A simple method for simulating lanthanide induced shifts in bifunctional substrates.
β Scribed by Antonino Recca; Paolo Finocchiaro
- Publisher
- Elsevier Science
- Year
- 1974
- Tongue
- French
- Weight
- 231 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0040-4039
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β¦ Synopsis
Recently we reported a simple topological approach to the computer simulation of Lanthanide Induced Shifts (LIS) in some substrates containing a carbonyl group:
This approach revealed that the Lanthanide complexed with the substrate only in certain preferred positions. More importantly,the results threw some light on the factors that influence the equilibria of confonnationally mobile systems when cost plexed with Lanthanide Shift Reagents (LSR).l Furthermore,we predicted that this simple approach could be readily extended to become a very convenient way to ana_ lyre the general problem,still unsolved,of the interaction of LSR with bi-and poly-functional substrates. 132
We now wish to report some preliminary results which show the reliability and utility of this approach to the interaction of LSR with bifunctional substrates.
π SIMILAR VOLUMES
By observing the shifts of the 'H NMR signals of 1,4-benzoquinones induced by Eu(fod),, and simulating them with the aid of a novel computer program TWOCEN, it has been shown that the two carbonyl groups of 1,4-toluquinone and 2,6-dimethyl-1,4-benzoquinoue compete in the Eu coordination. The metal b
It is generally accepted l-9 that chemical shifts induced by lanthanide shift reagents are predominantly or entirely due to a dipolar shielding mechanism. Assuming axial symmetry lo the dipolar shifts Ai are given by the McConnell-Robertson equation (1)11 where C is a proportion-Ai = C(I -3cos2ei)/R
## Abstract The ^13^C and ^1^H spectra of a series of aromatic ketones, ethers and ketoβethers were studied using the lanthanide shift reagent (LSR) Yb(fod)~3~ and the data analyzed using the lanthanide induced shift (LIS) ratio method. Studies were carried out on phenalenone, 6βmethoxyphenalenone,
## Abstract The use of lanthanideβinduced shifts for rigorous structure analysis requires accurate values corresponding to only one of the complexes that can be formed. A combination of computational and experimental studies have been carried out to evaluate several commonly used procedures for obt