Micellar Polyaromatic Capsules: Enhanced Emissive Properties through Shell-Functionalization
Functionalization of the polyaromatic shell of a micelle-like molecular capsule was accomplished by simple functionalization of the amphiphilic subunits composed of a bent bis-anthracene framework and two trimethylammonium groups. In aqueous solutions, functionalized subunits assemble spontaneously and quantitatively into spherical capsules providing anthracene shells with external diameters of 2-3 nm through hydrophobic and aromatic-aromatic interactions. The shape and size of the functionalized capsules remain similar to the original, but the emissive intensities increase significantly (up to 5-fold) by attaching cyano or phenylethynyl groups. Furthermore, the shell-functionalization drastically enhances the host-guest photophysical properties (up to 8-fold) in the cavities of the capsules, as estimated by emission intensities from the encapsulated fluorescent dyes. Functionalization of the polyaromatic shell of a micelle-like molecular capsule was accomplished by simple functionalization of the amphiphilic subunits. The shell-functionalization drastically enhances the host and host-guest emissive properties.
Reported herein is a palladium-catalyzed secondary benzylic imidoylative Negishi reaction leveraging the sterically bulky aromatic isocyanides as the imine source. This method allows the facile access of alkyl-, (hetero)aryl-, and alkynylzinc reagents to afford various α-substituted phenylacetone products under mild acidic hydrolysis, which are ubiquitous motifs in many pharmaceuticals and biologically active compounds. The diastereoselective reduction of imine can be accomplished to provide the expedient conversion of secondary benzylic halide into α-substituted phenethylamine derivatives with high atom economy.
Et2Zn-mediated stoichiometric C(sp)-H silylation of 1-alkynes and chlorosilanes
A first example of an Et2Zn mediated silylation of 1-aklynes is reported. A series of functional groups are tolerated in this reaction. Mechanistic studies support Zn alkynilides as intermediates in the reaction. This reaction protocol provides a practical method for the preparation of alkynylsilanes and expands the application of organometallic zinc in organic synthesis.
Huang, Pan,Xu, Dawen,Reich, Robert M.,Kaiser, Felix,Liu, Boping,Kühn, Fritz E.
supporting information
p. 1574 - 1577
(2019/05/17)
Ligand-Free Copper-Catalyzed Negishi Coupling of Alkyl-, Aryl-, and Alkynylzinc Reagents with Heteroaryl Iodides
Reported herein is an unprecedented ligand-free copper-catalyzed cross-coupling of alkyl-, aryl-, and alkynylzinc reagents with heteroaryl iodides. The reaction proceeds at room temperature for the coupling of primary, secondary, and tertiary alkylzinc reagents with heteroaryl iodides without rearrangement. An elevated temperature (100 C) is required for aryl-heteroaryl and alkynyl-heteroaryl couplings.
PROCESSES FOR PRODUCING POLY-ETHYNYL-SUBSTITUTED AROMATIC COMPOUND
A process for preparing a poly-ethynyl-substituted aromatic compound characterized by reacting a halogenated benzene with an ethynylzinc halide; a process for preparing a poly-ethynyl-substituted aromatic compound characterized by using a halogenated benzene having at least two kinds of halogen atoms as a halogenated benzene, and (A) reacting one kind of the halogen atoms existing in the halogenated benzene with an ethynyl group-containing compound; and (B) reacting the other kind of halogen atoms remaining in the formed compound with an ethynylzinc halide. The poly-ethynyl-substituted aromatic compound is used as liquid crystals, nonlinear optical materials, electroconductive materials and the like
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(2010/02/05)
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