Syntheses, Structures and Reactivity of Terminal Phosphido Complexes of Iron(II) Supported by a β‐Diketiminato Ligand

• Published in: European journal of inorganic chemistry 2018-10, Vol.2018 (38), p.4298-4308
• Main Authors: Kaniewska, Kinga, Dragulescu‐Andrasi, Alina, Ponikiewski, Łukasz, Pikies, Jerzy, Stoian, Sebastian A., Grubba, Rafał
• Format: Article
• Language: English
• Subjects: Catalytic activity; Catalytic converters; Coordination compounds; Crystal structure; Dehydrocoupling; Homogeneous catalysis; Inorganic chemistry; Iron; Ligands; Mossbauer spectroscopy; NMR; Nuclear magnetic resonance; N‐Ligands; Phosphides; Phosphines; Polarity; P‐Ligands; Thermal stability; X-ray diffraction
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201800850

We report the synthesis of the first series of terminal phosphido iron complexes supported by a β‐diketiminato ligand (Dippnacnac) and their catalytic activity in dehydrocoupling of secondary phosphines. Anionic and neutral mono‐ or diphosphido complexes were obtained from the reaction of [(Dippnacnac)FeCl2Li(dme)2] with the R2PLi (R = iPr, tBu, Cy, Ph) phosphides by tuning the stoichiometric ratio, polarity of the solvent, and the bulkiness of the substituents at the P‐atom. The structures of the synthesized compounds were determined by single‐crystal X‐ray diffraction, which revealed that the iron sites of the anionic complexes are four‐coordinate, whereas those of the neutral complexes are three‐coordinate with almost planar geometry. These phosphido iron complexes were also characterized by 1H NMR and zero‐field Mössbauer spectroscopy. The thermal stability and reactivity of selected complexes were studied. The catalytic properties of the phosphido complexes were confirmed by investigating the conversion of diphenylphosphine to symmetrical 1,1,2,2‐teraphenyldiphosphane. The facile synthesis of a novel family of iron(II) complexes supported by terminal phosphido ligands is presented. The structures of the terminal phosphido complexes described here could be easily tuned by a judicious choice of solvent and by a change in the stoichiometry of the reaction. A preliminary investigation of the catalytic activity of these phosphido complexes showed that they exhibit good catalytic activity in the dehydrocoupling of phosphines.