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McMurry coupling is one of the most useful and convenient tools for the preparation of π-conjugated molecules. However, for the synthesis of strained macrocycles containing ethynylene linkages, reduction of ethynylene to vinylene linkage sometimes took place. Especially, for the synthesis of macrocyclic π-extended thiophene hexamers using McMurry coupling of dialdehyde 1 composed of three thienylene, two ethynylene, and two formyl groups, reduction of ethynylenes to vinylenes often takes place to produce unique products in a one-pot procedure, depending on very small steric and electronic effects such as reaction temperature, amounts of titanium reagent, and substituents of thiophene hexamers. The attractive structures and functional properties of reduced thiophene hexamers have been determined using X-ray analysis and OFET measurements.

We herein report a unique example of on-surface adaptive self-assembly. A pentagon-shaped macrocycle, cyclic [5]meta-phenyleneacetylene [5]CMPA, is trapped by the adaptive supramolecular network formed by an isosceles triangular molecule, alkoxy substituted dehydrobenzo[14]annulene [14]ISODBA at the liquid/graphite interface, leading to a highly ordered and large-area bicomponent self-assembled molecular network (SAMN), as revealed by scanning tunneling microscopy (STM).

Macrocyclic oligothiophenes and their π-expanded derivatives constitute versatile building blocks for the design of (supra)molecularly engineered active interfaces, owing to their structural, chemical, and optoelectronic properties. Here, it is demonstrated how resonant tunneling effect induces single molecular isomerization in a 2D crystal, self-assembled at solid-liquid interfaces under ambient conditions. Monolayers of a series of four π-expanded oligothiophene macrocycles are investigated by means of scanning tunneling microscopy and scanning tunneling spectroscopy (STS) at the interface between their octanoic acid solutions and the basal plane of highly oriented pyrolytic graphite. Current-voltage characteristics confirm the donor-type character of the macrocycles, with the highest occupied molecular orbital and the lowest unoccupied molecular orbital (LUMO) positions consistent with time-dependent density functional theory calculations. Cyclic STS measurements show the redox isomerization from Z,Z-8T6A to its isomer E,E-8T6A occurring in the 2D crystal, due to the formation of a negatively charged species when the tunneling current is in resonance with the LUMO of the macrocycle.

π-Expanded oligothienylene macrocycle with a large inner cavity incorporates fullerenes such as methano[60]fullerene (C61H2) and [70]fullerene (C70) inside to form Saturn-like complexes. Although the oligothiophene macrocycle weakly interacts with fullerenes in solution, it forms stable Saturn-like fullerene complexes in the solid state. X-ray analysis of the Saturn-like complexes exhibited short contacts between the sulfur atoms of the oligothiophene macrocycle and fullerene carbons, which hinder the rotation of fullerenes. As a result, the non-covalent interaction between the oligothiophene macrocycle and fullerenes was employed in crystal structure determination of fullerenes. UV–vis–NIR spectra of the Saturn-like complexes showed weak donor–acceptor interaction between the oligothiophene macrocycle and fullerenes.

Macrocyclic 10-mesityl-1,8-diphenylanthracene dimer 4 was synthesized by using the electron-transfer oxidation of Lipshutz cuprate derived from 1,8-bis(4-bromophenyl)-10-mesityl-anthracene 7 in moderate yield. This dimer 4 is a considerably fluorescent molecule (ΦF 0.40) with high thermal, photo, and air stability. The X-ray analysis of 4 revealed a unique structure with a small inner cavity which can incorporate a small molecule or atom. 1H NMR spectra in solution and emission spectra of 4 in the solid state showed that copper(I) ion was incorporated to form a 1:1 complex 4·CuOTf, whereas silver(I) ion only weakly interacted with 4 under similar conditions.

