The need for efficient, tailor-made catalysts has inspired chemists to fuse the design principles of natural enzymes with synthetic macromolecular architectures. A highly interesting pathway mimics a metallo-enzyme's tertiary structure via the target placement of metal-ions in a tailor-made polymeric framework, resulting in catalytically active single-chain nanoparticles. Initial studies reveal unusual and promising effects, regarding both new catalyst characteristics and a high impact on product formation. These multifunctional nanoreactors, constructed from simple folded polymer chains, will lead to advanced bioinspired catalytic systems. As found in enzymes, their impact lies specifically within the defined construction of a polymeric pocket around the catalytic active cores for substrate recognition.

A pentanuclear dysprosium hydroxy cluster of composition [Dy 5(mu 4-OH)(mu 3-OH) 4(mu-eta (2)-Ph 2acac) 4(eta (2)-Ph 2acac) 6] ( 1; Ph 2acac = dibenzoylmethanide) was prepared starting from [DyCl 3.6H 2O] and dibenzoylmethane. Both static (dc) and dynamic (ac) magnetic properties of 1 have been studied. Below 3 K, the appearance of slow relaxation of the magnetization typical for single-molecule magnets is seen, even if no hysteresis effects on the M vs H data are observed above 1.8 K.

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Methyltrioxorhenium(vii) (MTO) forms trigonal-bipyramidal adducts with pyridines and related Lewis bases. These complexes have been isolated and fully characterized, and two single-crystal X-ray structures are reported. The complexes react with H 2 O 2 to form mono-and bisperoxo complexes which were examined in situ by 1 H and 17 O NMR spectroscopy. A clear increase in electron deficiency at the Re center can be observed from the MTO complexes to the bisperoxo complexes in all cases examined. The activity of the bisperoxo complexes in olefin epoxidation depends on the Lewis bases, the redox stability of the ligands, and the excess of Lewis base used. Density functional calculations show that when the ligand is pyridine or pyrazole there are significantly stabilized intermediates and moderate energies of the transition states in olefin epoxidation. This ultimately causes an acceleration of the epoxidation reaction. In contrast, the catalytic performance is reduced when the ligand was a nonaromatic nitrogen base. The frontier orbital interaction between the olefin HOMO p(C ± C) and orbitals with s*(O ± O) character in the LUMO group of the Re-peroxo moiety controls the olefin epoxidation.

Sodium and potassium cyclopentadienide were obtained in an improved synthetic procedure. They were prepared in a one-pot synthesis directly by reaction of alkali metals with neat dicyclopentadiene at elevated temperature. The products precipitated as white powders and were isolated by filtration. The excess of dicyclopentadiene can be recycled. The new reaction procedure provides a much more convenient access to the products, no dry solvents such as THF or decahydronaphthalene are needed, and no colored impurities are observed.

The air- and moisture-stable pentanuclear yttrium cluster H(5)[Y(5)(mu(4)-O)(mu(3)-O)(4)(mu-eta](2)-Ph(2)acac)(4)(eta](2)-Ph(2)acac)(6)](Ph(2)acac = dibenzoylmethanide) has been used as a homogeneous catalyst for the oxidation of aldehydes to the corresponding carboxylic acids in the presence of air.

The Schiff base compound 2,2'-{[(2-aminoethyl)imino]bis[2,1-ethanediyl-nitriloethylidyne]}bis-2-hydroxy-benzoic acid (H(4)L) as a proligand was prepared in situ. This proligand has three potential coordination pockets which make it possible to accommodate from one to three metal ions allowing for the possible formation of mono-, di-, and trinuclear complexes. Reaction of in situ prepared H(4)L with Dy(NO(3))(3)·5H(2)O resulted in the formation of a mononuclear complex [Dy(H(3)L)(2)](NO(3))·(EtOH)·8(H(2)O) (1), which shows SMM behavior. In contrast, reaction of in situ prepared H(4)L with Mn(ClO(4))(2)·6H(2)O and Dy(NO(3))(3)·5H(2)O in the presence of a base resulted in a trinuclear mixed 3d-4f complex (NHEt(3))(2)[Dy{Mn(L)}(2)](ClO(4))·2(H(2)O) (2). At low temperatures, compound 2 is a weak ferromagnet. Thus, the SMM behavior of compound 1 can be switched off by incorporating two Mn(II) ions in close proximity either side of the Dy(III). This quenching behavior is ascribed to the presence of the weak ferromagnetic interactions between the Mn(II) and Dy(III) ions, which at T > 2 K act as a fluctuating field causing the reversal of magnetization on the dysprosium ion. Mass spectrometric ion signals related to compounds 1 and 2 were both detected in positive and negative ion modes via electrospray ionization mass spectrometry. Hydrogen/deuterium exchange (HDX) reactions with ND(3) were performed in a FT-ICR Penning-trap mass spectrometer.

The preparation and in-depth characterization of well-defined, palladium(ii) crosslinked single-chain nanoparticles (Pd-SCNPs) is reported. In addition, a novel procedure for interpreting the SEC chromatograms of SCNPs by log-normal distribution (LND) simulations is introduced.