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Starting from the commercially available 4-bromoindole, a concise and efficient enantioselective formal synthesis of (+)-cycloclavine (1) in 13 steps with 2.0% overall yield and a total synthesis of (+)-5-epi-cycloclavine (2) in 14 steps with 3.3% overall yield were achieved. Key features of the syntheses include the addition of a Grignard reagent to the C═N/Heck reaction sequence to construct the fused 6–5–6 ring systems, cyclopropanation, an ester aminolysis reaction, and the first example of the construction of a 3-azabicyclo[3,1,0]hexane through an intramolecular [3 + 2] cycloaddition/nitrogen extrusion.

Two piezochromic molecules, (2Z,4E)-2-(4-(Diphenylamino)phenyl)-5-phenylpenta-2,4-dienenitrile (1a) and (2Z,4E)-2-(4-(acridin-10(9H)-yl)phenyl)-5-phenylpenta-2,4-dienenitrile (1b), were synthesized by using Knoevenagel and Buchwald-Hartwig cross-coupling reactions. Their piezochromic fluorescence behavior was tuned by subtle structural change. The system indicates typical intramolecular charge-transfer properties. The luminescence intensity of 1a decreased with increasing pressure with the redshift of the emission wavelength when the hydrostatic pressure in a diamond anvil cell (DAC) was applied on its crystal. However, the emission wavelength of 1b which has a methylene unit more than 1a had no obvious shift and the intensity increased gradually at the pressure range from 0.66 GPa to 5.72 GPa.

The synthesis of the enantiomerically pure

A new chiral tribenzotriquinacene bearing an ortho-bromoaniline nucleus was synthesized and optically resolved. The individual enantiomers, the absolute configuration of which was confirmed by single-crystal X-ray structure analysis, were stereoselectively converted into the same pyrazine-fused syn-bis-TBTQ derivative by chirality-assisted Buchwald-Hartwig amination. The corresponding diastereomeric anti-dimer was obtained alongside the syn-dimer from the racemic sample under similar reaction conditions. X-ray structure analysis of the dimers confirmed the mutual biconcave and convex-concave configuration of their TBTQ moieties and the preservation of the orthogonal orientation of the indane wings within each of them.

An unprecedented visible-light photoredox-catalyzed iminyl radical formation by N–H cleavage with H2 release has been developed. Its application in the synthesis of various isoquinolines and related polyaromatics in high atom economy at ambient temperature by applying a photosensitizer, Acr+-Mes ClO4–, and a new cobalt catalyst, Co(dmgH)2(4-CONMe2Py)Cl is reported. Mechanistic investigations indicated that the generated iminyl radical initiates the cascade C–N/C–C bonds formation and the catalytic cycle occurs by a simultaneous oxidative as well as reductive quenching pathway.

A rapid construction of the tetracyclic core (±)-2 of (±)-cycloclavine (1) was accomplished in seven steps and 24% overall yield from commercially available aldehyde 7. Key features include a domino Friedel-Crafts/nitro-Michael reaction to construct the C ring and an intramolecular ammonolysis of a diester to close the D ring. In addition, a versatile 4-amino Uhle's ketone (±)-3 was afforded rapidly in five steps and 43% overall yield.

An efficient and direct route to ergot alkaloid (-)-chanoclavine I (3) is described using the inexpensive compound (2R)-(+)-phenyloxirane (15) as a chiral pool in 13 steps with 17% overall yield. Key features of the synthesis include a palladium-catalyzed intramolecular aminoalkynylation of terminal olefin and a rhodium-catalyzed intramolecular [3 + 2] annulation. An oxygen-substituted ergoline derivative (-)-25 was also achieved by using the same strategy.

An enantioselective tandem Michael addition/ cyclization reaction between trisubstituted 2-nitro-1,3-enynes and cyclic 1,3-diketones catalyzed by a chiral organosquaramide catalyst in the presence of Ag2CO3 was developed. The chiral functionalized chromene products could be obtained in good yield and in 80-99% enantiomeric excess. The structures and absolute configurations of some of the products were confirmed by X-ray crystallographic analysis.

