Characterizing SPHOS by 1H, 13C and 31P NMR. This phosphine ligand is widely employed together with e.g palladium in a range of different catalytic reactions.

SPHOS (2-Dicyclohexylphosphino-2′,6′-dimethoxybiphenyl) is a widely used air-stable phosphine ligand employed together with e.g palladium in a range of different catalytic reactions. Figure 1 shows the 1H NMR spectrum of a 800 mM SPHOS sample in CDCl3 measured in a single scan taking 15 seconds to acquire.

 

Figure 1: 1H NMR spectrum of a 800 mM SPHOS sample in CDCl3 measured on a Spinsolve 60 MHz system in a single scan.

31P Spectra

The 31P spectrum of a 800 mM SPHOS sample in CDCl3 is shown in Figure 2. One can clearly identify the single expected 31P resonance at around -10 ppm for the phosphorus atom at position 15. The spectrum was acquired in 5 minutes with 64 scan cycles. In addition, also an impurity could be observed at around 46 ppm, most likely due to some sample degradation.

 

Figure 2: 31P NMR spectrum of a 800 mM SPHOS sample in CDCl3 measured on a Spinsolve 60 MHz system in 64 scans with a total measurement time of 5 minutes

13C Spectra

Figure 3 shows the full 13C NMR spectra of a 800 mM SPHOS sample in CDCl3 acquired using NOE and 1H decoupling (top spectrum).  The bottom spectrum shows a zoom of the chemical shift ranges between 110-150 ppm and 20-40 ppm. All expected resonances can be clearly identified even with the multiplicities defined by the different coupling constants between the 13C atoms and the 31P. This underlines the exceptional signal-to-noise ratio and resolution of the Spinsolve spectrometer.

Figure 3: Carbon NMR spectra of a 800 mM SPHOS sample in CDCl3 measured on a Spinsolve 60 MHz system using NOE and 1H decoupling. Full spectrum (top), zoom to 110-150 ppm and 20-40 ppm (bottom).

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