A tungsten-183 NMR study of cis and trans isomers of [W(CO)4(PPh3)(PR3)](PR3 = phosphine, phosphite)
✍ Scribed by Laurence Carlton; Avril Emdin; Andreas Lemmerer; Manuel A. Fernandes
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 213 KB
- Volume
- 46
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.2300
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✦ Synopsis
2 ) 3 (trans isomer only). The 183 W chemical shift (obtained by indirect detection using 31 P) is found to be related to the PR 3 ligand parameters ν and θ (Tolman electronic factor and cone angle, respectively) for the cis isomers and to ν (but only poorly to θ ) for the trans isomers. The 183 W-31 P spin coupling constant is also related, less clearly for P-C than for P-N and P-O bonded ligands, to ν. Chemical shifts are referenced to an absolute frequency ( 183 W) = 4.15 MHz, which is proposed as a calibration standard for 183 W NMR. The structures of cis-[W(CO) 4 (PPh 3 )(PMe 3 )] and cis-[W(CO) 4 (PPh 3 ){P(4-C 6 H 4 F) 3 }] are reported.