Organometallic iron (II) hydrazines and hydrazones — syntheses, characterisations and the X-ray crystal structures of [Fe(η5-Cp)(η6-C6H5NHNH2)]+PF6− and [Fe(η5-Cp)(η6-p-MeC6H4NHNCMe2)]+PF6−

The three new organometallic hydrazines [Fe(η5-Cp)(η6-RC6H4NHNH2)]+PF6−, CpC5H5, RH, [1]+PF6−; m-Me, [2]+PF6−; p-MeO, [3]+PF6−, were synthesised and characterised. They were obtained in CH2Cl2 by reaction of the hydrazine monohydrate, NH2NH2·H2O, with the corresponding precursors [Fe(η5-Cp)(η6-RC6H4Cl)]+PF6−. Similarly to free conventional organic hydrazines, the organometallic hydrazines [1]+PF6− and [3]+PF6− react with acetone affording hydrazones formulated as [Fe(η5-Cp)(η6-RC6H4NHNCMe2)]+PF6−, RH, [6]+PF6−; p-MeO, [7]+PF6−. Likewise, the two other organometallic hydrazones containing the substituent groups Ro-Cl, [8]+PF6− and p-Me, [9]+PF6− were also obtained from their parent hydrazine precursors [4]+PF6− and [5]+PF6−, respectively. All the new compounds were characterised by elemental analysis and IR, UV–vis, 1H- and 13C-NMR spectroscopy. The crystalline and molecular structures of [1]+PF6− and [9]+PF6− were determined by single crystal X-ray crystallographic analysis. Both structures show a cyclohexadienyl-like character at the coordinated C6 ring of the phenylhydrazine and the p-methylphenylhydrazone with a folding angle of 6.0(5) and 7.1(6)°, respectively.