The construction of redox-active supramolecular assemblies based on star-shaped and radially expanded tetrathiafulvalene (TTF) oligomers with divergent and extended conjugation is summarized. Star-shaped TTF oligomers easily self-aggregate with a nanophase separation to produce supramolecular structures, and their TTF units stack face-to-face to form columnar structures using the fastener effect. Based on redox-active self-organizing supramolecular structures, conducting nanoobjects are constructed by doping of TTF oligomers with oxidants after the formation of such nanostructures. Although radical cations derived from TTF oligomers strongly interact in solution to produce a mixed-valence dimer and π-dimer, it seems to be difficult to produce nanoobjects of radical cations different from those of neutral TTF oligomers. In some cases, however, radical cations form nanostructured fibers and rods by controlling the supramolecular assembly, oxidation states, and counter anions employed.

Intramolecular interactions of face-to-face tetrathiafulvalenes (TTFs) in 1,8-bis(tetrathiafulvalenyl)naphthalene frameworks were investigated in neutral and cationic states. From X-ray analysis an...

The Diels–Alder reaction of 1,2-dihydropyridine derivatives (1-phenoxycarbonyl-1,2-dihydropyridine 1 or 1-methoxycarbonyl-1,2-dihydropyridine 4) with N-acryloyl (1S)-2,10-camphorsultam (1S)-2 {or N-acryloyl (1R)-2,10-camphorsultam (1R)-2} in the presence of Lewis acid, such as titanium tetrachloride, zirconium tetrachloride, and hafnium tetrachloride afforded the endo-cycloaddition product, 2-azabicyclo[2.2.2]octane derivatives in good yields with excellent diastereoselectivity. The absolute stereochemistry assignment of the endo-cycloaddition product (1S)-5a starting from N-acryloyl (1S)-2,10-camphorsultam (1S)-2 has been established to be (1S,4R,7S) and the reaction mechanism was proposed.

Octithiophene sterically segregated by annelation with bicyclo[2.2.2]octene (BCO) units was synthesized to study the unimolecular properties of longer oligothiophene dications. For the preparation of such longer oligomers, a new route for the synthesis of the monomer annelated with BCO unit at the 3,4-positions of thiophene ring was developed. Attempted synthesis of octithiophene 1(8T) fully annelated with BCO units was hampered by low solubility of the product, and octithiophene 2(8T) having octyl groups instead of the BCO units at the second rings from the both ends of 1(8T) was synthesized to solve the solubility problem. Neutral 2(8T) has a lower planarity due to the steric repulsion between the octyl substituents and the neighboring thiophene units. However, dication 2(8T)2+, which was obtained as a stable salt by chemical two-electron oxidation with NO+SbF6–, has a planar quinoid structure, as judged from a linear correlation between the inverse chain length and the absorption energy for 1(nT)2+ (n = 3,4,6) and 2(8T)2+. Based on the comparison with the calculated absorption spectra and the result of ESR inactive properties, 2(8T)2+ appears to have a singlet ground state with open-shell biradical character rather than a closed-shell singlet structure.

Fully conjugated π-expanded macrocyclic oligothiophenes with 24π to 180π electron systems have been synthesized using a modified McMurry coupling reaction as the key step. For the synthesis of cyclo[n](2,5-thienylene-ethynylene)s composed of thiophenes and acetylenes, bromination-dehydrobromination and double elimination procedure were employed. X-ray analyses of macrocyclic oligothiophenes with 24π, 60π, and 72π systems revealed unique molecular and packing structures, reflecting planar cyclic frameworks with medium to large inner cavities. All the giant macrocycles exhibit multistep reversible redox behavior with a fairly low first-oxidation potentials, reflecting their cyclic conjugation. The doping of macrocycles with iodine forms semiconductors owing to their π-donor properties and π–π stacking ability. Interestingly, 90π, 108π, and 120π systems self-aggregate in the solid state to form red nanofibers or petal structure, whereas 150π to 180π systems form red nanoparticles. The structures of fibrous aggregates and particles have been established by scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses. Furthermore, two-photon properties of 72π, 108π, 144π, and 180π systems show that the increasing π-conjugation leads to an increase in the two-photon absorption cross-section with magnitudes as high as 100 000 GM in the visible spectral region.

