31p NMR spectra

The 31P NMR spectrum in solution [47] is in accordance with a square planar structure (Figure 2.6). 

The 31P NMR spectrum of wer-RhCl3(PMe3)3 is shown in Figure 2.62 again two of the ligands are equivalent, so the spectrum is a doublet for... 

The 31P NMR spectrum of RhH2Cl(PBu2)2 is shown in Figure 2.69 the triplets show coupling with two equivalent hydrogens, split further by coupling with rhodium (/(Rh-P) 110.3 Hz /(P-H) 14.9 Hz). 

The latter do not yield l,3-dichalcogen-2,4-phosphasilacyclobutanes if they are treated with excess elemental sulfur and tellurium. Compound 23a has been characterized by its 31P-NMR spectrum, which shows a singlet signal at 8 = -126.0, and by l25Te satellites with /(P,Te) = 222 Hz. The composition of 23b,c was proved by mass spectrometry and their... 

Figure 42 is a view of 83 perpendicular to the non-crystallgraphic -axis, which contains the unique phosphorus atom (PI) and interconverts the two equivalent phosphorus atoms (P2). The 31P NMR spectrum, consisting of one doublet and one triplet in a 2 1 ratio, confirms that this structure is maintained in solution. 

The crystalline compound (109) exists in a bicyclic form, as determined by X-ray analysis. In benzene solution absorption of an hydroxyl group appears. At the same time all three methine protons in the H NMR spectra are equivalent and in the 31P NMR spectrum there is only one signal. 

Figure 2.25 31P NMR spectrum of rranr-RhCI(CO)(PBu2Et)2 at -60°C. The patterns x, O, A correspond to the three conformers. (Reproduced with permission from Chem. Comm., 1971,1103.)...

Figure 2.97 31P NMR spectrum (ethyl protons decoupled) of IrH5(PEt2Ph)2. (Reprinted from J. Inorg. Nucl. Chem., 1973, 33, 2195. Copyright (1973) with kind permission from Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington 0X5 1GB, UK.)...

Figure 18. 31P-NMR spectrum of polycrystalline phosphorus pentachloride with magic angle spinning. The two lines arise from the differently shielded PClf and PCl6 ions of which the solid is composed.

The catalyst efficiency of these hydroalumination varies from a turnover number (TON) of 20-91. It is possible that the catalyst is deactivated by the presence of oxygen and water. Examination of the 31P NMR spectrum of the catalyst indicates that the phosphine monoxide and dioxide are formed in the presence of nickel prior to the addition of the substrate. Rigorous exclusion of oxygen and water is necessary in all these reactions. The enantioselective nickel-catalyzed hydroalumination route to dihydronaphthalenols may prove to be particularly important. Only one other method has been reported for the enantioselective syntheses of these compounds microbial oxidation of dihydronaphthalene by Pseudomonas putida UV4 generates the dihydronaphthalenol in 60% yield and >95% ee.1... 

NMR-analyses suggest that the hydrogenation runs corresponding to Scheme 10.3. Three of the four possible catalyst-substrate complexes are detectable in the 31P-NMR-spectrum [57 f]. 

Fig. 10.22 31P-NMR spectrum of a solution of 0.02 mM [Rh((S,S)-DIPAMP)(MeOH)2]BF4 and 0.1 mM (Z)-2-benzoyl-amino-3-(3,4-dimethoxyphenyl)-methyl acrylate.

Phosphacarba- f6>-pentaborane [2-/Bu-l,2-PCB3Fl5] 25 was synthesized by gas-phase reaction of phosphaalkyne with tetraborane(lO) (see Figure 11). In the 31P NMR spectrum a signal at —501 ppm was detected for the apical phosphorus atom and confirmed by quantum mechanical calculations.120... 

The acceptor number, AN, of a solvent is a measure of the power of the solvent to accept a pair of electrons [18], Experimental evaluation of AN involves observing the frequency changes induced by a solvent on the 31P NMR spectrum when triethylphosphine oxide, Et3P=0, is dissolved in the solvent. Donation of an electron pair from the oxygen atom of Et3P=0, as shown in Scheme 1.2, reduces the electron density around the phosphorus, causing a deshielding effect which leads to an increase in chemical shift. Hexane (AN = 0) and SbCls (AN = 100) were used as fixed points to define this scale. 

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