Bonding, Metal‐Atom Dynamics and Hyperfine Interactions of η‐Phospholyl‐ and η‐Pentaphospholyliron Complexes

Abstract

A number of structurally related sandwich compounds of iron, in which the central metal atom is ligated to rings containing one or five phosphorus atoms, have been investigated by temperature-dependent 57 Fe Mössbauer spectroscopy, differential scanning calorimetry and single-crystal X-ray diffraction. The quadrupole hyperfine interaction at 90 K evidences a linear dependence on the number of ring phosphorus atoms, decreasing by about 0.35 mm·s −1 for each ring carbon atom replaced by P. This effect is directly related to the

Metal Atom Vibrational Amplitudes in Decamethylferrocene and Related Organometallics

“…The difference between the calculated M eff (85 D) and the "bare" atom mass (57 D) reflects the covalency of the metal atom-ligand interaction, as discussed earlier. [19] The [k 2 Ͻx 2 Ͼ] 1/2 values at five different temperatures, calculated from the ln A(T) data as noted above, and making the assumption that the high-temperature limiting slopes extrapolate to f = 0 as T Ǟ 0, are summarized graphically in Figure 5. Finally, a related organometallic structure in which the iron atom is ligated to two five-membered rings and in which there are five methyl groups on the C 60 sphere, in near proximity to the metal center, is provided by the "bucky ferrocene" compound 4, for which the details of the ME parameters have been reported earlier.…”

Metal Atom Dynamics and Spin-Lattice Relaxation in Multilayer Sandwich Compounds

“…Both the fast spin-lattice relaxation noted for I and related phospholyl complexes [7], as well as the magnitude of the QS interactions in these complexes, as well as in II and III, compared to values reported earlier for ferrocenoid complexes without ring phospholyl groups, is presumably associated with the difference in the metal atomYligand bonding obtaining in these compounds. An MO correlation diagram for 5 YN 5 ligands has been discussed by Frenking [8], and for 5 YP 5 by Schleyer et al [9] and Malar [10].…”

“…More recently, a detailed study of a number of ferrocene-related compounds, in which one or more of the ligand rings contain one or several P atoms, and which have been subjected to a one-electron oxidation process, have been described in the literature [7], including several multi-layer sandwich compounds in which the iron-containing cationic moieties are accompanied by a balancing anion such as BF 4 j and PF 6 j . A compound of particular interest in this regard is the paramagnetic complex 5 YCp*FeY 5 YP 5 Fe 5 YCp* + BF 4 j (I) [where Cp* is pentamethyl cyclopentadienyl] which is related both to 5 YCp*FeY 5 YP 5 (II) (neutral) and 5 YCp* Fe 5 YP 5 Fe 5 YCp + PF 6 j (III) (paramagnetic).…”

The Interaction of 1,1′‐Diphosphaferrocenes with Gold: Molecular Coordination Chemistry and Adsorption on Solid Substrates

“…Pertinent bond lengths and angles are collected in Table , which also includes reported data for the structurally characterised known compounds of our study, viz. 3,3′,4,4′‐tetramethyl‐1,1′‐diphosphaferrocene ( 2 ), octamethyl‐1,1′‐diphosphaferrocene ( 4 ), and octaethyl‐1,1′‐diphosphaferrocene . Additionally, 2,2′,5,5′‐tetraphenyl‐1,1′‐diphosphaferrocene ( 7 ) has been included for comparison, since this known compound is an isomer of the new derivative 3,3′,4,4′‐tetraphenyl‐1,1′‐diphosphaferrocene ( 3 ) …”