ISSN:
0749-1581
Keywords:
103Rh NMR
;
31P NMR
;
Inverse 2D NMR
;
Square planar
;
Cation
;
Diphosphine
;
Paramagnetic shift
;
Chemical shift correlation
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A series of new and known Rh(I) complexes [Rh(R2P(CH2)nPR2)2]Y and [Rh(diene)(R2P(CH2)nPR2)]Y (R = Me, Et, Ph, C6F5, C6H4CF3; Y = Cl, ClO4, PF4, BF4, OSO2CF3; diene = norbornadiene, cyclooctadiene) were prepared and their 103Rh NMR spectra were recorded on a 100-MHz spectrometer by using inverse two-dimensional 31P, 103Rh{1H} NMR. This technique provides quick access to 103Rh NMR data (2-8 h for ca. 0.1 M samples) when dealing with Rh-phosphine complexes. The 103Rh NMR data are discussed. All δ(103Rh) of the cationic Rh(I) complexes appear at the lower frequency end of the Rh(I) range, i.e. between -1350 and + 200 ppm, which is in agreement with the fact that the Rh shift is determined by σp and with a large ΔE in square-planar d8 complexes. The relative change in ΔE between complexes is not large and the changes in paramagnetic shift for these complexes are essentially determined by their relative σ-donor capacities. δ(103Rh) shows an inverse correlation with δ(31P), which was rationalized by invoking the chelate ring size containing the Rh centre and the bidentate phosphine ligands.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260291320
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