
Data di pubblicazione: | 2018 |
Rivista: | |
Abstract: | The paper reports an unprecedented spectrophotometric determination of amines in chloroform, in which amines are not transformed into colored derivatives. This result has been achieved by exploiting the acid−base properties of the tight-ionpaired metal complexes [(HR2DTO)Pt(H2R2DTO)][Cl], which are able to donate a HCl molecule to an amine, giving rise to an ammonium salt and to the neutral complexes [(HR2DTO)2Pt]. The circumstance that [(HR2DTO)Pt(H2R2DTO)][Cl] and [(HR2DTO)2Pt] species show different absorptions in the visible region of the electromagnetic spectrum enables the aforementioned platinum complexes to behave as self-indicating titrants in the spectrophotometric determination of aliphatic amines, which are known to be UV−vis transparent. The new method has been tested by determining a series of fatty amines in the bulk and gave excellent results. The limits of applicability of this method (pKa > 4) were found by testing a series of benzodiazepines. |
Handle: | http://hdl.handle.net/11570/3123469 |
Appare nelle tipologie: | 14.a.1 Articolo su rivista |