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Coordination of ambiphilic diphosphine-silane ligands [o-(iPr2P)C6H4]2Si(R)F (R=F, Ph, Me) to AuCl affords pentacoordinate neutral silicon compounds in which the metal atom acts as a Lewis base. X-ray diffraction analyses, NMR spectroscopy, and DFT calculations substantiate the presence of Au[rarr]Si interactions in these complexes, which result in trigonal-bipyramidal geometries around silicon. The presence of a single electron-withdrawing fluorine atom is sufficient to observe coordination of the silane as a [sigma]-acceptor ligand, provided it is positioned trans to gold. The nature of the second substituent at silicon (R=F, Ph, Me) has very little influence on the magnitude of the Au[rarr]Si interaction, in marked contrast to N[rarr]Si adducts. According to variable-temperature and 2D EXSY NMR experiments, the apical/equatorial positions around silicon exchange in the slow regime of the NMR timescale. The two forms, with the fluorine atom in trans or cis position to gold, were characterized spectroscopically and the activation barrier for their interconversion was estimated. The bonding and relative stability of the two isomeric structures were assessed by DFT calculations.

Transition-metal-activated alkynes or allenes can accept nucleophilic attack and undergo direct addition of the nucleophiles to the unsaturated bonds or trigger subsequent rearrangement reactions. This chemistry has witnessed increasing development in recent years. In this report, we have focused on the metal-catalyzed reactions of a variety of substituted propargyl allenic alcohols and thiophenols using indium(III) and zinc(II) catalysts, which can activate both the alcohol and alkyne. In this reaction, thio groups play the role of a nucleophile and trigger subsequent rearrangements to give benzene derivatives. The products can be further transformed into various 1,3,5-trisubstituted aromatic compounds by nickel-catalyzed coupling reactions through the cleavage of the C[bond]S bonds.

Applying a palladium/dppf catalyst system, the synthesis of primary amides from aryl halides and ammonia is possible under mild reaction conditions in moderate to excellent yields.

Better together: A novel hybrid N-heterocyclic carbene (NHC) palladium complex, integrating a totally inorganic and polyanionic decatungstate unit, has been synthesized following a convergent strategy. The interplay of the Pd binding domains with the inorganic scaffold is instrumental in accessing multi-turnover catalysis in C[bond]C cross-coupling and aromatic dehalogenation reactions under MW-assisted protocols (see scheme).

What are you? Deprotonation of fluorenylidene phosphonium salts generates reactive intermediates that can be described as push-pull cumulenes or singlet carbenes (see scheme). Whereas the NMR data are ambiguous, the coordination behavior shows the ready availability of a lone pair at the central C atom. The donor ability of singlet carbene ligands of this new class exceeds that of the commonly used N-heterocyclic carbenes (NHCs).

The definite interest in implementing sustainable industrial technologies has impelled the use of biocatalysts (enzymes or cells), leading to high chemo-, regio- and stereoselectivities under mild conditions. As usual substrates are not soluble in water, the employ of organic solvents is mandatory. We will focus on different attempts to combine the valuable properties of green solvents with the advantages of using biocatalysts for developing cleaner synthetic processes.

There[prime]s just NO SNAP! RuIII complexes of macrocyclic tertiary amines, especially trans-[Ru(14-TMC)Cl2]Cl (1), could mediate nitric oxide (NO) release from S-nitrosothiols in the presence of biological reductants. Interestingly, complex 1 was found to enhance rat aorta relaxation in the presence of S-nitroso-N-acetylpenicillamine (SNAP) under in vivo conditions.

As a unique technique at the singe-molecule level to explore the distribution and temporal order of events, nanopore technology has attracted increasing attention. In comparison to the previous applications in DNA sequencing, this Focus Review highlights the technical details of biological nanopores, especially [alpha]-hemolysin, in the analysis of peptides and proteins. The instrument configurations, experimental interferences, and data analysis including the conformation of peptides and proteins and their interactions for single-molecule detection are discussed.

Two Janus [2]rotaxanes, 5 a and 5 b, with [alpha]-cyclodextrin ([alpha]-CD) derivatives substituted on the 6-position with two recognition sites (azobenzene and heptamethylene (C7)) that were linked with linkers of different lengths (oligo(ethylene glycol) with a degree of polymerization equal to 2 or approximately 21) were synthesized and characterized. 2D ROESY NMR spectroscopy and circular dichroism (cd) spectra demonstrated that the recognition site of the [alpha]-CD moiety was switched by photoisomerization of the azobenzene moiety in 5 a and 5 b. The different size changes of 5 a and 5 b in hydrodynamic radius (RH) owing to the different length of linker between two recognition sites were observed by pulse-field-gradient spin-echo NMR spectroscopy. The kinetic results indicated that the different length of linker had no or a weak effect for the photoisomerization process of 5 a and 5 b.

A novel series of ladder [pi]-conjugated materials - sila-pentathienoacenes (Si-PTA) are synthesized and characterized. Crystal structures of the compounds show that the length of alkyl chains substituting on the thiophene ring has a significant influence on molecular packing. A densely packed structure with an interfacial distance of about 3.66 Å between the adjacent molecules is observed for the compound with shorter alkyl chains. However, a large interfacial distance (7.99 Å) is obtained for another compound because of the insertion of long alkyl chains between two planes. The investigation of the optical and electrochemical properties shows that the silylene bridge incorporated into the pentathienoacene framework exerts a clear effect on the electronic properties by the [sigma]*-[pi]* conjugation. Although only a slight enhancement is observed for the HOMO levels, with respect to that of pentathienoacene, the LUMO levels are significantly lowered. The observed electronic properties are consistent with the theoretical calculations.