Synthesis and characterization of soluble conjugated polymers having pyrene moiety in the main chain

Poly[(arylene ethynylene)-alt-(arylene vinylene)]s Based on Anthanthrone and Its Derivatives: Synthesis and Photophysical, Electrochemical, Electroluminescent, and Photovoltaic Properties

Anthanthrone and its derivatives are large polycyclic aromatic compounds (PACs) that pose a number of challenges for incorporation into the structure of soluble conjugated polymers. For the first time, this group of PACs was employed as the building blocks for the synthesis of copolymers (P1-P5) based on poly[(arylene ethynylene)-alt-(arylene vinylene)]s backbone (-Ph-C≡C-Anth-C≡C-Ph-CH=CH-Ph-CH=CH-) _n . During the synthesis of P1-P5, different alkyloxy side chains were incorporated in order to tune the properties of the polymers. Of the copolymer series only P1 (containing anthanthrone and branched 2-ethylhexyloxy side chains on phenylenes), P2 and P3 (for which the anthanthrones containing carbonyl groups were converted to anthanthrene containing alkyloxy substituents) were soluble. The photophysical, electrochemical, electroluminescent and photovoltaic properties of P1-P3 are reported, compared and discussed with respect to the effects of side chains.

Pyrene Molecular Orbital Shuffle-Controlling Excited State and Redox Properties by Changing the Nature of the Frontier Orbitals

We show that by judicious choice of substituents at the 2- and 7-positions of pyrene, the frontier orbital order of pyrene can be modified, giving enhanced control over the nature and properties of the photoexcited states and the redox potentials. Specifically, we introduced a julolidine-like moiety and Bmes₂ (mes=2,4,6-Me₃ C₆ H₂ ) as very strong donor (D) and acceptor (A), respectively, giving 2,7-D-π-D- and unsymmetric 2,7-D-π-A-pyrene derivatives, in which the donor destabilizes the HOMO-1 and the acceptor stabilizes the LUMO+1 of the pyrene core. Consequently, for 2,7-substituted pyrene derivatives, unusual properties are obtained. For example, very large bathochromic shifts were observed for all of our compounds, and unprecedented green light emission occurs for the D/D system. In addition, very high radiative rate constants in solution and in the solid state were recorded for the D-π-D- and D-π-A-substituted compounds. All compounds show reversible one-electron oxidations, and Jul₂ Pyr exhibits a second oxidation, with the largest potential splitting (ΔE=440 mV) thus far reported for 2,7-substituted pyrenes. Spectroelectrochemical measurements confirm an unexpectedly strong coupling between the 2,7-substituents in our pyrene derivatives.

Physicochemical and Luminescent Properties of Copolymers Composed of Three Monomers: Polythiophenes Based on 3-Hexylthiophene and 3,4-Ethylenedioxythiophene

The chemical synthesis and physicochemical and luminescent characterizations of polymers based on 3-HT, EDOT, and 2,2′-(9,9-dioctyl-9H-fluorene-2,7-diyl) bisthiophene (fluorene) or (E)-2-(ethyl(4-((4-nitrophenyl)diazenyl)phenyl)amino)ethyl 2-(thiophen-3-yl)acetate (TDR1) are reported. The fluorene unit was bound to the conjugate backbone, while the Disperse Red 1 (DR1) chromophore was present as a pendant group. Characterizations by 1H NMR, FT-IR, DSC-TGA, GPC, UV-vis, cyclic voltammetry, fluorescence quantum yield, excited state lifetime, and two-photon absorption cross-section were carried out. These polymers combined the physicochemical properties of EDOT and 3-HT, such as high electron density, high charge mobility, low oxidation potential, and good processability. The optical properties of these copolymers were highly dependent on the presence of EDOT, the molecular weight, and the regioregularity rather than the presence of the third component (fluorene or TDR1). The good nonlinear absorption and luminescent properties exhibited by these copolymers were exploited to fabricate nanoparticles used as fluorescent tags for the imaging of microstructures.

Tubes or sheets: divergent aggregation pathways of an amphiphilic 2,7-substituted pyrene trimer

The self-assembly of an amphiphilic 2,7-linked pyrene trimer in an aqueous environment into two morphologically related forms is described. Supramolecular polymerization leads to the simultaneous formation of nanosheets and nanotubes.

Recent developments in the Suzuki-Miyaura reaction: 2010-2014

The Suzuki-Miyaura reaction (SMR), involving the coupling of an organoboron reagent and an organic halide or pseudo-halide in the presence of a palladium or nickel catalyst and a base, has arguably become one of most utilized tools for the construction of a C-C bond. This review intends to be general account of all types of catalytic systems, new coupling partners and applications, including the literature between September 2010 and December 2014.

Anthanthrene as a large PAH building block for the synthesis of conjugated polymers

New anthanthrene-based conjugated polymers exhibiting promising optical and electronic properties for organic electronics applications were prepared from low-cost vat orange 3.

Pd(OAc)2/o-chloranil/M(OTf)n: a catalyst for the direct C-H arylation of polycyclic aromatic hydrocarbons with boryl-, silyl-, and unfunctionalized arenes

Pd(OAc)(2)/o-chloranil/M(OTf)(n) can effectively promote the C-H arylation of fluoranthene with arylboron compounds or arylsilanes. The reaction takes place with high regioselectivity at the C3 position of fluoranthene. Moreover, the new catalytic system allows the use of unfunctionalized arenes as coupling partners in the arylation of polycyclic aromatic hydrocarbons.