Martin Antberg

Oligophosphan-Liganden: XXV. cis-FeH2[P(CH2CH2CH2PMe2)3]: Synthese und Reaktionen☆

Treatment of FeCl2(pp3) (pp3 = P(CH2CH2CH2PMe2)3) with LiAlH4 in THF gave FeH2(pp3) (I). Compound I reacted with methyl iodide to form mixtures of FeHI(pp3) (II) and FeI2(pp3) (III). HBF4 interacted with I to give the ionic complex [FeH(pp3)]BF4 (IV) the cation of which was observed to be stereochemically non-rigid on the 31P NMR time scale. The conversion of I into the trihydrido derivative [FeH3(pp3)]BF4 failed. Reactions of IV with MeCN, N2 and CO led to [FeH(MeCN)(pp3)]BF4 (V), [FeH(N2)(pp3)]BF4 (VI) and [FeH(CO)(pp3)]BF4 (VII), respectively. Exposure of I to an atmosphere of CO2 produced carbon monoxide and Fe(O2CO)(pp3) (VIII). The synthesis of the cyclometallated complex [Me2P(CH2)3]2P(CH2)3P(Me)CH2−FeH (IX) by photolysis of I is also described.

Oligophosphan-Liganden, XXIII. Synthese und Chemie des metallacyclischen Eisenkomplexes / Oligophosphine Ligands, XXIII. Synthesis and Chemistry of the Metallacyclic Iron Complex

The complex (1) was obtained by reduction of FeCl2[P(CH2CH2CH2PMe2)3] with lithium dust in tetrahydrofuran at room temperature. Although an equilibrium of 1 with its iron(0) tautomer Fe[P(CH2CH2CH2PMe2)3] could not be detected by NMR spectroscopy, the coordinatively unsaturated 16e-fragment could be trapped by ligands favouring low oxidation states: trimethyl phosphite reacted with 1 to give Fe[P(OMe)3][P(CH2CH2CH2PMe2)3] (2), whereas carbon monoxide was observed to add to the metal(O) species to yield a mixture of Fe(CO)[P(CH2CH2CH2PMe2)3] (3) and -(CH2)3-PMe2 (4). 1 was completely unreactive towards dihydrogen and dinitrogen, not, however, towards carbon dioxide, which was found to insert into both the Fe-H and Fe-C bond producing (5). Methyl and benzyl iodide interacted with 1 to give the iodo derivative (6). The reaction of 1 with methanol lead to FeH2[P(CH2CH2CH2PMe2)3] (7).

Oligophosphan-Liganden, X II [1] Pseudohalogeno- und Halogenohydridoeisen(II)-Komplexe des tripodal-tetratertiären Phosphanliganden P(CH2CH2CH2PMe2)3 / Oligophosphine Ligands, X II [1] Pseudohalo and Halohydro Complexes of Iron (II) Containing the Tripod Tetratertiary Phosphine Ligand P(CH2CH2CH2PMe2)3

The iron(II) complexes FeX2[P(CH2CH2CH2PMe2)3] with X = CN (4), N3 (5). and NCS (6) have been prepared by metathetical reaction of FeCl2[P(CH2CH2CH2PMe2)3] (1) with the corresponding sodium pseudohalide. Treatment of the dihalo compounds FeX2[P(CH2CH2CH2PMe2)3] (X2 = Cl2 (1). Br2 (2), I2 (3)) with LiAlH4 gave the halohydro derivatives FeHX[P(CH2CH2CH2PMe2)3], where HX = HCl (7). HBr (8). and HI (9). Consistent with a cis-octahedral coordination geometry, the 31P NMR spectra of 1−9 exhibit AMX2 type splitting. The halohydro complexes 7−9 have also been studied by IR and 1H NMR spectroscopy. 57Fe Möβbauer data have been collected for compounds 1, 4, and 5.