Cyclooctatetraene (COT), the first 4nπ-electron system to be studied, adopts an inherently nonplanar tub-shaped geometry of D2d symmetry with alternating single and double bonds, and hence behaves as a nonaromatic polyene rather than an antiaromatic compound. Recently, however, considerable 8π-antiaromatic paratropicity has been shown to be generated in planar COT rings even with the bond alternated D4h structure. In this review, we highlight recent theoretical and experimental studies on the antiaromaticity of hypothetical and actual planar COT. In addition, theoretically predicted triplet aromaticity and stacked aromaticity of planar COT are also briefly described.

Fully conjugated π-expanded macrocyclic oligothiophenes with 60π–180π electron systems have been synthesized using modified McMurry coupling reaction as a key step. X-ray analyses of 60π and 72π systems revealed unique molecular and packing structures, reflecting planar cyclic structures with large inner cavities. All giant macrocycles exhibit multi-step reversible redox behavior with fairly low first oxidation potentials, reflecting their cyclic conjugation. Doping of macrocycles with iodine forms semiconductors owing to their π-donor properties and π–π stacking ability. Interestingly, 90π and 120π systems self-aggregate in the solid state to form red nanofibers. The structures of fibrous aggregates have been established by SEM and AFM analyses. Furthermore, two-photon properties of 72π, 108π, 144π, and 180π systems show that the increasing π-conjugation leads to an increase in the two-photon absorption cross-section with magnitudes as high as 100,000 GM in the visible spectral region.

Self-assembly and nanostructure formation of tetrathiafulvalene (TTF) oligomers using S and π-π interactions are summarized. Thus, tris(TTF)-annulenes were prepared by palladium-catalyzed couplings of diethynyl-TTFs. Multi-functional TTF-annulenes show various chromic properties in solution and the nanofiber formation in the solid state. Interestingly, the diamagnetic responsibility of the [18]annulene can be employed for the fiber alignment in a magnetic field. Fur-thermore, flexible star-shaped TTF oligomers were prepared by Sonogashira coupling of iodo-TTF with ethynylbenzenes. The star-shaped TTFs show strong self-aggregation in solution. In the case of the star-shaped hexamer, hexagonally ordered one-dimensional nanofibers are constructed both in neutral and cationic states. The electric conductivity of the cation-radical fiber is 2 orders of magnitude higher than that of the cation-radical film.

Fully conjugated π-expanded macrocyclic oligothiophenes with 60π-, 90π-, 120π-, 150π-, and 180π-electron systems (1–5) were synthesized using modified McMurry coupling reaction as a key step. Compound 1 was converted into macrocyclic oligo(2,5-thienylene-ethynylene) 6 using bromination-dehydrobromination procedure. X-ray analysis of 1 revealed a unique molecular and packing structure, reflecting a round, planar shape with nanoscale inner cavity. Interestingly, 2 and 3 self-aggregate in the solid state to form nanowires. The structure of fibrous aggregates was established by scanning electron microscopic and atomic force microscopic analyses. Compounds 1–6 exhibit multi-step reversible redox behavior with fairly low first oxidation potentials, reflecting their cyclic conjugation. Doping of 1–3 with iodine gives semiconductors owing to their π-donor properties and π–π stacking ability. © 2007 Wiley Periodicals, Inc. 18:460–466, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20337

