Oxotrichlorobis(triphenylphosphine)rhenium(V)

Oxotrichlorobis(triphenylphosphine)rhenium(V)
IUPAC name Trichloridooxido bis(triphenylphosphane)rhenium(V)
Identifiers
CAS number	17442-18-1
Properties
Molecular formula	ReOCl3(PPh3)2
Molar mass	833.15 g/mol
Appearance	yellow microcrystals
Melting point	205 °C (478 K)
Solubility in water	not soluble in water
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Oxotrichlorobis(triphenylphosphine)rhenium(V) is the chemical compound with the formula ReOCl₃(PPh₃)₂. This yellow, air-stable solid is a precursor to a variety of other rhenium complexes.^[1] In this diamagnetic compound, Re has an octahedral coordination environment with one oxo, three chloro and two mutually trans triphenylphosphine ligands. The oxidation state of rhenium is +5 and its configuration is d².

Synthesis

ReOCl₃(PPh₃)₂ is commercially available, but it is readily synthesized by reaction of perrhenic acid with triphenylphosphine in a mixture of hydrochloric acid and acetic acid. In this reaction, Re(VII) is reduced to Re(V), and triphenylphosphine is oxidized to its oxide.

HReO₄ + 3 HCl + 3 PPh₃ → ReOCl₃(PPh₃)₂ + Ph₃PO + 2 H₂O

The required perrhenic acid solution can be prepared in situ from rhenium(VII) oxide.

Uses

ReOCl₃(PPh₃)₂ is a precursor to a variety of other oxo-, nitridio, and hydrido complexes. It converts to ReH₇(PPh₃)₂ by a treatment with LiAlH₄. ^[2]

ReOCl₃(PPh₃)₂ catalyzes the selective oxidation of secondary alcohols by DMSO, producing the corresponding ketals.^[3]

References

1. ^ Johnson, N. P.; Lock, C. J. L.; Wilkinson, G. (1967). "Complexes Of Rhenium(V)". Inorg. Synth.. Inorganic Syntheses 9: 145. doi:10.1002/9780470132401.ch39. ISBN 9780470132401. 
2. ^ K. Abdur-Rashid, A. J. Lough, and R. H. Morris (2001). "Intra- and inter-ion-pair protonic-hydridic bonding in polyhydridobis(phosphine)rhenates". Canadian Journal of Chemistry 79 (5–6): 964. doi:10.1139/cjc-79-5-6-964. 
3. ^ Pombeiro, A. J. L.; Fatima, M.; Crabtree, R. H. “Technetium and Rhenium: Inorganic & Coordination Chemistry” Encyclopedia of Inorganic Chemistry. John Wiley & Sons: New York, 2006. DOI: 10.1002/0470862106.ia237