Phosphorus chemical shift tensors of phosphido ligands in ruthenium carbonyl compounds: P-31 NMR spectroscopy of single-crystal and powder samples,and ab initio calculations

K Eichele, RE Wasylishen, JF Corrigan, NJ Taylor, AJ Carty, KW Feindel, GM Bernard

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)

Abstract

The phosphorus chemical shift (CS) tensors of several ruthenium carbonyl compounds containing a phosphido ligand, mu-PR2, bridging a Ru-Ru bond were characterized by solid-state P-31 NMR spectroscopy. As well, an analogous osmium compound was examined. The structures of most of the clusters investigated have approximate local C v symmetry about the phosphorus atom. Compared to the "isolated" PH2- anion, the phosphorus nucleus of a bridging phosphido ligand exhibits considerable deshielding. The phosphorus CS tensors of most of the compounds have spans ranging from 230 to 350 ppm and skews of approximately zero. Single-crystal NMR was used to investigate the orientation of the phosphorus CS tensors for two of the compounds, Ru-2(CO)(6)(mu(2)-eta(2)-CdropC-Ph)(mu(2)-PPh2) and Ru-3(CO)(9)(mu(2)-H)(mu(2)-PPh2). The intermediate component of the phosphorus CS tensor, delta(22), lies along the local C-2 axis in both Compounds. The least shielded component, delta(11), lies perpendicular to the Ru-P-Ru plane while the most shielded component, delta(33), lies perpendicular to the C-P-C plane. The orientation of the phosphorus CS tensor for a third compound, Ru-2(CO)(6)(mu(2)-PPh2)(2), was investigated by the dipolar-chemical shift NMR technique and was found to be analogous, suggesting it to be the same in all compounds. Ab initio calculations of phosphorus magnetic shielding tensors; have been carried out and reproduce the orientations found experimentally. The orientation of the CS tensor has been rationalized using simple frontier MO theory. Splittings due to (99,101) Ru-P-31 spin-spin coupling have been observed for several of the complexes. A rare example of Os-189-P-31 spin-spin splittings is observed in the P-31 MAS NMR spectrum of the osmium cluster, where (1)J(Os-189, P-31) is 367 Hz. For this complex, the Os-189 nuclear quadrupolar coupling constant is on the order of several hundred megahertz.

Original languageEnglish
Pages (from-to)1541-1552
Number of pages12
JournalJournal of the Amercian Chemical Society
Volume124
Issue number7
DOIs
Publication statusPublished - 20 Feb 2002

Fingerprint

Dive into the research topics of 'Phosphorus chemical shift tensors of phosphido ligands in ruthenium carbonyl compounds: P-31 NMR spectroscopy of single-crystal and powder samples,and ab initio calculations'. Together they form a unique fingerprint.

Cite this