The photophysics of conjugated polymers has generally been explained based on the interactions between the component conjugated chromophores in a tangled chain. However, conjugated chromophores are entities with static and dynamic structural disorder, which directly affects the conjugated polymer photophysics. Here we demonstrate the impact of chain structure torsional disorder on the spectral characteristics for a macrocyclic oligothiophene 1, which is obscured in conventional linear conjugated chromophores by diverse structural disorders such as those in chromophore size and shape. We used simultaneous multiple fluorescence parameter measurement for a single molecule and quantum-mechanical calculations to show that within the fixed conjugation length across the entire ring an inhomogeneity from torsional disorder in the structure of 1 plays a crucial role in causing its energetic disorder, which affords the spectral broadening of ∼220 meV. The torsional disorder in 1 fluctuated on the time scale of hundreds of milliseconds, typically accompanied by spectral drifts on the order of ∼10 meV. The fluctuations could generate torsional defects and change the electronic structure of 1 associated with the ring symmetry. These findings disclose the fundamental nature of conjugated chromophore that is the most elementary spectroscopic unit in conjugated polymers and suggest the importance of engineering structural disorder to optimize polymer-based device photophysics. Additionally, we combined defocused wide-field fluorescence microscopy and linear dichroism obtained from the simultaneous measurements to show that 1 emits polarized light with a changing polarization direction based on the torsional disorder fluctuations.

An efficient method for the homocoupling of aryl halides by electron-transfer oxidation of Lipshutz cuprates (Ar2Cu(CN)Li2) with organic electron acceptors is disclosed. Thus, various types of Lipshutz cuprates are prepared by successive treatment of aryl or heteroaryl bromides with tert-butyllithium and CuCN. The electron-transfer oxidation of Lipshutz cuprates with p-benzoquinones proceeds smoothly to afford the corresponding homocoupling products in moderate to good yields. Furthermore, it can be applied to the construction of either thiophene- or benzene-fused 10-membered ring cyclophanes. For the synthesis of 10-membered cyclophanes, the linear C-Cu-C structure of Lipshutz cuprates should be maintained in the dimetallacyclic intermediates, producing the large ring cyclophanes efficiently. The X-ray analysis of the cyclophanes reveals that the difference in the bridging atoms results in the different conformations of the macrocyclic rings. Thus, the silicon-bridged cyclophane 5a adopts a D2-symmetric structure with a twisted rhombic arrangement of four thiophene rings, whereas the methylene- and oxygen-bridged cyclophanes 5b and 5c possess C2h- and C2-symmetric structures with chair- and boatlike conformations, respectively. The 1H NMR spectrum of C2-symmetric 5c is temperature-dependent, and the activation energy (DeltaG) for the conformational change is 10.1 kcal/mol.

The crystal structures, electronic and magnetic properties of conducting molecular magnets developed in our group are reviewed. (DMET)2FeBr4 is composed of alternating stacks of quasi-one-dimensional (1D) donor sheets and square lattice magnetic anion sheets. This salt undergoes an SDW transition of the donor layer at 40 K and an antiferromagnetic transition of Fe3+ spins on the anion layer at 3.7 K. The one-to-one correspondence of the anomalies appearing on the magnetization curves with those on the magnetoresistance supports the presence of the π–d interaction. (EDO–TTFI2)2[M(mnt)2] (M=Ni,Pt) consists of 1D chains of conducting donors and magnetic anions aligned in parallel. These salts show metallic conductivity accompanied with a metal–insulator transition around 90 K. Localized spins on the anions behave as a 1D ferromagnet, whose origin is explained by McConnell's first model. The properties of related materials, (EDTDM)2FeBr4, (EDS–TTF)2FeBr4 and (EDO–TTFBr2)2FeBr4, are also presented.

Palladium(II)- or copper(II)-catalyzed homo-coupling reaction of either trimethylstannyltetrathiafulvalene or tetrathiafulvalenylzinc chloride produces symmetrical bitetrathiafulvalenes (bi-TTFs) in good yields, whereas palladium(0)-catalyzed cross-coupling reaction of tetrathiafulvalenylzinc chloride with 4-iodotetrathiafulvalenes leads to the corresponding unsymmetrically substituted bi-TTFs in moderate-to-high yields. The X-ray analysis of bi-TTF derivatives showed planar structures, and the cyclic voltammetry suggested that bi-TTFs have good donor ability comparable to that of BEDT-TTF. The symmetrical bi-TTFs formed the corresponding CT-complexes and cation radical salts. These CT-complexes and radical salts were found to be metallic or semiconducting, reflecting the effect of stoichiometry control in the dimeric TTF system. The X-ray structures of two cation radical salts revealed a unique stacking, and the precise conducting path in BEDO-bi-TTF·ClO4 was discussed on the basis of MO calculations.

