Chlorobis(dppe)iron hydride

Chlorobis(dppe)iron hydride is a coordination complex with the formula HFeCl(dppe)2, where dppe is the bidentate ligand 1,2-bis(diphenylphosphino)ethane. It is a red-violet solid. The compound has attracted much attention as a precursor to dihydrogen complexes.[1]

Chlorobis(dppe)iron hydride
Names
IUPAC name
Chlorohydridobis(bis-1,2-(diphenylphosphino)ethane)iron(II)
Identifiers
3D model (JSmol)
Properties
C52H49ClFeP4
Molar mass 889.09
Appearance red-violet solid
Melting point 195 °C (383 °F; 468 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Structure

The complex exhibits octahedral molecular geometry. The chloride and hydride ligands are mutually trans.[2] The bond distances between the iron metal atom and the coordinating ligands are given by the following:

BondBond distance
Fe-P12.238
Fe-P22.256
Fe-P32.236
Fe-P42.255
Fe-Cl2.404
Fe-H1.313

Synthesis and reactions

The compound is synthesized according to this idealized reaction:[3]

FeCl2 + 2 dppe + Na[BH4] → NaCl + ½ B2H6 + HFeCl(dppe)2
"Top-view" of the structure of HFeCl(dppe)2

In the course of this conversion, high-spin complex FeCl2(dppe)2 converts to low-spin HFeCl(dppe)2.

The complex HFeCl[(dppe)2 exhibits a number of reactions associated with the remaining Fe-Cl bond. Reaction of the complex with sodium borohydride gives the dihydride complex:

HFeCl(dppe)2 + NaBH4 → H2Fe(dppe)2 + NaCl + "BH3"

Removal of chloride using sodium tetrafluorborate under and atmostphere of hydrogen or nitrogen gives the dinitrogen and dihydrogen complexes:[4]

HFeCl(dppe)2 + NaBF4 + N2 → [HFe(N2)(dppe)2]BF4 + NaCl
HFeCl(dppe)2 + NaBF4 + H2 → [HFe(H2)(dppe)2]BF4 + NaCl

References
  1. Morris, R. H. (2008). "Dihydrogen, Dihydride and in Between: Nmr and Structural Properties of Iron Group Complexes". Coord. Chem. Rev. 2252 (21–22): 2381–2394. doi:10.1016/j.ccr.2008.01.010.
  2. Lee, J.; Jung, G.; Lee, S. W. Structure of trans-chlorohydridobis(diphenylphosphinoethane)iron(II). Bull. Korean. Chem. 1998, 19, 267. ISSN 0253-2964
  3. Giannoccaro, P.; Sacco, A. (1977). "Bis[ethylenebis(diphenylphosphine)]-Hydridoiron Complexes". Inorganic Syntheses. Inorg. Synth. Inorganic Syntheses. 17. p. 69–71. doi:10.1002/9780470132487.ch19. ISBN 9780470132487.CS1 maint: uses authors parameter (link)
  4. Bautista, M. T., Bynum, L. D., Schauer, C. K. (1996). "Synthesis of η2-Dihydrogen Complex, trans-{Fe(η2-H2)(H)[1,2-bis(diphenylphosphino)ethane]2}[BF4]: An Experiment for an Advanced Inorganic Chemistry Laboratory Involving Synthesis and NMR Properties of an η2-H2 Complex". Journal of Chemical Education. 73: 988–991. doi:10.1021/ed073p988.CS1 maint: uses authors parameter (link)
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