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Study on the synthesis of the lanthanide chelates of α′‐(trifluoromethyl)polyfluoroalkyl β‐diketones and their application as 1 H NMR shift reagents
Author(s) -
WeiYuan Huang,
LongQing Zhang
Publication year - 1987
Publication title -
acta chimica sinica english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 0256-7660
DOI - 10.1002/cjoc.19870050408
Subject(s) - chemistry , lanthanide , trifluoromethyl , reagent , ether , proton nmr , ketone , alcohol , chelation , medicinal chemistry , chemical shift , substrate (aquarium) , stereochemistry , inorganic chemistry , organic chemistry , ion , alkyl , oceanography , geology
The synthesis of the lanthanide chelates of α′‐(trifluoromethyl)polyfluoroalkyl β‐diketones Ln {CF 3 CF 2 [CF 2 OCF(CF 3 )] n COCHCOC(CH 3 ) 3 } 3 [ 1 , n =1; Ln=Eu (1a) , Pr (1b) , Nd (1c) , Sm (1d) , Gd (1e) , Tb (1f) , Dy (1g) , Er (1h). 2 , n =2; Ln=Eu (2a) , Pr (2b) , Nd (2c) , Sm (2d) , Gd (2e) , Tb (2f) , Dy (2g) and Er (2h) ] was reported and the 1 H NMR shift properties were studied using alcohol, ketone, ether and amine as substrates. Compounds 1a, 1b, 2a and 2b induce shifts similar to that induced by Ln(fod) 3 (Ln=Eu, Pr). However compounds 1a and 2a are superior to Eu(fod) 3 , because their 1 H signal shifts to higher field in the presence of substrate than that of Eu(fod) 3 , does. For example, Δh for 1a and 2a is close to zero ppm in the presence of alcohol. A very satisfactory first order spectra can be obtained using 1a, 2a, 1b and 2b as 1 H NMR shift reagents. 1c, 1f, 1g, 2c, 2f and 2g produce upfield shifts, and 1h and 2h produce downfield shifts. 1c and 2c induce shifts smaller than that of 1b and 2b , whereas 1f, 1g, 1h, 2f, 2g and 2h induce very large shifts.