Two structurally related diferrocenyl [10]annulenes have been examined over the range 90≤ T ≤370 K by temperature dependent 57 Fe Mossbauer effect (ME) spectroscopy. While the hyperfine interaction parameters [isomer shift (IS) and quadrupole splitting (QS)], and their temperature dependencies are very similar to those which have been reported earlier for similar ferrocenyl complexes, the vibrational anisotropy of the iron atom motion is diagnostic of a cofacial interaction of the two cyclopentadienyl rings in the 2,10-diferrocenyl compound, and absent in the 2,7-diferrocenyl homologue. These results are compared with the corresponding behavior of the 1,5- and 1,8-diferrocenylnaphthalene compounds reported earlier.

A new and general method for preparing Fischer-type alkoxycarbene complexes 1 is reported. This method involves the alkylation of acylate complexes 7 with alkyldiphenylsulfonium salts 10 with a variety of functionalized alkyl groups. The alkylation of tetramethylammonium pentacarbonyl(1-oxyalkylidene)chromate(0) 7a-c, tetramethylammonium pentacarbonyl(1-oxymethylidene)molybdate(0) 7d, and pentacarbonyl(1-oxymethylidene)tungstate(0) 7e with alkyldiphenylsulfonium salts 10 proceeded smoothly under mild conditions to give the corresponding alkoxycarbene complexes 12-39 in good to high yields. Competitive alkylation of 7a with methyl-11 and isopropyldiphenylsulfonium tetrafluoroborate 40 shows a higher reactivity of the isopropyl group, suggesting the participation of an S-O sulfurane intermediate 41.

2,10-Diferrocenyl- and 2,5,7,10-tetraferrocenyl-1,6-methano[10]annulenes, in which the ferrocene nuclei are held proximate and cofacial, have been synthesized by using the palladium-catalyzed cross-coupling reaction of ferrocenylzinc chloride with 2,10-dibromo- and 2,5,7,10-tetrabromo-1,6-methano[10]annulenes. The structures of the face-to-face fixed ferrocene systems were determined by X-ray analysis. Cyclic voltammetric measurements of diferrocenyl- and tetraferrocenyl-1,6-methano[10]annulenes show two and three redox waves, respectively, reflecting the through-space and through-bond interactions of the ferrocene nuclei.

A series of 2,5-di(2-thienyl)-N-methylpyrrole derivatives 1a-1d with methylthio end-capping groups and electron-donating substituents at the 3-position of the thiophene rings was synthesized, and the effects of the substituents on the structure, stability, and π-dimerization ability of the radical cation were investigated using UV-vis-NIR and electron spin resonance spectra and density functional theory (DFT) calculations. Among the electron-donating methyl, methoxy, and methylthio substituents, the methoxy derivative 1c gave the most stable radical cation, which persisted in dichloromethane at room temperature under nitrogen for several hours without any apparent decomposition. In addition, 1c(•+) had the largest π-dimerization enthalpy among 1a(•+)-1d(•+). DFT calculations with the M06-2X method revealed that methyl and methylthio derivatives 1b(•+) and 1d(•+) as well as 1c(•+) adopt a cis-cis conformation, in contrast to the trans-trans conformer of unsubstituted 1a(•+), while the π-dimers of all of these compounds were shown to have a cis-cis conformation. On the basis of further detailed analyses, the preformed cis-cis conformation and the weaker intramolecular and intermolecular steric repulsions were considered to explain why 1c(•+) has the largest π-dimerization enthalpy.

