Association of symmetrical alkane diols with pyridine: DFT/GIAO calculation of H-1 NMR chemical shifts

作者：Lomas John S; Joubert Laurent; Maurel Francois

来源：Magnetic Resonance in Chemistry, 2016, 54(10): 805-814.

DOI：10.1002/mrc.4457

• diols
• pyridine
• Gaussian 09
• GIAO
• cooperativity
• QTAIM-IQA
• NCI

Proton nuclearmagnetic resonance (NMR) shifts of the free diol and of its 1 : 1 and 1 : 2 hydrogen-bonded complexes with pyridine have been computed for five symmetrical alkane diols on the basis of density functional theory, by applying the gauge-including atomic orbital method to geometry-optimized conformers. For certain conformers, intramolecular OH center dot center dot center dot OH interactions, evidenced by high NMR OH proton shifts, are further enhanced on going from the free diol to the corresponding 1 : 1 diol/pyridine complex. This is confirmed by atoms-in-molecules and non-covalent interaction plots. The computed OH and CH proton shifts for the diol and the two complexes correlate well with values obtained by analysing data from the NMR titration of the diols in benzene against pyridine. Shift values for the diols in neat pyridine are calculated by weighting the shifts of the various protons in the three forms (free diol, 1 : 1 and 1 : 2 diol/pyridine complexes) according to the experimentally determined association constants. The results are in good agreement with those observed, and after empirical scaling, the root mean square difference is 0.18ppm.

• 出版日期2016-10