Starting from a hitherto unknown 2-aminotribenzo-triquinacene, several 2-amino-3-X-substituted TBTQ derivatives, all bearing a single ortho-difunctionalized indane wing, were synthesized as rigid and chiral building blocks for the potential construction of complex supramolecular architectures. Efficient access to two pairs of enantiomeric TBTQ derivatives, namely, the peripheral ortho-nitroaniline (X = NO2) and the related anthranilic acid (X = CO2H), was developed using chiral auxiliaries as the resolving reagents. The structure of the intermediate diastereomers was confirmed by H-1 and C-13 NMR spectroscopy, high-resolution mass spectroscopy (HRMS), and polarimetry. The absolute configuration of the optically active derivatives was confirmed by quantum chemical time-dependent density functional theory (TD-DFT) calculations of the theoretical electronic circular dichroism (ECD) spectra and by single-crystal X-ray structure analysis of a synthesis intermediate.

The construction of benzylic all-carbon quaternary stereocenters, which are ubiquitous in biomolecules and drugs, is a task of high practical significance. Herein, we disclose a highly efficient one-pot method of constructing all-carbon quaternary structural units from aryl ketones, revealing that the entire process involves three consecutive chemical events, namely nucleophilic addition, Meinwald 1,2-hydrogen migration, and alkylation. Interestingly, dimerization of acetophenones results in formation of 2,4-diarylfurans under the employed conditions rather than the quaternary carbon products.

A series of 2-(1-(2,4-dibenzhydrylnaphthylimino) ethyl)6-(1-(arylimino) ethyl) pyridyliron(II) complexes (Fe1-Fe5) was synthesized and characterized. The molecular structure of the representative Fe2 was determined by single-crystal X-ray diffraction, revealing a distorted pseudo-square-pyramidal geometry around the iron center. On activation with eithermethyl aluminoxane (MAO) or modified methylaluminoxane (MMAO), all these iron complex precatalysts performed with high activities (up to 1.58 x 10(7) g (PE) mol(-1) (Fe) h(-1)) toward ethylene polymerization, producing highly linear polyethylenes with highmolecular weight and bimodal distribution, which was in accordance with high temperature C-13 NMR, high T-m values (T-m similar to 130 degrees C) and the GPC curves of the obtained polyethylenes. Meanwhile, DFT calculation results also showed the good correlation between net charges on iron and experimental activities. Compared with previous bis(imino) pyridyliron analogues, the current iron complexes containing the benzhydrylnaphthyl groups exhibited relatively higher activities and better thermalstability at elevated temperatures, especially at 80 degrees C as the industrial operating temperature, and still showed high activities toward ethylene polymerization up to 8.57 x 10(6) g (PE) mol(-1) (Fe) h(-1) in the presence of co-catalyst MMAO. In addition, these iron complex precatalysts all exhibited long lifetimes. (C) 2017 Wiley Periodicals, Inc.

A two-photon ratiometric fluorescent probe (Mito-N) has been developed for monitoring mitochondrial nitric oxide (NO) in vivo. Mito-N exhibited excellent selectivity and sensitivity toward NO among various ROS/RNS. The successful two-photon imaging of mitochondrial NO proved that Mito-N is a powerful noninvasive imaging tool in living systems.

A series of triphenylethylene-based luminophoric molecules were efficiently synthesized. The substituent effect of the fluorophores on their photophysical properties was then investigated. Consequently, it was found that longer conjugated system and larger molecular dipole of the donor–π–acceptor fluorophores could result in bathochromic shifts of UV–vis absorption and emission bands, so do the Stokes shifts. Especially, full-color fluorescent emissions in both solution and solid states could be achieved by changing conjugation length and substituents with different electron-donating or accepting abilities in the triphenylethylene skeleton. The density functional theory calculations further demonstrated that with the increase of the electron-donating or accepting abilities of the substituents, the energy gaps of the fluorophores gradually decreased, which elucidated the substituent effect of the organic fluorophores on their photophysical properties.

A series of peripheral dendron-incorporating 1,4-bis[2,2-bis(4-alkoxyphenyl)vinyl] benzenes with aggregation-induced emission properties were synthesized. As the generation of the dendrons increased, there was an enhancement in the fluorescence emission of the corresponding fluorophore not only in the solid state but also in various solvent systems. The fluorescence quantum yields of the molecule with the largest dendons were up to 71% in the solid state and 66% in solution. The dendrons acted as a shell to the fluorophore core to prevent intermolecular pi-pi interactions and restrict the intramolecular rotations of the fluorophore, which improved the luminous intensity. This study shows that the incorporation of bulky dendrons is an effective way to increase the fluorescence emission efficiency of aggregation-induced emission fluorophores.

