Electron by electron : β‐Diketiminato nickel(I) complex fragments are capable of activating N2 through coordination. The resulting complex can be reduced in two single‐electron steps, which further activates the N? N bond. The picture shows the structure of the singly reduced complex with μ‐η1:η1‐bound N2.
Taking shortcuts : A remarkably short and high‐yielding asymmetric total synthesis of (?)‐oseltamivir takes advantage of organocatalysis and single‐pot domino operations. The target, known as the drug Tamiflu, is prepared efficiently in a short time, and also its derivatives can be synthesized effectively.
All change : Complete ligand exchange through the hydrogenation of [Ru(η4‐cod)(η6‐cot)] in the presence of GaCp* under mild conditions leads to the title complex featuring a “naked” gallium atom bridging two ruthenium centers (see structure: C white, Ga blue, Ru red). This cluster can be considered as a trapped intermediate on the way to mixed‐metal nanoparticles; cot=1,3,5‐cyclooctatriene; cod=1,5‐cyclooctadiene, Cp*=C5Me5.
Y not? A unique, three‐coordinate Y‐shaped bis(silyl)platinum(II) complex was isolated and characterized (see structure; C light gray, N blue, Si pink, Pt dark gray). DFT studies on a model system shed light on the nature of this unusual coordination mode for platinum(II).
Perfluoroaryl boranes are an important class of organometallic Lewis acids. The synthesis of perfluorinated compounds brings special challenges to tried‐and‐true synthetic methodologies. In their Communication on page 2955 ff., W. E. Piers and co‐workers present the synthesis of a new, fully fluorinated heterocyclic borane that is also a member of the rare antiaromatic borole class of compounds. The route relies on normally facile transmetallation reactions made more difficult by the electron‐withdrawing C6F5 groups of the target product.
Perlen auf Gold : Neuartige multifunktionelle Nanopartikel bestehen aus einzelnen Amin‐modifizierten Goldnanostäbchen, an denen Fe3O4‐„Perlen“ mit Carboxyendgruppe angebracht sind. Die Partikel eignen sich zur simultanen Erkennung, dualen Bildgebung und photothermischen Ablation von Brustkrebszellen.
Nice coat! Organically modified silica (ormosil) is used for the ultrathin nanoprecise coating of individual multiwall carbon nanotubes using a soft‐chemistry approach. The coating layer has a uniform thickness of about 3 nm. The ormosil coating demonstrates the favorable electrical insulating properties of individual multiwall carbon nanotubes.
Additional cyclization : Dicyanonitrosomethanide, [C(CN)2(NO)]? undergoes nucleophilic addition and cyclization of 1,2‐diaminoethane and 1,3‐diaminopropane on the nitrile groups to form imidazolinyl and 1,4,5,6‐tetrahydropyrimidinyl groups, respectively. Ethanolamine has lower reactivity and fails to cyclize.
Polyimides were synthesized from pyromellitic dianhydride (PMDA), 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), and three different diamines with the following general structure: where R is ethyl, propyl, or isobutyl. The poly(amic acids) obtained had inherent viscosities ranging from 0.30 to 0.93 and were thermally/chemically converted to polyimides. The thermal stability of the polyimides was evaluated by using dynamic thermogravimetric analysis in air. Physical and thermal properties of these polyimides were compared with that obtained by reacting 2,2-bis(4-aminophenyl) propane and PMDA/BTDA. 相似文献
Preferred protonation : Does electrospray ionization mass spectrometry produce gas‐phase or liquid‐phase structures? The preferred protonation site in p‐aminobenzoic acid depends upon the medium, and the structure of its conjugate acid varies with the solvent used during spraying.
Inside Back Cover picture shows The carps trying hard to make a successful jump over the Dragon Gate will change into fish‐dragons, which is a legend handed down in China over generations. The back cover picture shows photochemical and electrochemical CO2 transformations with organic compounds through the utilization of solar energy or electric energy, producing a series of valuable products, including carboxylic acids and hetero‐cyclic compounds. The combined utilization of both clean energy and CO2 has attracted increasing attention in sustainable development of renewable energy and green chemistry. Recent advances are summarized by He et al. on page 644–659.
Linked to the Pentagon : The addition of molybdate to [HBW11O39]8? ions leads to the formation of mixed pentagonal units {W(Mo5)} and {W(WMo4)} trapped as linkers in the resulting modular assemblies, thus establishing the first link between the conventional Keggin ion derivatives and the giant molybdenum oxide and keplerate ions.
Ligand substitution reactions on square-planar platinum (II) complexes of the types trans-[PtRXL2], trans-[PtR(4-PADA)L2][BF4], trans-[PtRX( ) and trans-[PtR(4-PADA)( )][BF4] R=H, Me; X=Cl?, I?; L=PEt3, bis(3-trifluoromethyl-phenyl)benzylphosphine ( 4 ), =the trans-spanning 2,11-bis[bis(3-trifluoro-methylphenyl)phosphinomethyl]benzo [c]phenanthrene ( 3 ); 4-PADA (=pyridine-4-azo-4′-(N, N-dimethyl)aniline have been studied at 30° using stopped-flow and conventional spectrophotometry, methanol as solvent, and 2.5 × 10?2 M ionic strength (LiClO4 as supporting electrolyte). 4-PADA was used as indicator ligand, as its absorption spectrum differs from those spectra where it is complexed. The expected steric effects of the bulky ligands, especially of 3 , on the rates and mechanisms of all the reactions studied are small. All reactions take place by the usual two-term rate law. Noteworthy, for the complexes with the bulky ligands 3 and 4 , the direct reaction path with the entering nucleophile is predominant. There is no preference for a solvent or dissociative path. The reactivity order for the hydride complexes is trans-[PtHX (PEt3)2]<trans-[PtHX( 4 )2]<trans-[PtHX ( 3 )]. However, for the corresponding methyl complexes, there is some retardation by ligand 3 , probably due to an interaction between the methyl group and the hydrocarbon moiety of 3 , which inhibits the fluxional behavior of this ligand. The results have some relevance for the understanding of olefin-insertion reactions of hydride complexes containing these phosphine ligands. 相似文献
A spin‐crossover cluster with the {FeII4O4} core structure is presented by D. Y. Wu, O. Sato et al. in their Communication on page 1475 ff. The cluster is synthesized by self‐assembly and shows an abrupt spin transition, giving two high‐spin and two low‐spin states. It exhibits complete light‐induced excited spin‐state trapping effects. Importantly, synergy effects between the magnetic interaction and spin transition operate in the cluster.
Bidirectional chemo‐switching of magnetism occurs in a microporous coordination polymer containing spin‐crossover subunits, as described by M. Ohba, J. A. Real, S. Kitagawa, and co‐workers in their Communication on page 4767 ff. In situ magnetic measurements reveal that most guest molecules transform the framework spin state from diamagnetic low spin (red) to paramagnetic high spin (yellow), whereas the guest CS2 stabilizes the low‐spin state. These induced spin states are retained as a memory effect after the release of the guest.
Ordered water : Gypsum has been used for construction for millennia. The structure and water content of calcined gypsum, CaSO4?0.5 H2O, has been under discussion until now: single‐crystal structure analysis (see picture: S yellow, Ca gray, O blue, H red) provides an ordered model that is confirmed by DFT calculations.
