Synthesis, Structural Characterization, and Catalytic H2 Production of Ferrocenyl (Fc) Group Containing Complexes [Ni(PFc2NAr2)2](BF4)2 (Ar = Ph, p-BrC6H4)

Abstract

Two new ferrocenyl (Fc) group containing 1,5-diaza-3,7-diphosphacyclooctane ligands, PFc2NAr2 (1, Ar = Ph; 2, Ar = p-BrC6H4), were prepared by reaction of FcPH2 with 2 equiv of paraformaldehyde in glycol followed by treatment of the resulting FcP(CH2OH)2 with 1 equiv of aniline or p-bromoaniline in 79% and 67% yields, respectively; however, ligands 1 and 2 could be also prepared by treatment of the isolated and purified FcP(CH2OH)2 with 1 equiv of aniline or p-bromoaniline under similar conditions in 80% and 72% yields, respectively. Further treatment of 1 or 2 with the complex salt [Ni(MeCN)6](BF4)2 in MeCN at room temperature resulted in formation of the first ferrocenyl-containing complexes [Ni(PFc2NAr2)2](BF4)2 (3, Ar = Ph; 4, Ar = p-BrC6H4) in 95% and 90% yields, respectively. Compounds 1–4 were structurally characterized by elemental analysis and spectroscopy and particularly for 1, 2, and 4 by X-ray crystallography. When the cyclic voltammetric behavior of 1–4 was investigated, 3 and 4 were found t...