Nanoscientists boldly go to the frontiers of the smallest solids in basic science and their technical application. In their Review on H. Goesmann and C. Feldmann point to the visionary potential of nanoparticulate functional materials. After a general introduction of the topic, the optical, electrical, magnetic, and catalytic properties of nanoparticles as well as their potential for upgrading materials are summarized. Moreover, fundamentally novel shapes and compositions of matter are presented.

Nanoparticulate functional materials offer manifold perspectives for the increasing miniaturization and complexity of technical developments. Nanoparticles also make a major contribution to utilization of materials that is sparing of natural resources. Besides these obvious aspects, however, the importance of nanoparticles is due to their fundamentally novel properties and functions. These include photonic crystals and efficient luminophors, single particles and thin films for electronic storage media and switching elements, magnetic fluids and highly selective catalysts, a wide variety of possibilities for surface treatments, novel materials and concepts for energy conversion and storage, contrast agents for molecular biology and medical diagnosis, and fundamentally novel forms and structures of materials, such as nanocontainers and supercrystals. Creating high-quality nanoparticles requires that numerous parameters, involving the particle core and surface, colloidal properties, and particle deposition, are taken into consideration during synthesis of the material. An appropriate characterization and evaluation of the properties requires the incorporation of a wide range of expertise from widely differing areas. These circumstances are what challenges and appeals to the nanoscientist.

The [221] cycloaddition of two alkynes and carbon monoxide in the presence of pentacarbonyliron represents a useful method for the construction of five-membered ring systems. [1, 2] Applications of the resulting tricarbonyl(h 4 -cyclopentadienone)iron complexes to organic synthesis are feasible by demetalation to the free cyclopentadienones. This transformation was achieved by oxidation with trimethylamine Noxide. [1,3] Recently we reported a novel method for the demetalation of tricarbonyl(diene)iron complexes by a photolytically induced exchange of the carbonyl ligands by acetonitrile. [4] Herein we describe an alternative procedure for the ligand exchange at tricarbonyl(h 4 -cyclopentadienone)iron complexes and the subsequent demetalation in the air.Tricarbonyl(h 4 -cyclopentadienone)iron complexes undergo a transformation similar to the Hieber reaction. [5] Thus, reaction of complex 1 a with aqueous NaOH in THF leads to an equilibrium of the corresponding hydrido complexes 2 a and 4 a in a ratio of about 13:1 (Scheme 1). Tricarbonyl(cyclohexa-1,3-diene)iron complexes are inert under these conditions. Addition of H 3 PO 4 affords 2 a in 94 % yield, while reaction with NaH shifts the equilibrium towards the salt 4 a Scheme 1. a) 1m NaOH/THF (1/2); b) C 5 H 11 I; c) H 3 PO 4 ; d) air, daylight, Et 2 O/THF, Na 2 S 2 O 3 , Celite, 3 h; e) NaH, Et 2 O/THF.(82 % yield). Reaction of the hydrido complex 2 a with 1-iodopentane provides the iodo complex 3 a in 98 % yield. A related transformation is reported for the hydrido complex [CpFe(CO) 2 H]. [6] The addition of 1-iodopentane after the reaction of 1 a with NaOH affords an equilibrium of the iodo complexes 3 a and 5 a that is shifted again by addition of H 3 PO 4 or NaH, respectively. Preparation of the iodo complex 3 a without isolation of the intermediate hydrido complex 2 a increases the yield (98 % based on complex 1 a).The 13 C NMR and the IR data of the hydrido complex 2 a and the iodo complex 3 a suggest an h 5 -coordinated hydroxycyclopentadienyl ligand for both compounds. [7] A characteristic structural feature of the hydrido complex 2 a is the unsymmetrical arrangement of the coligands, which is apparent from two CO signals in the 13 C NMR spectrum. This assignment was confirmed by an X-ray structure determination of complex 2 a (Figure 1), [8] which shows an h 5 -coordinated hydroxycyclopentadienyl ligand and a C1ÀO1 bond length of 1.366 . [9] A loss of C S symmetry was also found for the hydrido complex 4 a from the 13 C NMR spectrum, which exhibits the two signals for the carbonyl ligands and a peak at d 170.13 for C1. [7] Figure 1. Molecular structure of 2 a in the crystal. Selected bond lengths []: FeÀC1 2.

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Graphislactones A–H and the structurally related ulocladol are highly oxygenated resorcylic lactones produced by lichens and fungi. We present total syntheses of graphislactones A, C–F, H and of ulocladol. Graphislactones E, F, and H were synthesized for the first time. The spectra of graphislactones E and F synthesized as the originally proposed structures were not in agreement with published data. Consequently, revised structures for these compounds are proposed, whose correctness is unambiguously proven by total synthesis and comparison of the spectroscopic data. Key steps in all syntheses are Suzuki couplings for the construction of the central biaryl bond and Dakin reactions to supply further hydroxy groups required in these highly oxygenated substrates. Graphislactones A, C, and H, acylated graphislactone D and ulocladol were prepared in 8–11 steps with 7–20 % yield starting with purchasable compounds, where the longest linear sequence consists of 5–9 steps. The syntheses are thus significantly shorter than the previously published syntheses of graphislactones A–D and of ulocladol. Graphislactones E and F were synthesized in 8 steps, where the longest linear sequences consist of 6 and 5 steps, respectively. They were isolated as the respective acetylated compounds with 25 and 10 % yield.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)