Cluster Formation of Self-Assembled Triarylbismuthanes and Charge Transport Characterizations of Gold-Triarylbismuthane-Gold Junctions.

Organometallic molecules are promising for molecular electronic devices due to their potential to improve electrical conductance through access to complex orbital covalency that is not available to light-element organic molecules. However, studies of the formation of organometallic monolayers and their charge transport properties are scarce. Here, we report the cluster formation and charge transport properties of gold-triarylbismuthane-gold molecular junctions.

Hypervalent organobismuth complexes: pathways toward improved reactivity, catalysis, and applications.

Hypervalent (three-center, four-electron) bonding in organobismuth complexes has been extensively studied due to its ability to affect molecular geometry, dynamic behavior, or to stabilize the ligand scaffold. This work addresses the effects of this bonding on reactivity, catalytic activity, redox processes, and its potential applications in biosciences, materials science, and small molecule activation.

Synthesis of Chiral Hypervalent Trifluoromethyl Organobismuth Complexes and Enantioselective Olefin Difluorocarbenation Screenings.

Two hypervalent trifluoromethyl organobismuth complexes were prepared from commercially available chiral amines, (R)-1-cyclohexylethylamine and (1R, 2R, 3R, 5S)-(-)-isopinocampheylamine; however, only the complex from the latter amine was prepared as a single stereoisomer. Both organobismuth complexes were fully characterized by NMR spectroscopy and single-crystal X-ray crystallography, revealing that the structures were similar to previously reported complexes with a hypervalent Bi-N bond. The complexes were catalytically active in olefin difluorocarbenation with Ruppert-Prakash reagent (TMS-CF ) used as a terminal source of CF .

Trimerization and cyclization of reactive P-functionalities confined within OCO pincers.

In order to stabilize a 10-P-3 species with symmetry and two lone pairs on the central phosphorus atom, a specialized ligand is required. Using an NCN pincer, previous efforts to enforce this planarized geometry at P resulted in the formation of a -symmetric, 10π-electron benzazaphosphole that existed as a dynamic "bell-clapper" in solution. Here, OCO pincers 1 and 2 were synthesized, operating under the hypothesis that the more electron-withdrawing oxygen donors would better stabilize the 3-center, 4-electron O-P-O bond of the 10-P-3 target and the sp-hybridized benzylic carbon atoms would prevent the formation of aromatic P-heterocycles.

Molybdenum chloride catalysts for Z-selective olefin metathesis reactions.

The development of catalyst-controlled stereoselective olefin metathesis processes has been a pivotal recent advance in chemistry. The incorporation of appropriate ligands within complexes based on molybdenum, tungsten and ruthenium has led to reactivity and selectivity levels that were previously inaccessible. Here we show that molybdenum monoaryloxide chloride complexes furnish higher-energy (Z) isomers of trifluoromethyl-substituted alkenes through cross-metathesis reactions with the commercially available, inexpensive and typically inert Z-1,1,1,4,4,4-hexafluoro-2-butene.

A Masked Phosphinidene Trapped in a Fluxional NCN Pincer.

The trapping of a phosphinidene (R-P) in an NCN pincer is presented. Stabilized phosphinidene 1 was characterized by P{ H}, H, and C{ H} NMR spectroscopy, exhibiting an averaged C symmetry in solution between -60 and 60 °C. In the solid state, the phosphinidene is coordinated by one adjacent N atom featuring a formal P-N bond (1.

Synthesis of Molybdenum and Tungsten Alkylidene Complexes That Contain Sterically Demanding Arenethiolate Ligands.

Imido alkylidene complexes of Mo and W and oxo alkylidene complexes of W that contain thiophenoxide ligands of the type S-2,3,5,6-PhCH (STPP) and S-2,6-(mesityl)CH (SHMT = S-hexamethylterphenyl) have been prepared in order to compare their metathesis activity with that of the analogous phenoxide complexes. All thiolate complexes were significantly slower (up to ∼10× slower) for the metathesis homocoupling of 1-octene or polymerization of 2,3-dicarbomethoxynorbornene, and none of them was -selective. The slower rates could be attributed to the greater σ-donating ability of a thiophenoxide versus the analogous phenoxide and consequently a higher electron density at the metal in the thiophenoxide complexes.

Mass spectrometric studies of reductive elimination from Pd(IV) complexes.

Reductive elimination of ethane from the palladium(IV) complex [PdMe3(bpy)I] (bpy = 2,2'-bipyridine) is studied by electrospray ionization mass spectrometry. Palladium(IV) complexes can be detected as binuclear clusters [Pd2Me6I(bpy)2](+) or as complexes [PdMe3(bpy)(L)](+) stabilized by an electron-donating ligand L. Fragmentation of all palladium(IV) complexes is dominated by elimination of ethane which corresponds to the reductive elimination coupling of the methyl groups.

Mechanistic insights into a copper-disulfide interaction in oxidation of imines by disulfides.

The concept of using disulfides as an oxidant for Cu(i) is introduced as part of a Cu-catalyzed process leading to the formation of benzothiazole from an iminodisulfide under an inert atmosphere.