The newly prepared 8-(2-benzhydrylnaphthylimino)-5,6,7-trihydroquinoline derivatives (L1-L3) individually reacted with (DME) NiBr2 or NiCl2 to form their corresponding nickel bromide complexes (Ni1-Ni3) and nickel chloride complexes (Ni4-Ni6). These nickel complexes were fully characterized by FT-IR spectroscopy and elemental analysis as well as single crystal X-ray analysis. The representative molecular structures of Ni1 and Ni4, confirmed by single crystal X-ray diffraction, revealed a distorted octahedral geometry around nickel atom as the halo-bridged centro-symmetric dimers with formulae as L2Ni2X4 (X = Br, Ni1-Ni3; X = Cl, Ni4-Ni6). All nickel complexes, activated with either modified methylaluminoxane (MMAO) or diethylaluminiumchloride (Et2AlCl), exhibited high activities toward ethylene polymerization, producing branched polyethylene with low molecular weights. The obtained polyethylenes showed tail peaks in the high molecular weight portion according to the GPC curves due to the constrained geometry caused by the bulky 2-benzhydrylnaphthyl-substituted 8-arylimino-5,6,7-trihydroquinoline derivatives. (C) 2015 Elsevier B.V. All rights reserved.

Novel indolo-quinoline compounds were efficiently prepared via a Povarov-type reaction, and the structures were further modified by a Suzuki coupling reaction. The corresponding BF2-rigidified complexes were prepared and their spectroscopic properties were characterized with large Stokes shifts (up to 211 nm) and up to near-infrared (NIR) wavelength (667 nm). The synthetic complexes could be used as new fluorescent dyes.

An efficient method for the construction of cyclopropane-fused dihydroquinolines was established by a novel Povarov-type three-component reaction of aromatic aldehydes, anilines and cyclopropenes in the presence of trifluoromethanesulfonic acid. The reaction proceeded in a regioselective and diastereoselective manner. Furthermore, the dihy-droquinolines were smoothly converted to benzazepine derivatives via a ring opening/isomerization sequence, further expanding the synthetic scope.

An efficient Knoevenagel condensation reaction was used to construct a series of α-cyano-α,ω-diaryloligovinylenes, which show prominent fluorescence emission in the solid state. On investigating the effect of conjugation length on fluorescent properties, we found that the diene structure showed superior solid-state luminescence. Furthermore, the emission color could be adjusted by introducing donor or acceptor functional groups at the terminal aryl groups. Full-color emission in the visible region can be achieved by adding different functional groups to the α-cyano-α,ω-diaryldivinylene moiety. The structure-property relationships were elucidated and some observations such as the substitution position effects were discussed. These compounds have potential applications as full-color solid emissive candidates in material science and their simple structures allow them to be easily modified resulting in further interesting properties.

A pair of enantiomerically pure metallosquares based on linear platinum-diacetylene edges and tribenzotriquinacene corner units was synthesized. Their structures were characterized by (1) H-, (13) C- and (31) P NMR spectroscopy as well as MALDI-TOF mass spectrometry and circular dichroism. Based on DFT calculation, the optimized geometry possesses a distorted square conformation in which the four edges are not sitting on the same plane. The molecular square further self-assembled in the solid state to afford microspheres with diameter of approximately 300 nm, as determined by scanning electron microscopy.

The syntheses and structural properties of novel triscyclophanes that bear the rigid, bowl-shaped tribenzotriquinacene (TBTQ) core are reported. Condensation of the 2,3,6,7,10,11-hexakis(chloromethyl) derivative with catechols and 1,2-benzenedithiol gives rise to elongation of the three indane wings (intra-wing extension), whereas incorporation of resorcinol, hydroquinone, and 1,3- and 1,4-benzenedithiol units occurs by bridging the 3D bays of the TBTQ framework (inter-wing extension), yielding TBTQ-based cavitands. Constitutional and conformational details were studied by X-ray diffraction, VT-NMR spectroscopy, and molecular modeling. The bay-bridged TBTQ-based triscyclophanes bearing 1,3-dioxy-and 1,3-dithiophenylene units adopt globular and cone-like C-3-symmetrical shapes, respectively, with limited conformational flexibility. Baybridging by 1,4-dioxy- and 1,4-dithiophenylene units generates a more complanate coverage of the bowl face with even less conformational flexibility.

