Four (2,2'-bipyridyl)(ferrocenyl)boronium derivatives.

Crystal structures are reported for four (2,2'-bipyridyl)(ferrocenyl)boronium derivatives, namely (2,2'-bipyridyl)(ethenyl)(ferrocenyl)boronium hexafluoridophosphate, [Fe(C5H5)(C17H15BN2)]PF6, (Ib), (2,2'-bipyridyl)(tert-butylamino)(ferrocenyl)boronium bromide, [Fe(C5H5)(C19H22BN3)]Br, (IIa), (2,2'-bipyridyl)(ferrocenyl)(4-methoxyphenylamino)boronium hexafluoridophosphate acetonitrile hemisolvate, [Fe(C5H5)(C22H20BN3O)]PF6·0.5CH3CN, (IIIb), and 1,1'-bis[(2,2'-bipyridyl)(cyanomethyl)boronium]ferrocene bis(hexafluoridophosphate), [Fe(C17H14BN3)2](PF6)2, (IVb). The asymmetric unit of (IIIb) contains two independent cations with very similar conformations.

A new weakly coordinating aluminate anion incorporating a chelating perfluoro-bis-anilido ligand.

The synthesis of the fully fluorinated bis-anilido ligand N,N'-bis-pentafluorophenyl-3,4,5,6-tetrafluorophenylene-1,2-diamine, 1 is described. Reaction of one or two equivalents of 1 with AlMe(3) gives aluminium compounds incorporating one or two ligands, the latter being the protonated form of a new weakly coordinating anion (WCA), 3-H. Alternatively, reaction of 1 with LiAlH(4) yields the lithium salt of this anion, 3-Li, which may be employed as a reagent for preparing the trityl and N,N-dimethylanilinium salts of the aluminate anion.

The silicate-mediated formose reaction: bottom-up synthesis of sugar silicates.

Understanding the mechanism of sugar formation and stabilization is important for constraining theories on the abiotic origin of complex biomolecules. Although previous studies have produced sugars from small molecules through the formose and related reactions, the product mixtures are complex and unstable. We have demonstrated that simple two- and three-carbon molecules (glycolaldehyde and glyceraldehyde), in the presence of aqueous sodium silicate, spontaneously form silicate complexes of four- and six-carbon sugars, respectively.

[Simultaneous determination of platinum (IV) and palladium (II) using spectrophotometry method].

The N-(m-methylphenyl)-N'-(sodium p-aminobenzenesulfonate)-thiourea (MMPT) was good reagent of water solubility. In the medium of an HAc-NaAc buffer solution and hexadecyltrimethylammonium bromide (CTMAB), MMPT can react with platinum (IV) and palladium (II) to form green and brown soluble complex. The maximum absorbance of the complex was at lambdaPt(max) = 754.

Synthesis of calixarene-capped carbosilane dendrimers.

A new class of polycalix[4]arene hosts has been constructed based on a carbosilane dendrimer architecture, in which each dendritic branch terminates with a calix[4]arene entity. This study reports the synthesis and characterization of the zeroth generation example with four calix[4]arenes and of the first generation example with 12 calix[4]arenes.

Competitive ArC-H and ArC-X (X = Cl, Br) activation in halobenzenes at cationic titanium centers.

The titanium methyl cation [Cp*((tBu3P=N)TiCH3]+ [B(C6F5)4]- reacts rapidly with H2 to give the analogous cationic hydride [Cp*((tBu3P=N)TiH(THF)n]+ [B(C6F5)4]- (n = 0, 1), which can be trapped and isolated as its THF adduct 1 x THF (n = 1). When generated in the presence of chloro or bromobenzene, 1 undergoes C-X activation or ortho-C-H activation, depending on the amount of dihydrogen present in the reaction medium. At approximately 4 atm of H2, C-X activation is preferred, giving the halocations [Cp*((tBu3P= N)TiX]+ [B(C6F5)4]- (2X) and C6H6/biphenyl mixtures.

Isolation and characterization of a monomeric cationic titanium hydride.

Methyl cations 1-Cp and 1-Cp*, stabilized by the tri-tert-butylphophinimine ligand and either C5H5 or C5Me5, were generated from the neutral dimethyl precursors and [Ph3C]+[B(C6F5)4]-. Reaction of these compounds with H2 resulted in contrasting reactions. For 1-Cp, hydrogenolysis of the Ti-CH3 group led to rapid reduction to Ti(III) and production of a cationic Ti(III) dimer, 2, presumably formed upon loss of H2 from a transiently generated Ti(IV) hydride.

Isomorphism and phase transition in triferrocenylboroxine and triferrocenylborazine.

The crystal structures of triferrocenylboroxine, [Fe(3)(C(5)H(5))(3)(C(15)H(12)B(3)O(3))], (I), and triferrocenylborazine, [Fe(3)(C(5)H(5))(3)(C(15)H(15)B(3)N(3))], (II), are isomorphous. At room temperature, the space group is Cmc2(1) and the molecules have crystallographic m symmetry. A reversible phase transition occurs at 283(2)K for (I) and at 263(5)K for (II).