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The synthesis of the first examples of diastereomerically pure platinacycles having simultaneously a chiral carbon and a sigma[Pt-C(sp(2), ferrocene)] bond is described.

Formation of a carbon–palladium bond to the unsubstituted cyclopentadiene ring occurs during the cyclopalladation of 4‐ferrocenyl‐1,3‐oxazolines and leads to a new type of metalated ferrocene (see scheme). These chiral complexes catalyze the asymmetric aza‐Claisen rearrangement of allylic imidates.

The syntheses, characterization and X-ray crystal structures of the first two examples of asymmetrically bridged dinuclear copper(ii) complexes containing a ferrocenecarboxylato ligand and a methoxo group in [{Cu(dmen)}2(micro-OMe){micro-O2C(eta5-C5H4)Fe(eta5-C5H5)}](ClO4)2, 1, (dmen=N,N-dimethylethylenediamine) or an hydroxo group in [{Cu(tmen)}2(micro-OH){micro-O2C(eta5-C5H4)Fe(eta5-C5H5)}](ClO4)2, 2 , (tmen=N,N,N'N'-tetramethylethylenediamine) are reported. Magneto-chemical studies revealed that 1 and 2 exhibit opposite superexchange interactions between the two Cu(II) paramagnetic centers: an antiferromagnetic coupling (J = -11 cm(-1)) in 1 and a ferromagnetic interaction (J = +29 cm(-1)) in 2. The results obtained from these studies suggest that the weak interactions between the Cu(II) ions and the perchlorate anions detected in the crystal structures are important to introduce significant distortions in the heterobridged [Cu2(micro-OR){micro-O2C(eta5-C5H4)Fe(eta5-C5H5)}]2+ cores of 1 and 2, which clearly affect the nature and strength of the superexchange interactions. Computational studies based on density functional theory and ab initio multiconfigurational second-order perturbation theory (CASPT2) calculations have also been performed in order to rationalize the magnetic behaviour of 1 and 2. The magneto-structural correlations for complexes containing the [Cu(micro-OR)(micro-O2CR')Cu] core are discussed, and the relevance of the out-of-plane angle of the R group with the Cu(micro-OR)Cu plane established.

The synthesis of the novel ferrocenyl Schiff base [(η 5 -C 5 H 5 )Fe{(η 5 -C 5 H 4 )CHdN(C 6 H 4 -2-SMe)}] (1c) and the study of its reactivity versus palladium(II) or platinum(II) salts are reported. These studies have allowed us to isolate and characterize [M{[(η 5 -C 5 H 3 )CHdN(C 6 H 4 -2-SMe)]Fe(η 5 -C 5 H 5 )}Cl] {with M ) Pd (2c) or Pt (3c)}, which are the first examples of cyclopallada-and cycloplatinated compounds containing a mer-terdentate [C(sp 2 , ferrocene), N, S] -ligand. Mössbauer spectroscopic studies and the X-ray crystal structures of 1c-3c are reported. The crystal structures of 2c and 3c confirmed the mode of binding of the ligand and revealed that the molecules are associated in pairs, which interact by C-H‚‚‚π interactions forming a chain that stacks along the [101] plane. Electrochemical studies, based on cyclic voltammetry, reveal that the ease with which the oxidation of the ferrocenyl moiety occurs increases according to the sequence 1c < 2c < 3c. Molecular orbital calculations at a DFT level have also been carried out to rationalize the influence of the nature of the Pd-(II) (in 2c) or Pt(II) in (3c) on the electrochemical properties of these compounds, and theoretical studies using time-dependent density functional theory (TD-DFT) calculations have also been carried out in order to assign the bands observed in the electronic spectra of the cyclometalated compounds.

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The synthesis and characterization of the copper(II) complex [Cu 2 (dpt) 2 {(µ-O 2 C)[(η 5 -C 5 H 4 )Fe(η 5 -C 5 H 5 )]} 2 ](ClO 4 ) 2 (1), where dpt ) dipropylenetriamine, are reported, and its structure was determined by single-crystal X-ray analysis. The compound crystallizes in the monoclinic system, space group P2 1 /n, with a ) 9.920(2) Å, b ) 12.925(2) Å, c ) 15.768(3) Å, β ) 93.17(1)°, and Z ) 2. The cationic part of 1 shows a tetrametallic core in which two ferrocenecarboxylato groups act as (O,O′) bridging ligands between two copper(II) ions with a squarepyramidal environment. Susceptibility measurements on this compound indicate a ferromagnetic, albeit weak, coupling between the two paramagnetic centers, with best-fit values of J ) +2.5(3) cm -1 and g iso ) 2.12(1). Magnetostructural correlations can be qualitatively explained on the basis of the topology of their chairlike core. A quantitative investigation has been performed by means of ab initio density functional theory based calculations in the broken-symmetry approach.

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