Concept

Aminopolycarboxylic acid

An aminopolycarboxylic acid (sometimes abbreviated APCA) is a chemical compound containing one or more nitrogen atoms connected through carbon atoms to two or more carboxyl groups. Aminopolycarboxylates that have lost acidic protons form strong complexes with metal ions. This property makes aminopolycarboxylic acids useful complexone in a wide variety of chemical, medical, and environmental applications. The parent of this family of ligands is the amino acid glycine, H2NCH2COOH, in which the amino group, NH2, is separated from the carboxyl group, COOH by a single methylene group, CH2. When the carboxyl group is deprotonated the glycinate ion can function as a bidentate ligand, binding the metal centre through the nitrogen and one of two carboxylate oxygen atoms, to form chelate complexes of metal ions. Replacement of a hydrogen atom on the nitrogen of glycine by another acetate residue, –CH2COOH gives iminodiacetic acid, IDA, which is a tridentate ligand. Further substitution gives nitrilotriacetic acid, NTA, which is a tetradentate ligand. These compounds can be described as aminopolycarboxylates. Related ligands can be derived from other amino acids other than glycine, notably aspartic acid. Higher density is achieved by linking two or more glycinate or IDA units together. EDTA contains two IDA units with the nitrogen atoms linked by two methylene groups and is hexadentate. DTPA has two CH2CH2 bridges linking three nitrogen atoms and is octadentate. TTHA has ten potential donor atoms. The chelating properties of aminopolycarboxylates can be engineered by varying the groups linking the nitrogen atoms so as to increase selectivity for a particular metal ion. The number of carbon atoms between the nitrogen and carboxyl group can also be varied and substituents can be placed on these carbon atoms. Altogether this allows for a vast range of possibilities. Fura-2 is noteworthy as it combines two functionalities: it has high selectivity for calcium over magnesium and it has a substituent which makes the complex fluorescent when it binds calcium.

À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.
Séances de cours associées (1)
Publications associées (35)

Electro- and photochemical H-2 generation by Co(ii) polypyridyl-based catalysts bearing ortho-substituted pyridines

Rosario Scopelliti, Euro Solari, Albert Ruggi, Vincent Artero, Fiorella Lucarini

Cobalt(II) complexes featuring hexadentate amino-pyridyl ligands have been recently discovered as highly active catalysts for the Hydrogen Evolution Reaction (HER), whose high performance arises from the possibility of assisting proton transfer processes v ...
ROYAL SOC CHEMISTRY2023

Insight into the Growth of Anisotropic CdSe Nanocrystals: Attachment of Intrinsically Different Building Blocks

Martinus Gijs, Virendra Kumar Parashar, Xiaopeng Huang

An in-depth understanding of the growth mechanism of nanocrystals (NCs) is of great significance for shape control of colloidal semiconductor nanostructures. In this study, we elucidate the formation mechanism of anisotropic CdSe NCs by systematically inve ...
AMER CHEMICAL SOC2020

Optical absorption properties of metal-organic frameworks: solid stateversusmolecular perspective

Berend Smit, Ivano Tavernelli, Maria Fumanal Quintana

The vast chemical space of metal and ligand combinations in Transition Metal Complexes (TMCs) gives rise to a rich variety of electronic excited states with local and non-local character such as intra-ligand (IL), metal-centered (MC), metal-to-ligand (MLCT ...
2020
Afficher plus
Concepts associés (4)
Stability constants of complexes
In coordination chemistry, a stability constant (also called formation constant or binding constant) is an equilibrium constant for the formation of a complex in solution. It is a measure of the strength of the interaction between the reagents that come together to form the complex. There are two main kinds of complex: compounds formed by the interaction of a metal ion with a ligand and supramolecular complexes, such as host–guest complexes and complexes of anions.
EDTA
L’EDTA (Éthylènediaminetétraacétique), ou acide éthylènediaminetétraacétique, est un acide diaminotétracarboxylique de formule . L'EDTA comporte six sites basiques, quatre correspondant aux bases conjuguées (carboxylates) des fonctions carboxyliques et deux correspondant aux fonctions amines. Ces sites basiques sont également des sites de complexation, faisant de l'EDTA un ligand hexadentate (ou parfois tétradentate, lorsque seuls les sites carboxyliques sont utilisés).
Ligand (chimie)
Un ligand est un atome, un ion ou une molécule portant des groupes fonctionnels lui permettant de se lier à un ou plusieurs atomes ou ions centraux. Le terme de ligand est le plus souvent utilisé en chimie de coordination et en chimie organométallique (branches de la chimie inorganique). L'interaction métal/ligand est du type acide de Lewis/base de Lewis. La liaison ainsi formée est nommée « liaison covalente de coordination ».
Afficher plus

Graph Chatbot

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.