Versatile Coordination of Cyclopentadienyl-Arene Ligands and Its Role in Titanium-Catalyzed Ethylene Trimerization

Cationic titanium(IV) complexes with ansa-(η5-cyclopentadienyl,η6-arene) ligands were synthesized and characterized by X-ray crystallography. The strength of the metal-arene interaction in these systems was studied by variable-temperature NMR spectroscopy. Complexes with a C1 bridge between the cyclopentadienyl and arene moieties feature hemilabile coordination behavior of the ligand and consequently are active ethylene trimerization catalysts. Reaction of the titanium(IV) dimethyl cations with CO results in conversion to the analogous cationic titanium(II) dicarbonyl species. Metal-to-ligand backdonation in these formally low-valent complexes gives rise to a strongly bonded, partially reduced arene moiety. In contrast to the η6-arene coordination mode observed for titanium, the more electron-rich vanadium(V) cations [cyclopentadienyl-arene]V(NiPr2)(NC6H4-4-Me)+ feature η1-arene binding, as determined by a crystallographic study. The three different metal-arene coordination modes that we experimentally observed model intermediates in the cycle for titanium-catalyzed ethylene trimerization. The nature of the metal-arene interaction in these systems was studied by DFT calculations.

Methodology for Y Chromosome Capture: A complete genome sequence of Y chromosome using flow cytometry, laser microdissection and magnetic streptavidin-beads

This study is a comparison of the efficiency of three technologies used for Y chromosome capture and the next-generation sequencing (NGS) technologies applied for determining its whole sequence. Our main findings disclose that streptavidin–biotin magnetic particle-based capture methodology offers better and a deeper sequence coverage for Y chromosome capture, compared to chromosome sorting and microdissection procedures. Moreover, this methodology is less time consuming and the most selective for capturing only Y chromosomal material, in contrast with other methodologies that result in considerable background material from other, non-targeted chromosomes. NGS results compared between two platforms, NextSeq 500 and SOLID 5500xl, produce the same coverage results. This is the first study to explore a methodological comparison of Y chromosome capture and genetic analysis. Our results indicate an improved strategy for Y chromosome research with applications in several scientific fields where this chromosome plays an important role, such as forensics, medical sciences, molecular anthropology and cancer sciences.Spanish Alfonso Martin Escudero Foundation for the financial support to one of the authors of the present work (MJ Alvarez –Cubero)

C–H Functionalization Reactivity of a Nickel–Imide

This article discusses C-H functionalization reactivity of a Nickel-Imide

First Results on Growth Rates of the Endophytic Fungi Acremonium and Epichloe on Solid and Liquid Media

Growth rates of the ·grass endophytes Acrenonium lolii Latch, Christensen and Samuels, A. coenoplrialiim Morgan-Jones lind Garns and Epichloe typhina\u27 (Fries) Tulasne were measured on different solid media under various conditions and in liquid medium. A. coenophiallum and E. ryphina developed best vegetative growth at 25°C in the dark ori;pofato-dextrose-ilgar (PDA) and on minimal­medium (MM), respectively. A: lo/ii grew best at 2coenophialum and E. typhina produced 1.48 g and 6 g FW, respectively. Within 3 days the conductivit)\u27. reached constant values.· Osmolarity decreased with the increase of biomass. pH rose in cultures of A. lolii and E. typhina from 5 to 7.5 and from 5 to 6.9 respectively, but decreased in cultures of A. coenophialum from 5 to 4. I