A mass-tagged N-mesityl imidazolinium salt with four additional -CH(2)NCy(2) substituents was synthesized, leading to a molecular mass of nearly 1100 g mol(-1) in the corresponding carbene ligand. This mass-tagged ligand was used to generate the respective Grubbs II and Grubbs-Hoveyda type complexes. The catalytic activity of the latter complex was tested in several olefin metathesis reactions and found to be slightly superior to that of the related N-mesityl based complex. In batchwise solvent resistant nanofiltration experiments the ruthenium complex dissolved in toluene and following a metathesis reactions was efficiently retained (>99.8 %) by a single nanofiltration; the permeate contained less than 4 ppm of Ru. Equally efficient catalyst retention was observed in a membrane reactor utilized for the continuous synthesis of a RCM product.

Fluorophore tagged N-heterocyclic carbenes and the derived (NHC)Pd(allyl)Cl complexes were synthesized and the fluorescence signal was used to follow the course of a Suzuki coupling reaction.

An enlarged imidazolinium salt with a molecular mass of nearly 800 g/mol was synthesized and the respective N-heterocyclic carbene (NHC= N,N′-bis(2,6-diisopropyl-4-CH2NCy2-phenyl)-4,5-dihydroimidazol-2-ylidene) converted into (NHC)Pd(allyl)Cl and (NHC)Pd(cinnamyl)Cl complexes. The cinnamyl complex displays excellent activities in the Suzuki−Miyaura coupling and the Buchwald−Hartwig amination. The separation of this complex from the coupling products by means of a solvent-resistant nanofiltration using a PDMS (polydimethylsiloxane) membrane on PAN (polyacrylonitrile) was tested, and very high retention of between 97% and 99.9% of the (NHC)Pd complex was observed. The residual Pd content in the cross-coupling products is in the range 3.5−25 ppm.

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Catalysis O 0020Fluorophore Tagged Cross-Coupling Catalysts. -Two novel fluorophore tagged NHC palladium complexes (I) are prepared and applied as catalysts in Suzuki coupling reactions (yields not given). The fluorescence signal allows to follow the course of the Suzuki coupling reaction. -(SASHUK, V.; SCHOEPS, D.; PLENIO*, H.; Chem.