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Brendan Twamley PhilipP. Power 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2000,112(19):3643-3646
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Isomerization at the Complexation of 3-Acetyltetramic Acid: Structure and Magnetic Properties of the CuII- and NiII-Complex of 2,7-Bis (1′, 5′, 5′ -trimethylpyrrolidin-2′,4′ -dion-3′ -yl)-3,6-diazaocta-2,6-dien 2,7-Bis(1′, 5′, 5′ -trimethylpyrrolidin-2′, 4′ -dion-3′ -yl)-3,6-diazaoctadien formes CuII and NiII complexes with different constitutions (because of the Z/E isomerization). Results of X-ray analysis of N,N′ -ethylenbis(1′, 5′, 5′ -trimethylpyrrolidin-2′, 4′ -dion-3′ -acetiminato)nickel(II) 1 respectively -copper(II) 2 shows, that the complexing agent in 1 occurs in the E-form, whereas the ligand of the CuII complex forms the Z-form. Magnetic susceptibility and shift effects of the 13C-NMR signals point to a weak paramagnetism of the NiII complex. ESR-spectra are obtained from 2 only. Furthermore, the CuII complex reduces the relaxation times T1 and T2 of 1H and 17O nuclei spins from water. From the temperature dependence of the shortening of the relaxation times an activation energy is calculated which describes the reorientation of the copper complex in the “water matrix”. 相似文献
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The model of Davis and Willcott can be successfully applied to 1H NMR lanthanide induced shifts (LIS) of 2-methyltetrahydropyran in the presence of Eu(dpm)3. By contrast, the model does not work in the case of cis-4-methyl-2-(2′-methyl-1′-propenyl)tetrahydropyran (cis-Rosenoxide), probably due to the presence of more than one LSR-substrate complex in the solution. 相似文献