A number of three-fold C3v -symmetrical tribenzotriquinacene (TBTQ) cavitands were synthesized by a "metamorphosis-to-half" strategy, employing six-fold etherification reactions between the hexakis(chloromethyl)-TBTQ intermediate 2 a and various 5-functionalized resorcinols. X-ray structure analyses of single crystals of the cavitands revealed limited rotational flexibility of the resorcinol bridging units, which enables an apical, nearly co-axial orientation of the three functional groups and, as a consequence, the construction of nanoscale cage-like molecules via covalent or coordination bonding. On this basis, two TBTQ-based hemicryptophanes were prepared from the TBTQ cavitands via covalent bond formation in good yields. A dumbbell-shaped TBTQ-based metallo-cryptophane was also synthesized in 34 % yield by a solvothermal reaction between cadmium nitrate and two equivalents of the TBTQ-cavitand triacid, as confirmed by single-crystal X-ray diffraction and MALDI-ToF mass spectrometry.

A new C 3v -symmetrical tribenzotriquinacene (TBTQ) derivative bearing six 8-quinolinyloxymethyl units at the rim of the bowl-shaped molecular framework is synthesized in a single-step by six-fold etherification of the corresponding hexakis(chloromethyl)-TBTQ precursor with 8-hydroxyquinoline. The resulting compound acts as a fluorescence chemosensor, producing a ‘turn-off’ fluorescent quenching response in the presence of Ag+ ions, and is highly selective toward Ag+ over other cations, such as Al3+, Ca2+, Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Ga3+, Hg2+, In3+, K+, Mg2+, Mn2+, Na+, Ni2+, Pb2+, Pd2+, and Zn2+. The fluorescence intensity change of the chemosensor solution can be clearly observed by the naked eye upon addition of silver salts.

The asymmetric synthesis of Szántay's amine (+)-2, the pivotal precursor for direct access to (+)-cycloclavine (1), is described for the first time in eleven steps with 19.7% overall yield from the commercially available 4-bromoindole. The strategy features an asymmetric induction by Ellman's sulfinimine and rhodium-catalysed isomerization of the C[double bond, length as m-dash]C bond.

We have developed a highly efficient aryl migration from an aryl ether to a carboxylic acid group through retro-Smiles rearrangement by visible-light photoredox catalysis at ambient temperature. Transition metals and a stoichiometric oxidant and base are avoided in the transformation. Inspired by the high efficiency of this transformation and the fundamental importance of C-O bond cleavage, we developed a novel approach to the C-O cleavage of a biaryl ether to form two phenolic compounds, as demonstrated by a one-pot, two-step gram-scale reaction under mild conditions. The aryl migration exhibits broad scope and can be applied to the synthesis of pharmaceutical compounds, such as guacetisal. Primary mechanistic studies indicate that the catalytic cycle occurs by a reductive quenching pathway.

Daphenylline, a novel daphniphyllum alkaloid, boasts a fused and bridging ring system coupled with six stereogenic centers. Here we present a direct and short construction of the ACDE ring system of daphenylline from the known 3-(2-bromophenyl)propanal in 10 steps and 17 % overall yield. The synthesis features an iron(III)-catalyzed aza-Cope-Mannich reaction, a self-terminating 6-exo-trig aryl radical-alkene cyclization and an intramolecular Friedel-Crafts acylation.

Tributylphosphine-catalyzed regioselective [3+2] cycloadditions between ethyl 5,5-diarylpenta2,3,4-trienoate 1 and various aromatic aldehydes 2 to produce a wide variety of polysubstituted 2,5-dihydrofurans 3, and between 1 and beta-unsubstituted alpha,beta-unsaturated carbonyl compounds 5 to give polysubstituted cyclopentenes 6 with a quaternary carbon center, are reported. In both cases the reaction partners approach each other via the sterically less hindered orientation to afford the target products in excellent regioselectivity. The reaction mechanism involved first the generation of a zwitterionic intermediate between the butatriene 1 and PBu3. For the formation of 2,5-dihydrofurans 3, the preferred cyclization mode encompassed the nucleophilic attack of the a-position of butatriene to the aldehydic carbon of 2, followed by the ring closure between the aldehydic oxygen of 2 and the gamma-position of butatriene, which is the first report of a normal [3+2] cycloaddition between cumulenes and aldehydes. For the formation of cyclopentenes 6, the reaction involved attack of the gamma-position of the butatriene to the electron-deficient beta-position of the alpha,beta-unsaturated carbonyl compounds 5, followed by the ring closure between the alpha-position of 5 and the a-position of butatriene, which shows a different regioselectivity to the previously reported [3+2] cycloadditions between butatriene and olefins.

