103Rh chemical shifts

The effect of the bite angle has been reviewed.243,244 The 103Rh chemical shifts of a series of hydridorhodiumbis(carbonyl)diphosphine compounds containing chelating bidentate P-ligands have been obtained by inverse HMQC detection sequences.245... 

Fig. 6. Expansion of the inverse detected 13C/103Rh HMQC NMR spectra of [Rh6(CO)15(P 4 p cgjj4j3)] one-dimensional projections showing the region of the bridging carbonyls. The spectra were obtained with defocusing delays of 17.9 ms 1/(2 JRh.c) a) and 7.14 ms (r 1/(5 /Rh,c), b), respectively. The expected correlations at the true 103Rh chemical shifts are clearly visible in the bottom spectrum, but are very weak or entirely absent in the top spectrum which displays correlations due to three-rhodium spin coherences as the dominant signals. Reproduced from Ref. 33 by permission of The Royal Chemical Society.

Calculated versus experimentally observed 103Rh chemical shifts for 13 complexes are displayed in Fig. 4 [3]. The nonrelativistic DFT computations (B3LYP hybrid functional) were obviously able to achieve excellent agreement with experiment. In comparison, a nonhybrid functional also achieved a linear relation... 

Bender et al. [19] used 103Rh-NMR chemical shift differences to demonstrate an electronic difference at rhodium between two diastereoisomers, and suggested that this might influence the crucial hydrogen addition step. 

An excellent example of the use of 31P chemical shifts, in combination with H-NMR and 103Rh-NMR data as well as coupling constants information, can be found in the report by Duckett et al. [21] on the activation of... 

The results summarized in Figure 2 imply that the observed correlation between 8(103Rh) and catalytic activities for complexes 3 may be indirect rather than intrinsic. The activity is attributed to steric effects related to the bite angle which in turn affects the chemical shifts only indirectly via concomitant changes in the Rh-P bond lengths. 

H and 13C ll NMR spectra for (N)-[I I3Ru3 C6I I5[CH(CH3)CH2)OH] (C6Me6)2(0)]+ show a strong intramolecular hydrogen bond between the p3-oxo cap and the hydroxyl function in acetone solution.346 ll, 13C and 15N chemical shifts were used to probe the coordination of substituted pyridines and aminides to Rh2(02CCF3)4.347 The H, 13C, 31P and 103Rh NMR spectra have been reported for phosphine-phosphonite ferrocenediyl dinuclear rhodium complexes.348 31P NMR data were able to discriminate between enantiomers... 

---