Palladium(0) complexes of diferrocenylmercury diphosphines: synthesis, X-ray structure analyses, catalytic isomerization, and C-Cl bond activation.

Palladium(0) phosphine complexes are of great importance as catalysts in numerous bond formation reactions that involve oxidative addition of substrates. Highly active catalysts with labile ligands are of particular interest but can be challenging to isolate and structurally characterize. We investigate here the synthesis and chemical reactivity of Pd complexes that contain geometrically adaptable diferrocenylmercury-bridged diphosphine chelate ligands (L) in combination with a labile dibenzylideneacetone (dba) ligand.

Diferrocenylmercury diphosphine diastereomers with unique geometries: trans-chelation at Pd(ii) with short Hg(ii)Pd(ii) contacts.

Diphosphine chelate ligands are essential in many catalytic processes with both the electronic structure and bite angle having a dramatic influence on the coordination behavior and catalytic performance. The synthesis of a new class of diferrocenylmercury-supported diphosphine chelate ligands was accomplished by the reaction of (ortho-diphenylphosphino)ferrocenyl sulfinate (2) with t-BuLi, followed by treatment with mercury(ii) chloride. Two diastereomers, 4a (pSpR-, meso-isomer) and 4b (pSpS-isomer), differ in the orientation of the ferrocene moiety relative to the central PhPCH-Hg-CHPPh bridging entity.

Diferrocenylmercury-Bridged Diphosphine: A Chiral, Ambiphilic, and Redox-Active Bidentate Ligand.

A diphosphine chelate ligand with a wide and flexible bite angle, a unique stereochemical environment, and redox-active and ambiphilic character is reported. Initially generated as its HgCl complex by reaction of 1,2-fc(PPh )(SnMe ) (fc=ferrocenediyl) with HgCl in acetone, treatment with [n-Bu N]CN readily liberates the free chiral bidentate ligand. An intermolecular ClHg-Cl→Hgfc (2.

Interplay of Lewis acidity, intramolecular O→Sn interactions and selectivity: organotin-functionalized crown ethers as ditopic hosts for sodium and potassium halides.

The increased Lewis acidity in organotin-functionalized crown ethers XSnCH[19]-crown-6 (5, X = I; 6, X = Br; 7, X = Cl) not only resulted in ditopic complexation of sodium/potassium halides, but also offers an excellent strategy to manipulate through intramolecular O→Sn interactions the selectivity of the crown ether moiety towards Na/K depending on the solvent.

Planar-chiral ferrocenylphosphine-borane complexes featuring agostic-type B-HE (E = Hg, Sn) interactions.

The synthesis of ferrocenylphosphine-borane adducts 1,2-fc(E)(PPh·BH) (E = SnRR', HgX; 1,2-fc = 1,2-ferrocenediyl) that are substituted with organotin or organomercury Lewis acid moieties in ortho-position is presented. Several compounds that feature two ferrocenylphosphine-borane moieties bridged by Sn or Hg are also introduced. The products are fully characterized by multinuclear NMR spectroscopy, high-resolution MALDI-TOF mass spectrometry and elemental analysis.

Liquid membrane transport of potassium fluoride by the organotin-based ditopic host PhFSnCHSnFPh-CH-[19]-crown-6.

The extraction of KF from aqueous media and transport through an organic membrane is extremely challenging owing to the high hydration energies of especially the F anions. A novel organotin-based ditopic host containing the PhFSnCHSnFPh-CH-moiety (selective for fluoride anion complexation) covalently linked to 19-crown-6 (selective for potassium cation complexation) is reported. It transports KF up to 5.

How big is a Cp? Novel cycloheptatrienyl zirconium complexes with tri-, tetra- and pentasubstituted cyclopentadienyl ligands.

The new bulky cyclopentadienyl anions 1,2,4-tri(cyclopentyl)cyclopentadienide and 2,3-diisopropyl-1,4-dimethyl-5-trimethylsilyl-cyclopentadienide were prepared. These and the already known 1,2,4-tri(cyclohexyl)-, 1,2,4-tri(isopropyl)-, 2,3-diisopropyl-1,4-dimethyl-, 1,3,4-triisopropyl-2,5-dimethyl-, pentaphenyl-, and p-butylphenyl-tetraphenyl-cyclopentadienide as well as tert-butylindenide were coordinated to the cycloheptatrienylzirconium fragment [(CHT)ZrCl(tmeda)]. The nine zirconium complexes of the [(CHT)Zr(Cp)] type were characterized by elemental analysis and NMR spectroscopy.

The first examples of a crown ether intramolecularly encapsulating mono- and diorganotin dications: synthesis and structures of [PhSnCH2([16]crown-5)][ClO4]2 and [HOSnCH2([16]crown-5)][Y]2 (Y=ClO4, CF3SO3).

The reaction of silver perchlorate with [PhI(2)SnCH(2)([16]crown-5)] (1) and [I(3)SnCH(2)([16]crown-5)] (2) gave the organotin(IV)-substituted crown ether complexes [PhSnCH(2)([16]crown-5)][ClO(4)](2) (3) and [HOSnCH(2)([16]crown-5)][Y](2) (4: Y=ClO(4), 5: Y=CF(3)SO(3)), respectively. All compounds have been isolated as air-stable materials and characterised by (1)H, (13)C, (119)Sn and (119)Sn MAS (5) NMR spectroscopy, ESIMS spectrometry, elemental analysis and by single-crystal X-ray diffraction analysis. The molecular structures of 3-5 show that the tin(IV) cation fits perfectly into the crown ether cavity and is coordinated by the five oxygen atoms of the ring to give a pentagonal bipyramidal configuration about the central metal cation.