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.
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:
Synthesis and reactions
The compound is synthesized according to the following idealized reaction:3
FeCl2 + 2 dppe + Na[BH4] → NaCl + ½ B2H6 + HFeCl(dppe)2In 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 + NaClReferences
Morris RH (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. /wiki/Doi_(identifier) ↩
Lee, J.; Jung, G.; Lee, S. W. Structure of trans-chlorohydridobis(diphenylphosphinoethane)iron(II). Bull. Korean. Chem. 1998, 19, 267. ISSN 0253-2964 /wiki/ISSN_(identifier) ↩
Giannoccaro, P.; Sacco, A. (1977). "Bis[Ethylenebis(Diphenylphosphine)]-Hydridoiron Complexes". Inorganic Syntheses. Vol. 17. pp. 69–71. doi:10.1002/9780470132487.ch19. ISBN 9780470132487. {{cite book}}: |journal= ignored (help) 9780470132487 ↩
Bautista MT, Bynum LD, Schauer CK (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 (10): 988–991. doi:10.1021/ed073p988. /wiki/Doi_(identifier) ↩