A mild access to silver acetylides from trimethylsilyl acetylenes

1-Trimethylsilyl-1-alkynes are selectively converted to the corresponding silver acetylides. Silver nitrate or triflate are used under neutral conditions, allowing other functional groups to remain unaffected.     

The chemistry of organic nanomaterials

The development of nanotechnology using organic materials is one of the most intellectually and commercially exciting stories of our times. Advances in synthetic chemistry and in methods for the investigation and manipulation of individual molecules and small ensembles of molecules have produced major advances in the field of organic nanomaterials. The new insights into the optical and electronic properties of molecules obtained by means of single-molecule spectroscopy and scanning probe microscopy have spurred chemists to conceive and make novel molecular and supramolecular designs. Methods have also been sought to exploit the properties of these materials in optoelectronic devices, and prototypes and models for new nanoscale devices have been demonstrated. This Review aims to show how the interaction between synthetic chemistry and spectroscopy has driven the field of organic nanomaterials forward towards the ultimate goal of new technology.     

"One-step" alkynylation of adamantyl iodide with silver(I) acetylides

[reaction: see text] Silver(I) acetylides allow one-step alkynylation of adamantyl iodide in yields ranging from 25 to 68%.     

Coordination chemistry of silver cations

While in pure solvents Ag(+) is known to be tetrahedrally coordinated, in the presence of ligands such as ammonia it forms linear complexes, usually explained by the ion's tendency toward sd-hybridization. To explore this disparity, we have investigated the reaction of ammoniated silver cations Ag(+)(NH(3))(n)(), n = 11-23, with H(2)O as well as the complementary process, the reaction of Ag(+)(H(2)O)(n)(), n = 25-45, with NH(3) by means of FT-ICR mass spectrometry. In both cases, ligand exchange reactions take place, leading to clusters with a limited number of NH(3) ligands. The former reaction proceeds very rapidly until only three NH(3) ligands are left, followed by a much slower loss of an additional ligand to form Ag(+)(NH(3))(2)(H(2)O)(m)() clusters. In the complementary process, the reaction of Ag(+)(H(2)O)(n)() with NH(3) five ammonia ligands are very rapidly taken up by the clusters, with a much less efficient uptake of a sixth one. The accompanying DFT calculations reveal a delicate balance between competing effects where not only the preference of Ag(+) for sd-hybridization, but also its ability to polarize the ligands and thus affect the strength of their hydrogen bonding, as well as the ability of the solvent to form extended hydrogen-bonded networks are important.     

The organic chemistry of deoxynucleosides and deoxynucleotides

The organic chemistry of the naturally occurring deoxynucleosides and their phosphate esters is reviewed.     

The nucleophilicity N index in organic chemistry

The nucleophilicity N index (J. Org. Chem. 2008, 73, 4615), the inverse of the electrophilicity, 1/ω, and the recently proposed inverse of the electrodonating power, 1/ω?, (J. Org. Chem. 2010, 75, 4957) have been checked toward (i) a series of single 5-substituted indoles for which rate constants are available, (ii) a series of para-substituted phenols, and for (iii) a series of 2,5-disubstituted bicyclic[2.2.1]hepta-2,5-dienes which display concurrently electrophilic and nucleophilic behaviors. While all considered indices account well for the nucleophilic behavior of organic molecules having a single substitution, the nucleophilicity N index works better for more complex molecules. Unlike, the inverse of the electrophilicity, 1/ω, (R(2) = 0.71), and the inverse of the electrodonating power, 1/ω? (R(2) = 0.83), a very good correlation of the nucleophilicity N index of twelve 2-substituted-6-methoxy-bicyclic[2.2.1]hepta-2,5-dienes versus the activation energy associated with the nucleophilic attack on 1,1-dicyanoethylene is found (R(2) = 0.99). This comparative study allows to assert that the nucleophilicity N index is a measure of the nucleophilicity of complex organic molecules displaying concurrently electrophilic and nucleophilic behaviors.     

The structural theory and physical organic chemistry

Woolley's revolutionary proposal that quantum mechanics does not sanction the concept of “molecular structure”—which is but only a “metaphor”—has fundamental implications for physical organic chemistry. On the one hand, the Uncertainty Principle limits the precision with which transition state structures may be defined; on the other, extension of the structure concept to the transition state may be unviable. Attempts to define transition states have indeed caused controversy. Consequences for molecular recognition, and a mechanistic classification, are also discussed.     

有机微波化学研究进展

本文综述了近几年来微波技术在有机合成方面的研究和应用进展。初步探讨了微波催化有机反应的作用机理, 并展望了有机微波化学的发展前景。     

The role of mass spectrometry in organic chemistry

It is well known that mass spectrometry (MS) is a very versatile physical method which is applied to many branches of chemistry. Two main lines of development can be discerned: (i) organic chemical analysis. (ii) gas phase chemistry of organic ions. Both will be surveyed and discussed and will be followed by some speculations on future developments.     

The chemistry and biology of organic guanidine derivatives

Organic guanidine compounds are reviewed, with emphasis on natural products isolation, identification, synthesis and biological activities. The literature survey includes purely synthetic guanidine derivatives, guanidine alkaloids and non-ribosomal peptides from bacteria and cyanobacteria, as well as related compounds isolated from marine and terrestrial invertebrates and higher plants.     

Perfluoro organic compounds of silver

Non fluorinated organo silver compounds are thermally unstable. In contrast fluorinated organo silver compounds are thermally more stable, the stability increasing with perfluoro aromatic counterparts rather than perfluoro aliphatic systems.The synthesis of pentafluorophenyl silver can be done by several methods:

Similar results are obtained using complexes of silver pentafluorobenzoate with α, α′-Dipyridyl or o-phenanthroline as starting compounds.The C₆F-Ag-compounds react as C₆F₅-transferring systems. Their structur seems to consist of clusters, the highest mass number found corresponding to [Ag₄(C₆F₅)₃]⁺. On thermal degradation [Ag₂C₆F₅]_n seems to be formed.Increased thermal stability is shown by Paratetrafluorophenylene disilver, which is formed by decarboxylation of silver tetrafluoro terephthalate. Although insoluble in organic solvents it can be reacted in suspension yielding 1,4 derivatives of tetrafluorobenzene. All complexes of silver tetrafluoro phthalate are degraded during decarboxylation with the formation of Para-tetrafluorophenylene disilver.