Charge Transfer Properties of Multi(ferrocenyl)trindenes

Ferrocenyl, diferrocenyl, and triferrocenyl complexes of dihydro-1H-trindene have been prepared by up to 3-fold bromide substitution of the dihydro-2,5,8-tribromo-1H-trindene halocarbon. The charge transfer properties of their mono-, di-, and tricationic derivatives were investigated. The cations of this new family of multi(ferrocenyl)trindene complexes were generated by chemical oxidation using (acetylferrocenium)(BF4) as the oxidative agent and monitored in the visible, IR and near-IR regions. The charge transfer bands in the near-IR spectra are rationalized in the framework of the Marcus\u2013Hush theory. In particular, the triferrocenyl complexes display a redox chemistry that can be switched from a unresolved three-electron oxidation to two consecutive one-electron and two near simultaneously occurring one-electron oxidations by changing the supporting electrolyte from [nBu4N][PF6] to [nBu4][B(C6F5)4]. In addition, the introduction of the third ferrocenyl group increases the strength of the metal\u2013metal interaction with respect to that of the structurally related diferrocenyl system

Charge Transfer Properties in Cyclopenta[l]phenanthrene Ferrocenyl Complexes

The new complexes (2-ferrocenyl)cyclopenta[l]-phenanthrene and (2-ferrocenyl)(eta(5)-cyclopenta[l]phenanthrenyl)FeCp have been prepared and the charge transfer properties of their monocationic derivatives investigated. The cations were generated by chemical oxidation using ferrocenium(BF4) or acetylferrocenium(BF4) as the oxidative agent and monitored in the visible, IR, and near-IR regions. The electrochemistry of the two complexes and, for comparison, of the previously reported (eta(5)-cyclopenta[l]phenanthrenyl)FeCp was analyzed. The charge transfer bands in the near-IR spectral region of the monocations are rationalized in the framework of Marcus-Hush theory. In particular, the monometallic (2-ferrocenyl)cyclopenta[l]phenanthrene displays a single oxidation wave at a potential very close to that of (eta(5)-cyclopenta[l]phenanthrenyl)FeCp and its monocations exhibits a ligand-to-metal charge transfer band in the visnear-IR region. The unsymmetrical diiron species (2-ferrocenyl)(eta(5)-cyclopenta[l]phenanthrenyl)FeCp undergoes two consecutive and well-resolved one-electron oxidations producing, at the first oxidation step, a mixed-valence monocation which displays an intervalence charge transfer band in the vis-near-IR region

Coordination ability of free or silica immobilized Schiff bases towards Hg(II), Cd(II) and Pb(II) ions

A series of ligands, consisting of Schiff bases and their reduced amine derivatives, was prepared by [2+1] condensation of 3-methoxy (or 3-ethoxy)-2-hydroxybenzaldehyde or 2-hydroxybenzaldehyde with 3,4-diaminobenzoic acid or 1,2-diaminobenzene, and by subsequent reduction with hydrogen or NaBH4. The complexation behavior of these ligands towards Cd(II), Pb(II) and Hg(II) salts was tested and the resulting complexes characterized by elemental analysis, IR and NMR spectroscopy, ESI-MS mass spectrometry and SEM-ESEM microscopy. Ligand-bearing silicas were prepared by the reaction of a carboxylic group at the periphery of the coordinating moiety of the Schiff bases or amine derivatives with functionalized silicas bearing NH2 or Cl groups. Ligand-bearing silicas were characterized by elemental analysis, IR spectroscopy and SEM-ESEM microscopy. Finally, the capability of these materials to sequestrate the above mentioned metal ions from water solutions was studied. Preliminary data on the selective recognition of mercury ions from cadmium and lead ions are reporte

Synthesis, Structural characterization and Exafs investigations of new ruthenium(III) complexes.

Two new complexs of Ru(III) with glucosaminic acid and 1-Methyluracil, [RuCl2(Glun-N,O)2]H (I), (Glun-= glucosaminate); [RuCl4(1-MeU-N3)(DMSO)]H2.H2O (II), (1-MeU-= 1-Methyluracilate) were prepared from the same Ru(III) precursors, RuCl3•3H2O and [(DMSO)2H][trans-RuCl4(DMSO)2]. The characterization of the complexes have been carried out by elemental analysis, FT-IR, ES-MS, NMR and EXAFS