Bromopentacarbonylrhenium(I)

Bromopentacarbonylrhenium(I) is an inorganic compound of rhenium, commonly used for the syntheses of other rhenium complexes.

Bromopentacarbonylrhenium(I)
Names
IUPAC name
Bromidopentacarbonylrhenium
Identifiers
3D model (JSmol)
ECHA InfoCard 100.034.607
EC Number
  • 238-084-8
  • InChI=1S/5CO.BrH.Re/c5*1-2;;/h;;;;;1H;/q;;;;;;+1/p-1
    Key: NWJBOTGGBYFKEJ-UHFFFAOYSA-M
  • [C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].[C-]#[O+].Br[Re]
Properties
Re(CO)5Br
Molar mass 406.16 g/mol
Appearance colorless
Melting point sublimes 85-90 °C (0.2 mm Hg)
Solubility in chlorocarbons soluble
Hazards
GHS labelling:
GHS06: ToxicGHS07: Exclamation mark
Danger
H301, H311, H315, H319, H331, H335
P261, P264, P270, P271, P280, P301+P310, P302+P352, P304+P340, P305+P351+P338, P311, P312, P321, P322, P330, P332+P313, P337+P313, P361, P362, P363, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Preparation

Bromopentacarbonylrhenium(I) is commercially available. It is also easily and inexpensively synthesized by the oxidation of dirhenium decacarbonyl with bromine:[1]

Re2(CO)10 + Br2 → 2 ReBr(CO)5

It was first prepared by the "reductive carbonylation" of rhenium(III) bromide:[2]

ReBr3 + 2 Cu + 5 CO → BrRe(CO)5 + 2 CuBr

Copper(I) bromide is a byproduct.

Reactions

Bromopentacarbonylrhenium(I) is a precursor to other rhenium complexes. It reacts with zinc and acetic acid to give pentacarbonylhydridorhenium (HRe(CO)5).[3]

Re(CO)5Br + Zn + HO2CCH3 → ReH(CO)5 + ZnBrO2CCH3

It also reacts with tetraethylammonium bromide in diglyme to give [NEt4]2[ReBr3(CO)3)], an important precursor to compounds containing the rhenium tricarbonyl fragment.[4]

Heating bromopentacarbonylrhenium(I) in water give the triaquo complex:

ReBr(CO)5 + 3 H2O → [Re(H2O)3(CO)3]Br + 2 CO

This route avoids the formation of the tetraethylammonium bromide byproduct, which is often difficult to remove from reaction mixtures.[5]

References
  1. Steven P. Schmidt; William C. Trogler; Fred Basolo (1990). Pentacarbonylrhenium Halides. Inorganic Syntheses. Vol. 28. pp. 154–159. doi:10.1002/9780470132593.ch42. ISBN 9780470132593.
  2. W. Hieber; Hans Schulten (1939). "XXX. Mitteilung über Metallcarbonyle. Über Rhenium-Kohlenoxyd-Verbindungen". Zeitschrift für anorganische und allgemeine Chemie. 243 (2): 164–173. doi:10.1002/zaac.19392430205.
  3. Michael A. Urbancic; John R. Shapley (1990). Pentacarbonylhydridorhenium. Inorganic Syntheses. Vol. 28. pp. 165–8. doi:10.1002/9780470132593.ch43. ISBN 9780470132593.
  4. R. Alberto; A Egli; U. Abram; K. Hegetschweiler; V. Gramlich & P. A. Schubiger (1994). "Synthesis and Reactivity of [NEt4]2[ReBr3(CO)3]. Formation and Structural Characterization of the Clusters [NEt4][Re3(μ3-OH)(μ-OH)3(CO)9] and [NEt4][Re2(μ-OH)3(CO)6] by alkaline titration". J. Chem. Soc., Dalton Trans. (19): 2815–2820. doi:10.1039/DT9940002815.
  5. N. Lazarova; S. James; J. Babich & J. Zubieta (2004). "A convenient synthesis, chemical characterization and reactivity of [Re(CO)3(H2O)3]Br: the crystal and molecular structure of [Re(CO)3(CH3CN)2Br]". Inorganic Chemistry Communications. 7 (9): 1023–1026. doi:10.1016/j.inoche.2004.07.006.
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