Solvent effect on 14N NMR chemical shifts of oxine (8-hydroxyquinoline) and 2methyloxine (8-hydroxyquina1dine) has been studied. The resuhs have been discussed in term of hydrogen-bonding and solvent polarity effects using DMSO-d,s as an internal locking agent and NH.NO] as an external standard. Concentrated solutions have been used to get better signal to noise ratio.1~ chemical shift ofoxine and 2-methyloxine in CCL. are very low i.e. -245.24 ± 14.09 ppm and -148.48 ± 31.18 ppm for oxine and 2-methyloxine respectively. Both compounds show very high shifts in chloroform i.e. -73.95 ± 3.24 ppm and -80.06 ± 14.50 ppm respectively. In acetone and DMSO both oxines, show similar behavior. Oxine shows extremely low 14N chemical shifts in Dioxane i.e. -288.85 ± 1.09 ppm.The present study on 14N chemical. shifts has been done at a frequency of 6.43 MHz using JEOL FX- 90Q IT NMR. A delay time of 400 I!s has been used to avoid the base line rolling due to low frequency and acoustic ringing. NH.NO] has been taken as an external standard and 14N chemical shifts have been measured with respect to NO]" ion of NH.NO].
A W K KHANZADA ,S A PATHAN ,
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