Details

Autor(en) / Beteiligte

• Henry, Renee M
• Shoemaker, Richard K
• Newell, Rachel H
• Jacobsen, George M
• DuBois, Daniel L
• Rakowski DuBois, M

Titel

Stereochemical Control of Iron(II) Complexes Containing a Diphosphine Ligand with a Pendant Nitrogen Base

Ist Teil von

• Organometallics, 2005-05, Vol.24 (10), p.2481-2491

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2005

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A series of cis and trans Fe(II) complexes containing the diphosphine ligand PNP (where PNP is bis((diethylphosphino)methyl)methylamine) have been prepared and isolated. These include cis-[Fe(PNP)2(CH3CN)2](BF4)2 (3), cis-[Fe(PNP)2(CH3CN)(CO)](BF4)2 (4), trans-[Fe(PNP)(dmpm)(CH3CN)2](BF4)2 (5), trans-Fe(PNP)(dmpm)Cl2 (6), trans-[Fe(PNP)(dmpm)(CO)Cl]2[FeCl4] (7), trans-HFe(PNP)(dmpm)Cl (8), and trans-[HFe(PNP)(dmpm)(CH3CN)]BPh4 (9) (where dmpm is bis(dimethylphosphino)methane). In addition, the cations trans-[HFe(PNP)(dmpm)(CO)]+ (10) and trans-[(H2)Fe(PNP)(dmpm)(H)]+ (11) have been observed in solution. These complexes all possess a pendant base that bridges the two phosphorus atoms of the PNP ligand. A cis geometry is observed for those complexes containing two PNP ligands, whereas a trans geometry is observed for the complexes containing one PNP ligand and one dmpm ligand. The molecular structures of cis-[Fe(PNP)2(CH3CN)(CO)](BPh4)2 and trans-[HFe(PNP)(dmpm)(CH3CN)]BPh4 have been confirmed by X-ray diffraction studies. Protonation of 5, 7, and 10 occurs at the nitrogen atom of the PNP ligand, and pK a values are reported for the corresponding protonated complexes. The formation of the dihydrogen complex [trans-[(H2)Fe(PNP)(dmpm)(H)]+ and the protonated PNHP complex trans-[HFe(PNHP)(dmpm)(CO)]2+ demonstrate that intramolecular heterolytic cleavage of the dihydrogen ligand can be controlled by varying the nature of the ligand trans to the incipient dihydrogen ligand.