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Interactions between protonated retinal schiff base and various counter ions: A study by two-dimensional NOE NMR spectroscopy

✍ Scribed by Rodolfo Ghirlando; Elisha Berman; Timor Baasov; Mordechai Sheves


Publisher
John Wiley and Sons
Year
1987
Tongue
English
Weight
397 KB
Volume
25
Category
Article
ISSN
0749-1581

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✦ Synopsis


Using two-dimensional NMR spectroscopy, the spatial location of various carboxylate anions relative to the polyene chain of the protonated Schiff base of all-trans-retinal was determined. The observed intermolecular NOE cross-peaks between a proton on the counter ion and a proton near the nitrogen atom indicate the existence of ion-pair formation between the protonated retinal Schiff base and various counter ions in chloroform. The results suggest that the most likely site of the carboxylate group of the counter ion is in the immediate vicinity of the positively charged nitrogen atom of the retinal Schiff base.