A series of [2,6-bis(2-benzimidazolyl)pyridyl]chromium chlorides have been synthesized and characterized by elemental analysis and IR spectroscopy, along with X-ray diffraction analysis for the structures of C1 and C7. When methylaluminoxane (MAO) was employed as the cocatalyst, the chromium complexes showed high activity for ethylene oligomerization and polymerization. Oligomers were produced with high selectivity for α-olefins, and polyethylenes were generated with extremely broad molecular weight distributions. In the presence of diethylaluminum chloride (Et2AlCl), these chromium complexes showed moderate activity for ethylene polymerization and produced high-molecular-weight linear polyethylene.

Electrochemical oxidation of 2,4‐dimethylphenol directly provides pentacyclic systems being generated by an oxidative trimerization. The major pentacyclic scaffold is exclusively formed as a single diastereoisomer and is easily isolated. Three further pentacyclic compounds which occur in minor quantities were also fully characterized including their solid‐state structures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

We report a generally applicable method to pattern organic molecules on mesoscopic scales. In our method, organic molecular beam deposition was conducted on substrate surfaces prepatterned with materials to which the organic molecules have larger binding energies in comparison to the substrate. Fully uniform nucleation control at these predefined locations can be achieved by an appropriate selection of the growth parameters including temperature and deposition rate. The physical mechanisms involved are studied by Monte Carlo simulations and stand in good agreement with the experimental findings.

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A series of C 1 -bridged Cp/amido group 4 metal complexes [("CpCN")MX 2 ] was prepared. The starting compound 6-tert-butylfulvene (7) was reacted with LiNHR (R ) o-anisyl (a), p-anisyl (b), phenyl (c), or tert-butyl (d)) to yield the Li(C 5 H 4 -CH(tBu)-NHR) compounds (8). Subsequent deprotonation with n-butyllithium, followed by transmetalation with Cl 2 -Ti(NMe 2 ) 2 , yielded the ("CpCN")Ti(NR 2 ) 2 complexes 10 (a-d). A second synthetic series started from 6-(dimethylamino)fulvene ( 11). The reaction with the LiNHR reagents led to addition followed by HNMe 2 elimination to yield the respective imino-substituted cyclopentadienides Li(C 5 H 4 -CHdNR) (13). Addition of methyllithium to 13 gave the (Li + ) 2 (C 5 H 4 -CHMe-NR) 2-, ("CpCN") 2-, ligands (14). Transmetalation with Cl 2 Ti(NMe 2 ) 2 subsequently yielded the corresponding µ-CHMe-bridged Cp/amido group 4 complexes 15 (a-c). Treatment with Me 2 SiCl 2 cleanly converted the ("CpCN")M(NR 2 ) 2 complexes to the respective ("CpCN")-MCl 2 systems [3a-d, 4a-c (Ti), 5a (Zr)]. These were transformed to the ("CpCN")M(CH 3 ) 2 complexes [µ-CHCMe 3 : 17a-d (Ti), 19a (Zr), µ-CHMe: 18a-c (Ti)] and the (s-cis-supineη 4 -butadiene)("CpCN")Ti systems 21a-d and 22b,c. With respect to X-ray structure analyses the (CpCN)MX 2 systems must be regarded as more "constrained" than their ("CpSiN")MX 2 analogues. The ("CpCN")MCl 2 and ("CpCN")M(CH 3 ) 2 complexes were used as catalysts for ethene homopolymerization and ethene/1-octene copolymerization. All systems gave active catalysts, but these were quite different in their catalytic performance when compared with the usually applied ("CpSiN")TiX 2 -derived catalysts. The ("CpCN")M catalyst activities and selectivities were very dependent on the specific activator components employed.

A series of unsaturated long-chain-bridged diferrocenes Fc-(CH2)n-CH=CH-(CH2)n-Fc (4 a-e) was synthesized by means of olefin metathesis. Subsequent catalytic hydrogenation furnished the saturated alpha,omega-bis-ferrrocenyl oligoethylene products Fc-(CH2)m-Fc (5). Members of both series formed highly ordered laminar structures at the highly oriented pyrolytic graphite (HOPG) solid/liquid interface or on the Ag(110) surface, which were characterized by STM. Details of the structural features of these ordered physisorbed surface assemblies of 4 and 5 were analyzed by comparison with DFT calculations on model systems and with the characteristic packing modes of these systems in the crystal.

A strategy for designing and activating surface-mounted molecular rotors with variable rotation radii and functional groups is proposed and demonstrated. The key point of the strategy is to separate the anchor and the rotating functional group from each other by using a connector of adjustable length. The three independent parts of the molecule are responsible for different functions to support the rotating movement of the molecule as a whole. In this way, one can easily change each part to obtain molecular rotors with different sizes, anchors, and functional rotating groups.

A series of nickel complexes ligated by N-((pyridin-2-yl)methylene)quinolin-8-amine derivatives were synthesized by one-pot reaction of 8-aminoquinolines, 1-(pyridine-2-yl) ketones, and nickel halides and characterized by elemental and spectroscopic analyses along with X-ray diffraction analyses. These nickel complexes exhibit two kinds of structures, namely, dimeric with octahedral-coordinated geometry and monomeric with distorted trigonal-bipyramidal geometry, in their solid states. Activated by Et 2 AlCl, these Ni(II) complexes exhibited good to high catalytic activities for ethylene oligomerization, and activity up to 4.9 × 10 7 g mol -1 (Ni) h -1 was observed in the catalytic system with Cy 3 P as auxiliary ligand. The steric and electronic influence of the substituents as well as the influence of different catalytic conditions was carefully investigated. In particular, the correlations between reactivity and auxiliary R 3 P ligands were examined.