Diaminations are a girl's best friend : New reactions in the field of transition‐metal‐catalyzed diamination of olefins provide a powerful tool for the elaboration of more complex molecules bearing the 1,2‐diamine moiety. An overview of these methods, including asymmetric versions, is given.
Two series of BODIPY dyes with substituents either in the α positions or in the β positions and different conjugation lengths were synthesized by means of iridium‐catalyzed borylation and rhodium‐catalyzed Heck‐type addition (see scheme). The α‐ and β‐substituted series show completely different photophysical properties. BODIPY=boron dipyrrin.
Brilliance of terbium : Heterodimeric conjugates of trimethoprim covalently linked to sensitized terbium chelates bind to Escherichia coli dihydrofolate reductase fusion proteins with nanomolar affinity (see picture). Terbium luminescence enables sensitive and time‐resolved detection of labeled proteins in vitro and on the surface of living mammalian cells.
The nucleation process of iron‐exchanged zeolite Fe‐ZSM‐5, from the assembly of distorted tetrahedrally coordinated iron species and silicate rings in the precursor to the final Fe‐ZSM‐5 crystals, as well as variations in the coordination environment of iron, were studied by UV resonance Raman spectroscopy and complementary techniques.
Wheels on water? A waterwheel‐shaped porphyrin pentamer has been synthesized by palladium‐catalyzed cross‐coupling reactions. The key intermediate is a boronate porphyrin, in which four boronic ester groups are directly attached to the meso‐positions.
Don′t tell azole : The first metal‐catalyzed direct coupling of metal sulfides with aryl halides and subsequent intramolecular condensation provided substituted benzothiazoles (see scheme). A wide range of functional groups are tolerated under the reaction conditions.
Two‐step magnetic transitions : An azide‐bridged 1D MnIII coordination polymer with a unique single end‐on mode was prepared; it displayed atypical antiferromagnetic couplings and field‐induced two‐step magnetic transitions (see figure). The spin‐canted phenomenon in the antiferromagnetic chain complex plays a pivotal role in establishing the slow magnetic relaxation.
Oil and water : A new energy‐efficient and atom‐economical catalytic route for the production of alkanes and methanol by upgrading the phenolic fraction of bio‐oil has been developed. The one‐pot aqueous‐phase hydrodeoxygenation process is based on two catalysts facilitating consecutive hydrogenation, hydrolysis, and dehydration reactions.
Changing places : Intramolecular B(pin)/H exchange took place in the presence of a platinum–phosphane catalyst, giving synthetically useful cis‐β‐methyl‐substituted alkenylboronates stereoselectively (see scheme; B(pin)=4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl).
Detection of pathogenic Escherichia coli is of the utmost importance in the food industry, water and environmental quality control, and clinical diagnosis for health and safety reasons. In their Full Paper on page 2289 ff., H. Liu et al. describe glycopolymers, with the use of poly(ethylene glycol), as glycoside‐tethered spacers that offer the sensitive detection of E. coli, as a result of the significantly reduced steric binding hindrance of the polymeric carbohydrates to the bacterial pili.
A trap that closes with a “click” : The copper‐catalyzed azide–alkyne cycloaddition can occur in different G‐quadruplex structures (see scheme). The species trapped by the click reaction can then be separated and analyzed. By using this approach, a DNA–RNA hybrid‐type G‐quadruplex structure formed by human telomeric DNA and RNA sequences was detected.
Two photons are better than one : This principle applies to a wide range of applications, ranging from engineering to physiology. Recent advances in our understanding of the phenomenon of two‐photon absorption (see picture) and in the design of two‐photon dyes are rapidly increasing the scope of this field.
Osmabenzenes can be easily synthesized from two η2‐coordinated olefin osmacycles in the presence of benzonitrile by means of facile hydrogen‐transfer conversions (see graphic). Mechanisms for the formation of osmabenzenes are proposed based on DFT calculations.
Easy and direct : Regioselective Mizoroki–Heck‐coupling reactions using heteroaromatic tosylates as electrophiles were achieved, thus providing direct and easy access to highly functionalized α‐heteroarylvinyl amides and ethers.
Tuning electronic properties and morphologies : We report a unique design platform of n‐type organic semiconductors based on asymmetrically substituted bisphenazines that enable tuning of both electronic properties and morphologies of 1D nanostructures (see figure) by using small substituents with various sizes and electronic demands.
Round and round : Covalently bound spokes induce an efficient template‐directed cyclization towards a rigid molecular wheel (see figure) and afford dramatically increased shape‐persistence properties compared with non‐strutted macrocycles.
Click to view : Glycopolymers can be used to display glycans on microarrays in native‐like architectures. The structurally uniform alkyne‐terminated mucin mimetic glycopolymers (see picture; TR=fluorophore) were printed on azide‐functionalized chips by microcontact printing in the presence of a copper catalyst. The surface‐bound glycopolymers bind lectins in a ligand‐specific manner.
