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Paramagnetically Shifted High-Resolution Proton NMR Spectra of Poly(methyl methacrylate) by the use of Tris(dipiyalomethanato)europium(III).

Tris(dipivalomethanato)europium(III), as the NMR shift reagent has been applied to the NMR measurement of four types of poly(methyl methacrylate) samples in benzene solution. The time dependences of the chemical shifts of the polymers were measured. Chemical shifts become larger and larger till about 100 min after the addition of the shift reagent in polymer solutions and subsequently they did not vary further for several hours. It is found that the isotropic shifts of these polymers are inversely proportional to the absolute temperature between 300 and 373°K, all the polymer signals shift to lower fields linearly with increasing amounts of the shift reagent. Moreover the separation of the methoxy signal attributable to the pentad tacticity was observed.