Bis(η5-cyclopentadienyl)(2-{[(2-methoxyphenyl)imino]methyl}phenolato-κ3 O,N,O′)terbium

The air- and moisture-sensitive title compound, [Tb(C5H5)2(C14H12NO2)], was synthesized from tris(cyclopentadienyl)(tetrahydrofuran)terbium and 2-{[(2-methoxyphenyl)imino]methyl}phenol. Each Tb atom is coordinated by two cyclopentadienyl ligands in an η5-coordination mode and by one N and two O atoms of the organic ligand in a tridentate κ3 O,N,O′-mode.

Syntheses and Characterization of the First Cycloheptatrienyl Transition-Metal Complexes with a M-CF3 Bond

The organometallic chemistry of metal complexes with organocyclic ligands of higher than five hapticity is much more lacking than the chemistry of metal complexes with η5-cyclopentadienyl ligands, which has been explored in considerable depth, resulting in novel advances. The main reason for this is stability. In particular, reports indicate that (η7-C7H7)MLn complexes are considerably less stable than analogous (η5-C5H5)MLn. In perfluoroalkyl metal chemistry, there is currently no reported (η7-C7H7)MLn derivative, whereas a number of alkylated ones are known and important conclusions have been drawn about their stability. Responding to this void, and using Morrison’s trifluoromethylating reagent, the present study reports the synthesis and characterization of the first cycloheptatrienyl molybdenum complexes bearing the trifluoromethyl moiety; (η7-C7H7)Mo(CO)2CF3 (I), and (η7-C7H7)Mo(CO)(PMe3)CF3 (II) and discusses their low thermal instability.

Lipase Immobilized on MCFs as Biocatalysts for Kinetic and Dynamic Kinetic Resolution of sec-Alcohols

Dynamic kinetic resolution (DKR) is one of the most attractive methods for enantioselective synthesis. In the reported studies, lipase B from Candida antarctica (CALB) immobilized on siliceous mesoporous cellular foams (MCF) functionalized with different hydrophobic groups, and two ruthenium complexes with substituted cyclopentadienyl ligands were investigated as catalysts for the chemoenzymatic DKR of (rac)-1-phenylethanol, using Novozym 435 as a benchmark biocatalyst. Studies on the (rac)-1-phenylethanol transesterification reaction showed that CALB supported on MCFs grafted with methyl groups is a promising biocatalyst and isopropenyl acetate is a preferable acylation agent. Both Ru-complexes activated by K3PO4 or t-BuOK, proved to be effective catalysts of the racemization reaction. The final DKR experiments using all catalysts combinations singled out, gave 96% conversion, and (R)-1-phenylethyl acetate enantiomeric excess of 98% in 8 h using K3PO4 activator.

CpxM(III)-Catalyzed Enantioselective C–H Functionalization through Migratory Insertion of Metal-Carbenes/Nitrenes

CpxM(III)-catalyzed enantioselective C−H functionalization reactions have progressed rapidly using either chiral cyclopentadienyl ligands or appropriate chiral carboxylic acids. In this context, highly reactive carbene and nitrene precursors can be served...