observing the 1H nuclei at 400.13 MHz. For this, aliquots of approximately 10 ml of each sample were directly transferred into 5-mm NMR tubes and the volume was completed to 500 ml with CDCl3 containing 5 103 g L1 TMS. The 1H NMR spectra were recorded at 30 C. by accumulating thirty two scans, a relaxation delay of 1 s, spectral width of ~ ¼ 9.1 ppm and 64 K data points. The 1H NMR chemical shifts are expressed in ppm related to the TMS signal at 0.00 ppm as internal reference.NMR ที่ วิเคราะห์ได้จะถูกBruker 400 spectrometer NMR การดำเนินการที่ 9.4 T