A High-Precision Carbon-13 Shift Thermometer for the Temperature Range 100–300 K

The Barrier to Rotation around N−O Bonds in 4-Substituted N-Isopropoxythiazole-2(3H)-thiones and in N-Isopropoxy-2(1H)-pyridinethione

“…(1) (2) Reliable temperatures (Ϯ1 K) were measured using a solution of a semibullvalene-derived high-precision carbon-13 shift thermometer in CHF 2 Cl/(CD 3 [15] These data were applied in order to calculate the activation parameters lg A, E a , ∆H ‡ , and ∆S ‡ for the topomerization process in pyridinethione 1 (125Ϫ185 K) and the thiazolethiones 2 and 3 [195Ϫ260 K, Figure 3, Equation (3), Table 1]. A full report on the experimental data (temperatures, linewidths, and rate constants) is provided in the Supporting Information.…”

“…The residue was purified by column chromatography [SiO 2 , petroleum ether/diethyl ether, 1:1 (v/v), R f ϭ 0.35] to afford isopropoxythiazolethione 2 as a tan oil (118 mg, 85%). 1 [15] were prepared in high precision 5 mm tubes (Varian 507 PP) which were attached to a vacuum line (10 Ϫ2 Torr) connected to the sources of CHClF 2 and [D 6 ]dimethyl ether. The tubes were evacuated at 77 K/ 10 Ϫ2 Torr and the solvents were added carefully at this temperature in a ratio of 3:1.…”

“…Carbon-13 spectra were recorded with WALTZ-16 decoupling. [15] Zero filling to four times the number of measured data points was performed. Particular attention was paid to the phase and the baseline corrections.…”

New Zwitterionic Spirocyclic λ5Si-Silicates with Two Ethane-1,2-diolato(2-), Oxalato(2-), or Benzene-1,2-diolato(2-) Ligands - Synthesis, Structure, and Dynamic Behavior

“…The thermocouple used with the probe was calibrated for low temperatures according to ref. [24] using a saturated solution of a certain semibullvalene derivative in ClF 2 CH/CD 3 OCD 3 . Spectra were recorded in the temperature ranges of 152±296 K (7, CD 2 Cl 2 ), 233±296 K (8, CD 3 CN), and 198±296 K (9, [D 6 ]acetone).…”

Real-time imaging of the spatial distribution of rf-heating in NMR samples during broadband decoupling

“…Several compounds with temperature-dependent chemical shifts have been reported as NMR-thermometers, involving 1 H, 2 H, 19 F, 13 C, 31 P [7] and 129 Xe [8]. One of the most temperature-sensitive NMR resonances is observed for 59 Co [9], which can easily be measured in highly symmetric complexes like hexacyanocobaltate(III), CoðCNÞ 6 3À .…”