No abstract

NMR spectroscopy, used routinely for structure elucidation, has also become a widely applied tool for process and reaction monitoring. However, the most informative of NMR methods—correlation experiments—are often useless in this kind of applications. The traditional sampling of a multidimensional FID is usually time‐consuming, and thus, the reaction‐monitoring toolbox was practically limited to 1D experiments (with rare exceptions, e.g., single‐scan or fast‐sampling experiments). Recently, the technique of time‐resolved non‐uniform sampling (TR‐NUS) has been proposed, which allows to use standard multidimensional pulse sequences preserving the temporal resolution close to that achievable in 1D experiments. However, the method existed only as a prototype and did not allow on‐the‐fly processing during the reaction. In this paper, we introduce TReNDS: free, user‐friendly software kit for acquisition and processing of TR‐NUS data. The program works on Bruker, Agilent, and Magritek spectrometers, allowing to carry out up to four experiments with interleaved TR‐NUS. The performance of the program is demonstrated on the example of enzymatic hydrolysis of sucrose.

Low‐field benchtop nuclear magnetic resonance (BT‐NMR) spectrometers with Halbach magnets are being increasingly used in science and industry as cost‐efficient tools for the monitoring of chemical reactions, including hydrogenation. However, their use of low‐field magnets limits both resolution and sensitivity. In this paper, we show that it is possible to alleviate these two problems through the combination of parahydrogen‐induced polarization (PHIP) and fast correlation spectroscopy with time‐resolved non‐uniform sampling (TR‐NUS). PHIP can enhance NMR signals so that substrates are easily detectable on BT‐NMR spectrometers. The interleaved acquisition of one‐ and two‐dimensional spectra with TR‐NUS provides unique insight into the consecutive moments of hydrogenation reactions, with a spectral resolution unachievable in a standard approach. We illustrate the potential of the technique with two examples: the hydrogenation of ethylphenyl propiolate and the hydrogenation of a mixture of two substrates – ethylphenyl propiolate and ethyl 2‐butynoate.

No abstract

Benchtop NMR spectrometers have become widely available over the last decade. They are now used successfully in various branches of chemistry. Their popularity continues to grow due to their low...