A Simple Double-Chamber NMR Tube for the Monitoring of Chemical Reactions by NMR Spectroscopy

The development of a simple piece of equipment for monitoring chemical reactions by NMR (nuclear magnetic resonance) spectroscopy is reported. The kit provides full control of the reaction temperature at any time and can be operated in the temperature range from −80 to 130 °C. The core component is a double-chamber coaxial tube consisting of a 5 mm screw-cap tube and a 3 mm glass insert, which allows two reactant solutions to be placed separately in one NMR tube. The tube can be operated from outside the magnet by additional hardware, which affords the mixing of two reactants inside the sensitive coils region of the NMR probe. The tube kit can be used without any expensive hardware modifications at the NMR instrument and is compatible with the uptake of air- and moisture-sensitive compounds. The potential of the device is demonstrated by two low-temperature experiments involving highly reactive silicon(II) species.