The chemistry of fullerenes has expanded very rapidly in recent years. Since C60 possesses considerably high electron affinity and low ionization potential, this molecule shows a high reactivity to organic reagents to give a variety of adducts. This review summarizes six types of reactions of C60, i.e., cycloadditions, ionic additions, radical additions, halogenations, hydrogenations, and transition-metal-complex formations. The cycloadditions of C60 have been studied very extensively to produce numbers of fullerenes with various substituents. Therefore, these reactions have been classified into [1+2]-, [2+2]-, [3+2]-, [4+2] cycloadditions and the ene reaction. In addition to the reactions of C60, some reactions of C70 have been described.

An efficient method for the formation of macrocyclic dilactones via cyclization of (w-carboxyalkyl)diphenylsulfonium salts 3 containing an ester linkage under mild conditions is described. These sulfonium salts 3 were cyclized in the presence of cesium carbonate under high-dilution conditions to give 11- to 16-membered dilactones 4 in good yields. The cyclization of sulfonium salt 22 was successfully carried out for the synthesis of 11-membered dilactonic pyrrolizidine alkaloid, 13,13-dimethyl-1,2-didehydrocrotalanine 23

Nonaphenylenes and dodecaphenylenes have been synthesized by using electron-transfer oxidation of Lipshutz cuprates with duroquinone. Oxidation of the Lipshutz cuprate derived from 4,4''-dibromo-o-terphenyl 3a in THF produced nonaphenylene 1a in 46% yield, whereas the similar oxidation of the Lipshutz cuprates derived from 4,4''-diiodo-4',5'-dialkyl-o-terphenyls 3b-d in ether afforded the corresponding nonaphenylenes 1b-d and dodecaphenylenes 2b-d in moderate total yields. In the case of 4,4''-diiodo-4',5'-didodecyloxy-o-terphenyl 3e as the starting material, oxidation of the corresponding Lipshutz cuprate in ether or THF only led to the formation of nonaphenylene 1e. Both nonaphenylenes 1a-e and dodecaphenylenes 2b-d are unreactive to light, atmospheric oxygen, and prolonged heating. These oligophenylenes showed strong UV absorption and fluorescent emission and exhibited some redox properties on CV analysis. Moreover, hexadodecyloxynonaphenylene 1e exhibits different nanostructures on the surface and in solution to form a film by casting a solution of 1e in cyclohexane, benzene, chloroform, THF, or diisopropyl ether (IPE) and nanofibers from IPE-MeOH (1:1), indicating different absorption and emission spectra and XRD patterns. The absorption maxima of THF solution, fiber, and film are in the order of 1e film (315 nm)fiber (302 nm)solution (295 nm), whereas the emission maxima are in the order of 1e fiber (425 m)solution (418 nm)film (401 nm). XRD analysis revealed that 1e aligns laterally on a glass or silicon surface to form a thin film with a lamella structure; however, it forms a nanofiber with a Lego-like stacking structure without pi-pi stacking interaction of the aromatic rings. Reflecting the different nanostructures of the 1e film and fiber, a spin-coated 1e film is found to be effective in detecting the vapor of explosives due to the intercalation of nitroaromatics to the cracked surface of the loosely stacked 1e. In contrast, the 1e fiber is not effective in detection of nitroaromatics but exhibits fluorescence anisotropy. The maximum fluorescence intensity is obtained in a direction perpendicular to the longitudinal axis of the fiber, indicating the stacking direction to be parallel to the longitudinal axis of the fiber.

The vinylogues of 14,14-dicyano-5,10-dimethyl-6,8-bisdehydrotridecafulvene have been synthesized and the effect of increasing exocyclic double bonds upon the paratropicity of the thirteen-membered ring is discussed by comparing the polarizability of 2,2-dicyanovinyl, 4,4-dicyano-1,3-butadienyl, and 6,6-dicyano-1,3,5-hexatrienyl groups.

Reduction of NiX2(PPh3)2 with zinc in the presence of Et4NI gives a nickel catalyst which has been proven to be useful for the coupling of aryl halides. This nickel catalyst can be prepared in THF without an additional triphenylphosphine and is effective for the homocoupling of aryl chlorides, bromides, and iodides to produce biaryls and bipyridines in good yields. The reported new approach provides a simple access to novel derivatives of biaryls and bipyridines.