A series of 2-(2-benzhydrylnaphthyliminomethyl)pyridine derivatives (L1-L3) was prepared and used to synthesize the corresponding bis-ligated nickel(II) halide complexes (Ni1-Ni6) in good yield. The molecular structures of representative complexes, namely the bromide Ni3 and the chloride complex Ni6, were confirmed by single crystal X-ray diffraction, and revealed a distorted octahedral geometry at nickel. Upon activation with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all nickel complex pre-catalysts exhibited high activities (up to 2.02 × 10(7) g(PE) mol(-1)(Ni) h(-1)) towards ethylene polymerization, producing branched polyethylene of low molecular weight and narrow polydispersity. The influence of the reaction parameters and the nature of the ligands on the catalytic behavior of the title nickel complexes were investigated.

An efficient formal synthesis of (±)-cycloclavine is achieved in seven steps and 27% overall yield from the known 2-(4-bromo-1-tosyl-1H-indol-3-yl)acetaldehyde. Key features include an iron(III)-catalyzed aza-Cope-Mannich cyclization and an intramolecular Heck reaction or a self-terminating 6-exo-trig aryl radical-alkene cyclization.

A highly chemoselective one-pot reaction has been developed involving a tandem semipinacol rearrangement/oxa-Michael addition sequence in which the in situ generated ketol diene intermediate can be transformed specifically to either the spiro- or fused-dihydrofuran products (see scheme). This one-pot tandem reaction represents a general synthetic methodology for the syntheses of the two different kinds of furan derivatives.

Graphene-xerogel-based Co–N cathode catalyst (Co–N-GX) for the oxygen reduction reaction (ORR) was prepared through a simple approach. The Co–N-GX shows a more positive onset potential, higher cathodic density for the ORR in alkaline media than graphene-sheet-based Co–N catalyst (Co–N-GS), highlighting the importance of high specific surface area for improving the ORR performance. The proposed approach makes the Co–N-GX catalyst a non-precious metal cathode catalyst for fuel cells. Keywords: Graphene xerogel, Electrocatalysts, Oxygen reduction reaction

Graphene based non precious metal catalysts for oxygen reduction reaction (ORR) has been successfully fabricated through pyrolysis of a mixture of Fe, Co salts, polyaniline, and reduced graphene oxide (rGO). The transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), Raman spectrum and X-ray photoelectron spectroscopy (XPS) analysis's indicated the transition metal nitrogen-containing moieties (M–Nx, M = Fe or/and Co, x = 2 or 4) could be embedded into the graphene sheets. The electrochemical measurements showed that the embedded M–Nx moieties could act as catalytic sites and boost the activity of catalysts in both acidic and alkaline medium. The effects of Fe and Co on electrochemical properties toward ORR were also investigated, and the results showed the binary metal FeCo–N–rGO was the most active ORR catalyst. Rotating disk electrode measurements revealed that, compared to a commercial Pt/C electrocatalyst (loading: 52.6 μg Pt cm−2), the half-wave potential of the resultant FeCo–N–rGO was 46 mV positive in alkaline medium and 119 mV negative in acidic medium. In addition, the FeCo–N–rGO catalyst was much more stable and tolerant to crossover effect than Pt/C. The above superiorities make it a promising candidate for substituting Pt-based nanomaterials as a cathode catalyst for ORR in fuel cells.

