A Zn(2+)-specific molecular probe 3 was developed for the selective detection of CN(-) under aqueous conditions. The fluorescent Zn(2+) complex of 3 upon CN(-) addition generates a bright blue fluorescence that allows the detection of the latter and is useful for the screening of natural products with and without endogenous cyanide content.

The formation of discrete macrocycles wrapped around single-walled carbon nanotubes (SWCNTs) has recently emerged as an appealing strategy to functionalize these carbon nanomaterials and modify their properties.H ere,w e demonstrate that the reversible disulfide exchange reaction, which proceeds under mild conditions,c an install relatively large amounts of mechanically interlocked disulfide macrocycles on the one-dimensional nanotubes.S ize-selective functionalization of am ixture of SWCNTs of different diameters were observed, presumably arising from error correction and the presence of relatively rigid, curved p-systems in the key building blocks.Acombination of UV/Vis/NIR, Raman, photoluminescence excitation, and transient absorption spectroscopyindicated that the small (6,4)-SWCNTs were predominantly functionalizedbythe small macrocycles 1 2 ,whereas the larger (6,5)-SWCNTs were an ideal matchf or the larger macrocycles 2 2 .T his sizes electivity,w hich was rationalized computationally,c ould prove useful for the purification of nanotube mixtures,s ince the disulfide macrocycles can be removed quantitatively under mild reductive conditions.

Different methods for transforming N-heteroarenes into more reactive derivatives for catalytic asymmetric hydrogenation are highlighted. The first strategy consists of facilitating hydrogenation by the formation of positively charged derivatives of the heteroarene. Catalyst deactivation processes arising upon binding of the substrate to the metal center can thus be prevented and, additionally, hydrogenation of positively charged heteroarenes may also be more favored than that of their neutral analogues. The second strategy is based onScheme 4. Chelation assistance during asymmetric hydrogenation of six-membered heteroarenes.(eight examples), although in some cases small quantities of partially hydrogenated compounds were detected. Enantioselectivities were generally high (up to 90 %).www.eurjoc.org

Iridium(I) complexes of phosphine-phosphite ligands efficiently catalyze the enantioselective hydrogenation of diverse seven-membered CN-containing heterocyclic compounds (eleven examples; up to 97% ee). POP ligand L3, which incorporates an ortho-diphenyl substituted octahydrobinol phosphite fragment, provided the highest enantioselectivities in the hydrogenation of most of the heterocyclic compounds studied. The observed sense of stereoselection was rationalized by means of DFT calculations.

Various oxa-containing heterocycles (i.e. enantiopure epoxide-and oxetane-based substrates) were subjected to ring-opening with phosphorus nucleophiles. The ring-opening reactions proceeded smoothly and the resulting 1,2-, and 1,3-phosphino alcohols were efficiently isolated as stable borane complexes. These derivatives arise from regio-and stereocontrolled syntheses based on ring-opening processes of oxa-containing heterocycles. The regio-and stereochemistry of the resulting chiral products were unequivocally confirmed in many cases via single-crystal X-ray diffraction analysis.