Syntheses and structural characterizations of iron(II) complexes containing cyclic diphosphine ligands with positioned pendant nitrogen bases

George M. Jacobsen, Richard K. Shoemaker, Michael J. McNevin, M. Rakowski Dubois, Daniel L. Dubois

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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.

Original languageEnglish
Pages (from-to)5003-5009
Number of pages7
Issue number20
Publication statusPublished - Sep 24 2007


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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