. 2014 May 12;79(11):5315–5319. doi: 10.1021/jo500452b

Table 1. Effect of pH and Counterions on ¹⁹F NMR of β,γ-CHF-UTP 1.

			¹⁹F NMR
base	counterion^a	pH	Δδ (Hz)^b	SF (MHz)^c	Δδ (ppm)^b
dG^d	Na⁺	10.5	22.6	376	0.060
U	Na⁺	10.4	24.0	470	0.051
U	Na⁺	10.4	29.6	564	0.052
U	K⁺	12.7	23.5	470	0.050
U	K⁺	12.7	28.4	564	0.050
U	NH₄⁺	10.1	22.5	470	0.048
U	NH₄⁺	10.1	26.8	564	0.047
U^e	NH₄⁺	nd^f	nd	235	nd

The ionic radii of for Na⁺, K⁺, and NH₄⁺ are 1.02, 1.38, and 1.50 Å, respectively.²⁴ Ionic radii are not readily available for bulky alkylammonium cations, but instead rely on partial molar volume.²⁵ As a representative example, the ionic radius of tetramethylammonium is 3.47 Å.²⁴

Δδ is the δ difference between the overlapping diastereomers given in Hz and ppm, respectively.

SF is the spectrometer frequency given in MHz.

Lit. value.¹⁷

Lit. value, cation inferred.²²

The pH was not reported for the spectrum given but is likely below 10.²² A simulation for SF = 235 MHz (Figure S20) assuming a line width at half height of 8 Hz and δ 12 Hz at pH 10 generated a 12-peak multiplet with substantially resolved outer peaks.

Table 1. Effect of pH and Counterions on 19F NMR of β,γ-CHF-UTP 1.

Table 1. Effect of pH and Counterions on ¹⁹F NMR of β,γ-CHF-UTP 1.