New Synthetic methods for preparing highly unsaturated compounds are developed by using the nickel-catalyzed cyclooligomerization of cumulenes, carbenoids, and benzocyclobutadiene, and the nickel-catalyzed Ullmann coupling of organic halides. [3] Cumulenes (butatrienes), which are generated in situ from various precursors, react with nickel (0) complexes to produce [4] radialenes in benzene and THF or [6] radialenes in DMF. The formation of dimers and trimers depends on the solvent used. Reaction of [5] cumulenes (hexapentaenes) with Ni (CO)2 (PPh3)2 yields very unique compounds containing radialene frameworks. Furthermore, reaction of nickel carbenoids proceeds formally as a cyclooligomerization of the carbene center to give [3] -, [4] -, and [5] radialenes. This one-step method has been applied to the synthesis of radialenes containing functional groups. The nickel-catalyzed Ullmann coupling of vinyl halides can be also achieved to give novel π-electron systems. Nickel-mediated synthesis of trimers of benzocyclobutadiene is demonstrated with mechanistic explanation.

Surface discharge that induces nonequilibrium two-dimensional plasma was employed to deposit a ZnO film on a poly(ethylene terephthalate) (PET) substrate. The discharge energy was easily tuned by controlling the grid pattern on the electrode as well as the input AC bias. After irradiating a plasma to the precursor precoated on a substrate for 3 min, a hexagonal ZnO single phase was obtained. The crystallization was restricted within the selective area adjacent to the plasma to leave a clear step after washing the substrate in water. The technique was further developed into direct patterning in film formation.

Sterically congested pyrrole-fused tetrathiafulvalene (TTF) decamer 4 was designed and synthesized via the SNAr reaction of decafluorobiphenyl with the corresponding pyrrolyl sodium salt, which formed amorphous spin-coated films showing good conductivity of up to 4.4 S cm−1 after iodine doping as the result of multi-dimensional π–π stacking between the TTF units.

The acetylenic analogs of malachite green, crystal violet, and their related compounds have been synthesized to examine an effect of an acetylenic bond on a dye system.

Dimethylbisdehydrotridecafulvene derivatives bearing various substituents at the exocyclic bond have been synthesized and the inductive effect of substituents upon the tropicity of the thirteen-membered ring is discussed on the basis of the spectral data.

Treatment of substituted octa-2,6-dien-4-yne-1,8-dial derivatives with CF3COOH gave cyclopentadiene, thiophene, or isobenzothiophene derivatives. Formation of an 18-membered cyclic ether was observed in the case of octa-2,7-dien-4-yne-1,6-diol derivative.

The cyclic dimerization of 1,7-disubstituted-1-oxo-2,4,6-nonatrien-8-ynes on treatment with a suspension of potassium hydroxide in liquid ammonia to give tetrasubstituted 18-membered cyclic glycols has been achieved. The cyclic glycols could be converted into 3,9,12,18-tetrasubstituted 1,10-bisdehydro[18]annulenes which were found to be conformationally stable and strongly diatropic.

Zerovalent nickel complex generated in situ by reduction of NiBr2(PPh3)2 with zinc powder in the presence of Et4NI was found to be an effective catalyst for homo-coupling of benzyl halides. The catalytic reactions proceeded smoothly in various solvents under mild conditions to afford dehalogenative-coupling products in good to high yields.

While 5-phenyltricyclo[7.4.1.03,6]tetradecahexaenyl anion, an anionic member of [4n]annuleno[4n]annulene, is moderately diatropic, 3-phenyltricyclo[7.4.1.02,5]tetradecahexaenyl anion appears atropic.

1,6,12,17-Tetraphenyl-2,4,13,15-tetrakisdehydro[22]annulene has been synthesized. The sparlingly soluble tetrakisdehydro[22]annulene was found to be conformationally stable and strongly diatropic.