Hydrogen bonds determine the signal arrangement in 13C NMR spectra of nicotinate

Present work reports on studies of sodium nicotinate solutions in water and aqueous ethanol by means of H-1, C-13, N-15 NMR spectroscopy. The H(2) nucleus was observed to be the least shielded among pyridine ring protons whilst C(6) signal placed in the lowest field in relation to the other pyridine carbons. The hydrogen bonds formation between nicotinate and water molecules was shown to be probable reason of signal arrangement in C-13 NMR spectra of nicotinate. The heteronitrogen of nicotinate is less prone to the hydrogen bonding with water molecules than that of nicotinamide. The data on the change in the Gibbs energy of the nicotinate transfer and the results of the 13C NMR experiment are compared. (C) 2017 Elsevier B.V. All rights reserved.