Variation of water exchange dynamics with ligand structure and stereochemistry in lanthanide complexes based on 1,4-diazepine derivatives.
Complexes of Gd, Eu and Yb(III) have been prepared with a series of heptadentate ligands related to the parent complex AAZTA, based on the 6-methyl-6-aminoperhydrodiazepine moiety. For (RR) and (RS)-diastereoisomers of a di-glutarate ligand, solution NMR studies revealed the presence of two major species that undergo water exchange rates at Gd differing by a factor of six. Comparison of solution hydration states for Eu(III) complexes reveals that each complex possesses two bound water molecules. The absence of a good correlation of (1)H NMR pseudo-contact shifts for Eu and Yb analogues is suggested to arise from a change in hydration state between Eu and Yb.
Elemento
Elisa M
EM
Department of Chemistry, Durham University, South Road, Durham, UK DH1 3LE.
Parker
David
D
Aime
Silvio
S
Gianolio
Eliana
E
Lattuada
Luciano
L
D001381:Azepines / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D001381:Azepines; D028581:Lanthanoid Series Elements; D008024:Ligands; D009942:Organometallic Compounds; D014867:Water