A combined NMR and DFT study of conformational dynamics in lanthanide complexes of macrocyclic DOTA-like ligands

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F17%3A10364260" target="_blank" >RIV/00216208:11310/17:10364260 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1039/c7cp05296k" target="_blank" >http://dx.doi.org/10.1039/c7cp05296k</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1039/c7cp05296k" target="_blank" >10.1039/c7cp05296k</a>

Jazyk výsledku

angličtina

Název v původním jazyce

A combined NMR and DFT study of conformational dynamics in lanthanide complexes of macrocyclic DOTA-like ligands

Popis výsledku v původním jazyce

The solution dynamics of the Eu(III) complexes of H(4)dota (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracarboxylic acid) and H(5)do3ap (1,4,7,10-tetraazacyclododecane-4,7,10-tris(carboxymethyl)-1-methylphosphonic acid, bound in both monoprotonated and fully deprotonated forms) were investigated by using a combination of NMR measurements and DFT calculations. In solution, an equilibrium between the square antiprismatic (SAP) and twisted-square antiprismatic isomers (TSAP) of these complexes is present. These two isomers interconvert by rotation of the pendant arms or inversion of the cyclen chelate rings. 1D EXSY NMR spectra were used to determine these exchange rates with unprecedented accuracy. It was found that the two processes occur at different rates. Additional variable-temperature measurements allowed determination of the corresponding activation parameters for the two processes. DFT calculations were then used to obtain mechanistic information at the molecular level. The results show that the cyclen inversion pathway involves stepwise inversion of the four chelate rings formed upon metal ion coordination. However, the arm rotation process may operate through a synchronous rotation of the pendant arms or a stepwise mechanism depending on the system. A mixed cluster-continuum approach was required to improve the agreement between experimental and calculated activation parameters for the arm rotation process. The obtained results will aid the design of MRI contrast agents. Furthermore, the methodology developed in this work can be further applied for the investigation of other dynamic paramagnetic systems, e.g. peptides with Ln(III) probes or natively paramagnetic metalloproteins.

Název v anglickém jazyce

A combined NMR and DFT study of conformational dynamics in lanthanide complexes of macrocyclic DOTA-like ligands

Popis výsledku anglicky

The solution dynamics of the Eu(III) complexes of H(4)dota (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetracarboxylic acid) and H(5)do3ap (1,4,7,10-tetraazacyclododecane-4,7,10-tris(carboxymethyl)-1-methylphosphonic acid, bound in both monoprotonated and fully deprotonated forms) were investigated by using a combination of NMR measurements and DFT calculations. In solution, an equilibrium between the square antiprismatic (SAP) and twisted-square antiprismatic isomers (TSAP) of these complexes is present. These two isomers interconvert by rotation of the pendant arms or inversion of the cyclen chelate rings. 1D EXSY NMR spectra were used to determine these exchange rates with unprecedented accuracy. It was found that the two processes occur at different rates. Additional variable-temperature measurements allowed determination of the corresponding activation parameters for the two processes. DFT calculations were then used to obtain mechanistic information at the molecular level. The results show that the cyclen inversion pathway involves stepwise inversion of the four chelate rings formed upon metal ion coordination. However, the arm rotation process may operate through a synchronous rotation of the pendant arms or a stepwise mechanism depending on the system. A mixed cluster-continuum approach was required to improve the agreement between experimental and calculated activation parameters for the arm rotation process. The obtained results will aid the design of MRI contrast agents. Furthermore, the methodology developed in this work can be further applied for the investigation of other dynamic paramagnetic systems, e.g. peptides with Ln(III) probes or natively paramagnetic metalloproteins.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10402 - Inorganic and nuclear chemistry

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physical Chemistry Chemical Physics

ISSN

1463-9076

e-ISSN

—

Svazek periodika

19

Číslo periodika v rámci svazku

39

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

10

Strana od-do

26662-26671

Kód UT WoS článku

000412763700019

EID výsledku v databázi Scopus

2-s2.0-85031328813