English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

The first part of this work shows a new application of five-coordinate ruthenium(II) complexes with chelating ligands in fluorination reactions. Organic halides such as chlorides and bromides can be converted to the corresponding fluorides in a nucleophilic substitution with fluoride. The uncatalyzed reaction only works well with greatly activated organic halides such as Ph3CCl and a strong halide scavenger such as AgF or TIF. We now find that complexes of the type [RuF(P-P)2]+ or [RuCl(PNNP)]+ are able to catalyze such reactions and to broaden the scope of potential substrates. K CIN= 0-p/6'p ^-? Ph2 [RuCI2(DAC)] [RuCI2(redDAC)] \=/ Pho [RuCI2(BPA)] =K ÇJ,N=\ Ph2 Ph2x=/ [RuCI2(BNA)] [RuF(dppp)2r [RuCI(dppe)2]+ (S-S)-[RuCI(chiraphos)2]+ For the catalyzed reaction only a moderately activated substrate is required such as a tertiary halide of any kind or a secondary carbon atom with one phenyl substituent. Complete conversion can be achieved within one day with 1 mol% of the catalyst, PhMeCHBr as sub¬ strate, and TIF as source of fluoride, whereas the blank reaction produces less than 1% of the corresponding fluoride. The yield of PhMeCHF in the catalytic reaction is up to 76% as con¬ firmed via GC analysis and NMR spectroscopy. 1-10 mol% + T,F Cata'ySt , ^^ +TICI RT, CH2CI2 One of the P-P and all of the PNNP ligands used are chiral and therefore enantiomerically pure complexes were tested in catalysis. In the case of PNNP = DAC an enantiomeric excess of 13% at 4% conversion was measured, which drops to 3% at full conversion. This result indicates a kinetic resolution of the racemic starting material. The fact that the ee does not drop to 0% can be explained either by the formation of byproducts, which are differently favored in the case of the two enantiomers, or by a slight enantiodiscrimination (face selectiv¬ ity of the free carbocation). The second part of the work deals with the coordination of dioxygen at coordinatively unsaturated 16 electron-complexes of Os(II) of the type [Os(X)(02)(P-P)2]+ with X = CI, Br and with the reduction to the Os(IV) oxo complexes [Os(X)(0)(P-P)2]+. With X = CI and P-P = dcpe all members of the series n = 0, 1 and 2 of [Os(X)(0)n(P-P)2]+ were isolated and fully characterized, including all three crystal structures. Both the dioxygen and the oxo complexes turned out to be surprisingly unreactive, and no productive oxygen transfer could be developed. For all tested substrates, a well-behaved reaction was obtained only with PPh3 and iodide as reducing agent, but with standard organic substrates no reaction could be induced.

repository for publications and research data (eth zurich)

Five-coordinate ruthenium and osmium(II) complexes with chelating phosphine ligands and their application in catalytic fluorination and dioxygen activation