A series of new iron(II) complexes that contain cyclic diphosphine ligands with pendant amine bases, P2RN2 R′, have been synthesized and characterized (where P 2RN2R′ are substituted 1,5-diaza-3,7-diphosphacyclooctanes). These compounds include [Fe(P 2PhN2Ph)(CH3CN) 4](BF4)2 (5), cis-[Fe(P2 PhN2Ph)2(CH3-CN) 2](BF4)2 (6a), cis-[Fe(P2 PhN2Bz)2(CH3CN) 2](BF4)2 (6b), cis-[Fe(P2 CyN2Bz)2(CH3CN) 2](BF4)2 (6c), trans[HFe(P2 PhN2Ph)2(CH3CN)](BF 4) (7), and cis-Fe(P2PhN2 Ph)2(Cl)2 (8). The molecular structures of 5, 6b, and 7 have been confirmed by X-ray diffraction studies. For all complexes the cyclic diphosphine ligands contain one six-membered ring in a chair conformation and one six-membered ring in a boat conformation. For complex 7, the two rings that are in boat conformations result in N-H distances between the pendant amine nitrogens and the hydride ligand of 2.6 to 2.7 Å. Protonation of the pendant bases in complex 7 has been found to form several products. A structural assignment for a dominant protonated isomer has been assigned on the basis of 1H, 31P, and 15N NMR spectroscopic techniques.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry