Massimiliano Valentini

Synthesis of Ru–Arene complexes of Me-Duphos. X-ray, PGSE NMR diffusion and catalytic studies

Abstract Cationic [RuCl(arene)(Me-Duphos)]Cl complexes, arene=η6-benzene and η6-p-cymene, Me-Duphos=1,2-bis-((2R,5R)-2,5-dimethylphospholano) benzene) have been prepared and studied by X-ray crystallography and NMR spectroscopy. PGSE NMR diffusion studies have been used to recognize (a) ion pairing as a function of solvent and (b) larger molecular volumes. Several arene–Ru-complexes have been shown to be useful catalyst precursors in the hydrolysis of terminal aryl alkynes to afford acetophenones.

Selective dynamics of [Rh(1,5-COD)(bidentate)]BF4 complexes via NMR exchange spectroscopy

NMR exchange measurements on [Rh(1,5-COD)(bidentate)]BF 4 complexes (bidentate=chiral bis-phosphine, a P,N-phosphino-oxazoline, a P,S-phosphito-thioether and a bis-pyrazolylborate) show selective 1,5-COD dynamics which can be superficially attributed to olefin rotation. It is suggested that the mechanism actually involves: (i) ML 1 bond breaking (L 1 =N or S-donor); (ii) isomerization of the T-shaped species; (iii) rotation around the remaining ML 2 bond and (iv) recomplexation. The solid state structures of the two compounds [M(1,5-COD)( 10 )]BF 4 , M=Rh, Ir and 10 =( S,R )-2-[4-(isopropyl)oxazol-2-yl]-2′-diphenylphosphino-1,1′-binaphthyl, were determined by X-ray diffraction methods.

Röntgenstrukturanalyse, Diffusionsmessungen und NOESY‐NMR‐Untersuchungen chiraler, vierkerniger CuI‐Katalysatoren aus einzähnigen Thiol‐Derivaten von TADDOL

Die stabilen chiralen CuI-Katalysatoren1 (X=OH, OMe, NMe2) enthalten sowohl in Losung als auch im Festkorper die Thiol-TADDOL-Derivate unerwartet einzahnig koordiniert. Zum ersten Mal wurde die Aggregation von Organokupferkomplexen durch NMR-Diffusionsmessungen bestimmt. NOESY-NMR-Messungen an einem Isonitril-Cu-Modellkomplex ergaben, dass die Konformation der TADDOL-Einheit von der Art der zweiten potentiellen Donorgruppe abhangt. TADDOL=α,α,α′,α′-Tetraaryl-2,2-dimethyl-1,3-dioxolan-4,5-dimethanol.