Two tribenzotriquinacene-based crown ethers, TBTQdibenio-24-crown-8 5 and-TBTQbenzo-21-crOwn-7 6, were prepared from the key TBTQ intermediate, 2,3-dihydroxy-4b,8b,12b,12d-tetramethyltribenzotriquinacene (13), which in turn was synthesized in six steps using two variants of our cyclodehydration method on a multigrarri scale. The host-guest complexation properties of the TBTQbased crown ethers 5 and 6 With a pataquat derivative, 16, and two secondary ammonium salts, 17 and 18, were studied by H-1 NMR spectroscopy and mass spectrometry. It was found that host 5 binds to the paraquat deriVative 16 as a 1:1 complex in CDCl3/CD3CN solution with an association constant K-a = (9.2 +/- 1.8) X 10(2) M-1, whereas no complexation was found for 17 and 18. In contrast, the TBTQcrown ether 6 assembles selectively with dibutylammonium hexafluorophosphate 18 as a 1:1 complex in CDCl3/CD3COCD3 [K-a = (5.0 +/- 1.4) X 10(2) M-1]; for which a threaded [2]pseudorotaxane structure is assumed.

Nickel halide complexes of the type L2NiX2 (Ni1–Ni6, X = Cl; Ni7–Ni12, X = Br) bearing 2-benzimidazolyl-N-arylquinoline-8-carboxamide derived ligands have been synthesized and characterized by IR spectroscopy and elemental analysis. The molecular structures of the representative nickel complexes Ni8 and Ni11 revealed a distorted octahedral geometry at the nickel center. Upon activation with Et2AlCl, all such nickel pre-catalysts exhibited high activities for ethylene oligomerization. Furthermore, in the presence of MAO, they were shown to perform with good activities for the vinyl polymerization of norbornene.

A convenient synthesis of polyoxygenated tetrahydrothiopyrans and thiepanes from various alditol derivatives with xylo, ribo, manno, gluco, galacto, and fuco configurations is described. The preparation started from the corresponding partially protected alditols and proceeded in a ‘one-pot’ manner to afford the final products in 80%–95% yield. Furthermore, thiosugar compounds 2b, 2d, and 2g were converted to the optically pure polyoxygenated cycloalkenes through Ramberg–Backlund reaction in moderate to good overall yield. The procedures can be used for the preparation of polyoxygenated thiosugars and cycloalkenes on a relatively large scale.

A facile and improved route for the synthesis of the orally active spiroindoline-based growth hormone secretagogue, MK-677 was described. The key step adopted the Fischer indole/reduction strategy. The preparation of the key intermediates N-protected piperidine carboxaldehyde 5 and the N-Boc-O-benzyl- d -serine (2) are also optimized.

A series of 2-[1-(2,6-dibenzhydryl-4-chlorophenylimino)ethyl]-6-[1-(arylimino)ethyl]pyridine ligands (L1–L5) as well as the ligand 2,6-bis[1-(2,6-dibenzhydryl-4-chloro-phenylimino)ethyl]pyridine (L6) were synthesized and reacted with FeCl2·4H2O to afford the iron(II) dichloride complexes [LFeCl2] (Fe1–Fe6). All new compounds were fully characterized by elemental and spectroscopic analysis, and the molecular structures of the complexes Fe1, Fe2 and Fe4 were determined by single-crystal X-ray diffraction, which revealed a pseudo-square-pyramidal geometry at iron. Upon activation with either MAO or MMAO, all iron pre-catalysts exhibited very high activity in ethylene polymerization with good thermal stability. To the best of our knowledge, the current system showed the highest activity amongst iron bis(imino)pyridine pre-catalysts reported to-date. The polymerization parameters were explored to determine the optimum conditions for catalytic activity, which were typically found to be 2500 eq. Al to Fe at 60 °C in the presence of MMAO, and 80 °C in the presence of MAO. The resultant polyethylene possessed a narrow molecular polydispersity index (PDI) consistent with the formation of single-site active species.

A series of new organic semiconductors based on s-indaceno[1,2-b:5,6-b′]dithiophene-4,9-dione was successfully synthesized and characterized. The electron withdrawing carbonyl group lowers the LUMO energy levels, leading to increased electronegativities, which is beneficial for high photo-stability in air. The n-alkyl substituted compounds, 1c and 1d, crystallize with the rigid coplanar systems packed into slipped face-to-face π-stacks. Interestingly, 1c and 1d also show liquid crystalline behaviors, which give highly ordered molecular packing over large area.

A simple oxidative cyclization reaction was used to construct new seven-ring-fused butterfly-shaped oligothiophene backbone: dibenzothieno[1,2-b:4,3-b′:6,7-b″:9,8-b″′]tetrathiophene. The new materials show high stability and strong solid state fluorescence. X-ray crystallography results reveal that they exist in 2-D stacked structures in their crystals.