Analyzing Lanthanide-Induced Shifts in the NMR Spectra of Lanthanide(III) Complexes Derived from 1,4,7,10-Tetrakis(N,N-diethylacetamido)-1,4,7,10-tetraazacyclododecane

Analysis of lanthanide induced NMR shifts using a crystal field independent method: application to complexes of tetraazamacrocyclic ligands

“…1(B), which schematically represents part of the structure of the complexes in the D(llll) enantiomeric form of the M isomer, where H 5 denotes the pro-R and H 6 the pro-S pendant arm methylene proton. This notation is in agreement with work for the [Ln(DOTA)] ( complexes [31,32] [26,35]. Therefore, some reassignments were made in this work relative to the literature.…”

“…2(A) for some examples). As reported before [26,32,35], many of such plots do not follow a good single linear correlation but rather divide in two subgroups with a break between light and heavy lanthanide ions. The linear correlation coefficient R 2 and the values of F a and A 2 0 r 2 G a were evaluated for each proton and 13 C/ 31 P nucleus using those equations by subdivision of the lanthanides into two subgroups (Ce Ã/Eu and Tb Ã/Yb) and without such a subdivision (Ce Ã/Yb).…”

“…1 H, 13 3 CN at 253 K were also reported (the 13 C LIS data are available only for Pr, Nd, Sm and Eu complexes) [35]. All the above referred, previously published, LIS data analyzed in this work are listed in Table 1S.…”

“…Only one set of NMR signals was found in solution for the [Ln(DOTEA)] 3' complexes [35]. Analysis of the observed LIS values led to a solution structure of these complexes of the CSAP (M) type, with a twist angle of 478 between the planes of the O 4 and N 4 atoms.…”

“…The numbering scheme for hydrogen and carbon/ phosphorous atoms is also shown. H 5 denotes the pro-R and H 6 the pro-S pendant arm methylene proton (this notation has not always been followed [26,35]). enantiomeric conformations, given as dddd and llll (with respect to each five-membered ring chelate), and the pendant arms may be arranged in either a clockwise (D) or counterclockwise (L) manner, leading to four possible stereoisomers.…”