A new type of Cp‘−P ligand (the third generation of the Cp‘−P ligand), [{3-(NM)Ind−P} n =2]H (3a), in which an indenyl group, having a neomenthyl group, and a diphenylphosphino group are connected by an ethylene group, was designed and prepared. The presence of the two kinds of chiralities, indenyl-based planar chirality and stereogenic centers of the neomenthyl group, was an indispensable factor for inducing high stereoselectivity around the metal center.

We have shown concrete evidence for migration of an alkyl group in carbonyl insertion and deinsertion steps between the methyl carbonyl rhodium complex [{η 5 :η 1 -(Ind-P) n)3 }Rh(CO)Me]BF 4 (3) and the acetyl rhodium complex {η 5 :η 1 -(Ind-P) n)3 }RhI(COMe) (1) by crystallography as well as by 1 H NMR spectroscopy.

Treatment of [RuCl2(η6-C6H6)]2 with 1,2-bis(diphenylphosphino)benzene (abbreviation DPB) led to [RuCl(η6-C6H6)(dpb)]Cl (2). When complex 2 in methanol was heated at 50 °C for 13 h, a cationic trinuclear complex [Ru3(μ2-Cl)3(μ3-Cl)2(dpb)3]Cl (3a) was obtained in 75% yield with liberation of the benzene ligand. The cationic trinuclear structure was confirmed by X-ray analysis of [Ru3Cl5(dpb)3]PF6 (3b). Three ruthenium atoms were linked by three μ2-bridging chloride atoms and two face-capped μ3-chloride atoms to form a triangular core of Ru3(μ2-Cl)3(μ3-Cl)2.

We found the first ring methyl activation of an η 4 -cyclobutadiene complex. Base-promoted ring methyl activation of the cyclobutadiene-palladium(II) complex [PdCl 2 (η 4 -C 4 Me 2 ( t Bu) 2 )] 2 (2) in the presence of triethylamine afforded the dinuclear exo-methylene-η 3 -cyclobutenyl complex [PdCl(η 3 -C 4 (dCH 2 )Me( t Bu) 2 )] 2 (3) in 81% yield. In the case of pyridine as base, a mixture of 3 and [C 5 H 5 NH][PdCl 3 (η 4 -C 4 Me 2 ( t Bu) 2 )] (4) was obtained. The complex 4 was alternatively derived from the reaction of 2 with 2 equiv of C 5 H 5 N‚HCl. The ring methyl activation of 2 in the presence of 2,2′-bipyridine and triethylamine followed by treatment with AgBF 4 led to the formation of the cationic complex [Pd(η 3 -C 4 (d CH 2 )Me( t Bu) 2 )(bipy)]]BF 4 (6) in 83% yield. The mononuclear exo-methylene-η 3 -cyclobutenyl structure of 6 was confirmed by spectral data and a crystallographic study.

Until now, no three-dimensional structural data of the 'especially bad' small dense (sd-LDL) particles existed. Our previously published X-ray structure [Lunin et al. 2001] and the one obtained by Orlova et al. [1999] (cryo EM) correspond to the larger LDL-2 particles. Both papers showed that LDL particles have a cylindrical respectively ellipsoidal shape and are not spherical particles as commonly assumed. In the particle core, a system of flat layers was observed. At present, we are able to grow crystals of native, human LDL particles from all LDL subfractions, except LDL-4. Whereas LDL-1 to LDL-3 (large LDL) crystallize in space group C2, LDL-5 and LDL-6 (sd-LDL) crystallize in space group P2(1). By special methods we were able to collect 100% complete datasets of LDL crystals in a resolution range of 300-27A. A simple analysis of the parameters of the reduced cells shows that large-LDL and sd-LDL differ predominantly in the short axis of the crystallographic unit cell (large-LDL: a=180 Å, sd-LDL: a=143 Å). These results lead to the hypothesis that sd-LDL particles, if approximated as cylinders, have a height reduced by 37 Å compared to large-LDL. As the repeating distance of smectic layers of LDL cholesterol esters is also 37 Å, the observed reduction of one cell axis could correspond well to the disappearance of one layer of cholesterol esters in the particle core. This is perfectly supported by the now available electron density maps calculated from LDL-5 and LDL-6 datasets by ab initio methods were in fact the disappearance of one layer inside the particle core is visible. While differences in core structure are obvious, the analysis of the particle surface (ApoB fold) is more complicated due to the dense packing of the crystals, and still in progress.