Synthesis of Substituted Tricyclo[5.3.1.04,9]undecan‐2,6‐dione from 4,4‐Disubstituted Cyclohexanone Enamines and Methacryloyl Chloride

Morpholine enamines 4‐acetyl‐4‐methyl‐1‐morpholinocyclohexene 4a, 4‐acetyl‐4‐phenyl‐1‐morpholinocyclohexene 4b, and 4‐acetyl‐4‐isopropenyl‐1‐morpholinocyclohexene 4c react with methacryloyl chloride to give 1,7‐dimethyl‐4(N‐morpholino) tricyclo[5.3.1.0^4,9]undecan‐2,6‐dione 9a , 1‐phenyl‐7‐methyl‐4(N‐morpholino) tricyclo[5.3.1.0^4,9]undecan‐2,6‐dione 9b , and 1‐ispropenyl‐7‐methyl‐4(N‐morpholino) tricyclo[5.3.1.0^4,9]undecan‐2,6‐dione 9c respectively, along with the corresponding substituted adamandane‐2,4‐diones.     

Synthesis and Characterization of Liquid-Crystalline Tetraoxapentacene Derivatives Exhibiting Aggregation-Induced Emission

A series of new tetrakis(dialkoxyphenyl) dicyanotetraoxapentacene derivatives ( 1 a – c ) were prepared by reaction of the appropriate terphenyl diols with tetrafluoroterephthalonitrile in good yields. Compounds 1 b and 1 c , which bear hexyloxy and decyloxy side chains, exhibited columnar hexagonal mesophases, as shown by polarized optical microscopy, variable-temperature powder X-ray diffraction, and differential scanning calorimetry. Single-crystal X-ray diffraction of methoxy-substituted 1 a revealed that the dicyanotetraoxapentacene core is highly planar, consistent with the notion that these molecules are able to stack in columnar mesophases. A detailed photophysical characterization showed that these compounds exhibit aggregation-induced emission in solution, emission in nonpolar solvents, weak emission in polar solvents, and strong emission in the solid state both as powder and in thin films. These observations are consistent with a weakly emissive charge-transfer state in polar solvents and a more highly emissive locally excited state in nonpolar solvents.     

Fluid phase equilibria of binary and ternary mixtures of supercritical carbon dioxide with tetradecanoic acid and docosane up to 43 MPa and 393 K: cosolvency effect and miscibility windows

Isothermal pressure (p)-mass fraction (w) phase diagrams were measured for CO₂ + tetradecanoic acid at six temperatures from 328.2 K to 373.2 K and for CO₂ + docosane at four temperatures from 343.2 K to 393.2 K as well as isobaric temperature (T)-mass fraction (w) phase diagrams for both systems at 34.5 MPa. In addition the isothermal and isobaric Gibbs phase prisms at 373.2 K and 34.5 MPa respectively were determined for the ternary system CO₂ + tetradecanoic acid + docosane, and and isobaric miscibility window was found between 333 K and 385 K at 34.5 MPa.     

Base‐Stabilized Boryl and Cationic Haloborylene Complexes of Iron

The synthesis of base‐stabilized boryl and borylene complexes is reported. An N‐heterocyclic carbene (NHC)‐stabilized iron–dihydroboryl complex was prepared by two different routes including methane liberation and salt elimination. A range of base‐stabilized iron–dichloroboryl complexes was prepared by addition of Lewis bases to boryl complexes. Base‐stabilized, cationic monochloroborylene complexes were synthesized from these boryl complexes by halide abstraction by using weakly coordinating anions.     

Comparison of Oxidative Aromatic Coupling and the Scholl Reaction

Does the dehydrogenative coupling of aromatic compounds mediated by AlCl₃ at high temperatures and also by FeCl₃, MoCl₅, PIFA, or K₃[Fe(CN)₆] at room temperature proceed by the same mechanism in all cases? With the growing importance of the synthesis of aromatic compounds by double C? H activation to give various biaryl structures, this question becomes pressing. Since some of these reactions proceed only in the presence of non‐oxidizing Lewis acids and some only in the presence of certain oxidants, the authors venture the hypothesis that, depending on the electronic structure of the substrates and the nature of the “catalyst”, two different mechanisms can operate. One involves the intermediacy of a radical cation and the other the formation of a sigma complex between the acid and the substrate. The goal of this Review is to encourage further mechanistic studies hopefully leading to an in‐depth understanding of this phenomenon.