Expanded porphyrins : The electronic excited states of two forms of meso‐hexakis(pentafluorophenyl)‐substituted gold(III) hexaphyrin(1.1.1.1.1.1), such as that depicted, have been investigated by density functional calculations and magnetic circular dichroism spectroscopy to assign their low‐energy excited singlet states.
The appropriate choice of chiral catalyst and starting materials leads to the synthesis of 1,2‐oxazetidin‐3‐ones by cycloadditions of ketenes with nitroso compounds with very good regioselectivity and enantioselectivity. In addition to serving as potentially bioactive target molecules, the products can be transformed into other important classes of compounds, such as α‐hydroxycarboxylic acid derivatives.
Lighting one by one: The electroluminescence (EL) from single molecules of a red phosphorescent iridium complex dispersed in a hole‐transporting polymer matrix is studied. The single‐molecule EL dynamics is determined by local structural inhomogeneities in the matrix polymer (see picture).
Leading light : A series of zinc(II) bis‐terpyridine complexes (see picture) is investigated by means of DFT calculations combined with Bader's quantum theory of atoms in molecules. Raman spectroscopy experiments and studies of the electro‐optical properties of the complexes in solution and the solid state are also performed to examine their potential as new emissive materials in light‐emitting devices.
Gone fishing : When propiophenone and related ethyl ketones are treated with morpholine in the presence of K3PO4, chlorobenzene, and [Ni(cod)2]/PMe3 catalyst, a carbon–nitrogen bond is formed selectively at the β position (see scheme; cod=cycloocta‐1,5‐diene). Secondary amines were employed as substrates to give the corresponding β‐enaminones.
Flexible friends : A new strategy that relies on o‐DPPB‐directed allylic substitution has been implemented for the flexible and stereospecific construction of major polyketide and isoprenoid structural elements (see scheme; o‐DPPB=ortho‐diphenylphosphanyl benzoate; PG=protecting group).
Trapped! Mesopolymer‐entrapped Pt nanoparticles serve as an efficient catalyst for the hydrogenation of benzaldehydes in water at ambient temperature. In comparison with the commercial Pt/alumina catalyst, the Pt/FDU‐14 catalyst shows superior performance in the hydrogenation reaction. The catalyst afforded high turnover frequencies and was reusable more than nine times without loss of activity or selectivity.
Into my arms : Photochemical cyclization of diarylethenes that have two chiral side arms showed up to 100 % de (see scheme). Introduction of these chiral side arms onto the carbon atoms where ring closure occurs is a general strategy for the highly diastereoselective cyclization of diarylethenes.
A would‐be amide : A 1,4‐disubstituted 1,2,3‐triazole was used as a surrogate for a trans amide bond to create a library of 16 diastereomeric pseudotetrapeptides as β‐turn mimetics. High‐resolution structural analysis indicated that these scaffolds adopt distinct, rigid, conformationally homogeneous β‐turn‐like structures (see example), some of which bind somatostatin receptor subtypes selectively, and some of which show broad‐spectrum activity.
An‐T‐biotic : The first total synthesis of the T‐shaped bisanthraquinone natural product BE‐43472B was accomplished and its absolute configuration assigned. Key transformations in the pivotal cascade sequence include a Diels–Alder reaction, a hemiketal formation, and a nucleophilic aromatic ipso substitution.
Broken switch : Guest‐accessible metal sites are generated on the pore surface of a porous coordination polymer (see figure) through the complementary coordination‐bond rearrangement in a single‐crystal‐to‐single‐crystal fashion, which is triggered by the removal of coordinated water.
Just add it! Ruthenium initiators functionalized with hydrogen‐bonding sites were utilized in ring‐opening metathesis polymerization to prepare heterotelechelic polymers with hydrogen‐bonding and metal‐coordination units in a single step. Supramolecular ABC triblock copolymers were then self‐assembled in one pot by simply adding complementary telechelic polymers to a solution of the heterotelechelic polymer (see picture).
Insight into bonding phenomena depends on whether one analyzes the whole bond‐formation process or just the final product. Examination of the formation of the inclusion complex He@adamantane by energy partitioning reveals that the high energy cost of “He bonding” originates in strong He? C Pauli repulsions. The postulate of attractive He? C bonds requires a very specific view.
Down to the wire : A simple and effective method to synthesize silver nanowires through an ionic‐liquid‐assisted polyol process is developed (see scheme; scale bar=5 nm). The ionic liquids are tuned to provide the anisotropic growth of silver nanoparticles into nanowires.
