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Two novel coordination compounds of cadmium, [Cd2L1(ssal)2(H2O)3]2·10H2O (1) and {[Cd2L1(dca)4(H2O)]·H2O}n (2) (where L1 = 2,2′,2″-(1-(pyridin-2-ylmethyl)imidazolidine-2,4,5-triyltripyridine), ssal...

N-Phenylbenzenesulfonamides exist preferentially in (+)- or (−)-synclinal conformations, which place the aromatic rings at both ends in the same direction with a twist. We have systematically analyzed the crystal structure of secondary aromatic sulfonamides bearing methyl, ethyl, and/or methoxy groups on the benzene rings. Intermolecular hydrogen bonding between the sulfonamide protons and sulfonyl oxygens was observed in 81 out of 85 crystals. The intermolecular hydrogen-bonding patterns could be classified into four types, i.e. Dimeric, Zigzag, Helical, and Straight patterns, with retention of the synclinal conformation of the sulfonamide moiety. We investigated the relationship between the hydrogen-bonding pattern and the proportion of the compounds that show chiral crystallization. On the basis of our classification of the intermolecular hydrogen bonds of aromatic sulfonamides, the crystals with Dimeric and Zigzag patterns, which both have enantiomeric synclinal conformers, intrinsically become achira...

Three dithienobenzimidazole derivative monomers (M1, M2, and M3) were prepared, where M3 was obtained by the oxidation of M1 and identified by the X-ray crystallographic analysis. π-Conjugated homopolymers (P1-0, P2-0, and P3-0) and copolymers (P1-2, P3-1, and P3-2) were synthesized by the palladium-catalyzed coupling polymerizations of M1, M2, and M3. The absorption spectra of the reference compounds (fused R1 and non-fused R2), in conjunction with the optimized ground state structure, certified the importance of the fused dithienobenzimidazole skeleton to increase the effective conjugation length of the polymers. On the basis of the absorption and emission spectra of the π-conjugated polymers in CHCl3, the influence of the thiophene-S,S-dioxide as well as the comonomer structure were investigated to find out that P3-0 and P3-2 exhibited peak maxima at the relatively longer wavelength region due to the donor-acceptor interaction. In addition, the protonation of the imidazole imine group further tuned the optical properties of the π-conjugated polymers by promoting the charge transfer interaction along the polymer main chain, which was supported by the theoretical calculations in detail.

Fused imidazole monomers (1b, 1i, and 2b) having the octyl group were synthesized by the microwave-assisted intramolecular direct arylation, which were subjected to the cross-coupling polymerization. For obtaining π-conjugated polymers with better solubility, fused imidazole monomers (si-1b and si-3b) having the bulky trisiloxane-terminated decyl chain were likewise synthesized and polymerized. On the basis of absorption and emission spectra of obtained π-conjugated polymers in conjunction with the X-ray crystal structure of model compounds and theoretical calculation, the fused structure and coupling partner were found to affect the optical properties in CHCl3 solution as a result of steric and electronic factors. The spectroscopic measurements in film revealed that the bulky trisiloxane group helps π-conjugated polymers to form the π-stacked structure upon thermal annealing. The proton doping experiment was also carried out to find out that the protonation of imidazole nitrogen results in the different ...

The incorporation of flexible aliphatic units into otherwise rigid aromatic foldamer sequences may result in different outcomes. The flexible units may have conformational preferences of their own that can be expressed orthogonally to those of the aromatic units. Alternatively, the latter may dictate their folding behavior onto the former. Hybrid aliphatic–aromatic peptidic oligomers combining oxazole-based (O) and quinoline-based (Q) amino acids have been synthesized, and their folding behavior has been investigated in solution by NMR spectroscopy and CD spectroscopy, and in the solid state by X-ray crystallography. Sequences based on the OQQ repeat motif were shown to fold into a canonical aromatic helix motif dominated by the preferences of the quinoline, whereas sequences based on OQ repetitions preferred to fold into a herringbone helix in which the conformational preference of the oxazole units is also expressed.

Two adamantane-bridged tripodal trisimidazolium or trisbenzimidazolium salts were designed as C3v-symmetrical tricarbene ligands and synthesized in good yields. The reaction of the tripodal trisazolium salt precursors with silver oxide provided trisilver hexacarbene complexes bearing a three-dimensional framework. Multinuclear NMR spectroscopy and mass spectrometry data showed that the complexes were symmetric structures of two tricarbene ligands, three metal ions, and three counter anions. X-ray crystallographic analyses revealed that both complex cations adopted a highly twisted conformation. The complex cations built from the trisimidazolium salts were arranged into columnar structures through CH/π interactions, which were assembled into a three-dimensional network structure by intermolecular CH/F interactions via hexafluorophosphate anions. The complex cations generated from the trisbenzimidazolium salts were aligned into columnar structures, which were arranged into a network structure through CH/π interactions. Solvents and counter anions were accommodated in the spaces of the crystalline lattices.

We have characterized a novel aluminum-based homometallic double complex salt, incorporating discrete octa-coordinated cationic [Al(G3)2](3+) and hexa-coordinated anionic [Al(TfO)4(OH)2](3-) complexes (G3 = triglyme, TfO = trifluoromethanesulfonate). X-ray crystallography, Raman spectra, and DFT calculations demonstrate extraordinary weak Al(3+) coordination in [Al(G3)2](3+).

Amide-bridged ladder poly(p-phenylene) was synthesized in two steps, through the polycondensation of aromatic diamines and dicarboxylic acid derivatives followed by palladium-catalyzed intramolecular direct arylation. The π-stacked assembly of the polymer in solution was investigated along with the single crystal X-ray structure analysis of a model oligomer.

Phenylenediurea dibenzoic acid derivatives 1, 2, 3, and 5 and an amide derivative 4 were synthesized, and their molecular structures were elucidated to be an S-shape by single crystal X-ray analysis. Crystals of 1 were obtained as a DMF solvate, while those of 2 and 3 were not. Sheet and ladder structures were created in the crystal packing of 1 and 3, and 2, respectively. Unlike the para-substituted diureas 1–3 which possessed meso-conformation, the meta-substituted diurea 5 exhibited helical-conformation in its crystal structure. The way of crystal packing of 4 is analogous to that of the corresponding dicarboxylic acid derivative 2. A water cluster of a chair-shaped hexagonal array of water molecules was created in the crystal structure of 4. Diureas 1 and 2 gave cocrystals with melamine recrystallized from DMF/ethyl acetate and DMF/H2O, respectively. Unusual zigzag tapes of a H-bonding network of melamine were created in both cocrystals. The zigzag tapes were connected with S-shaped diureas by H-bondi...

Three different types of coordination polymers, one-dimensional (1D) straight chain, 1D-columnar structure, and two-dimensional (2D) layer structure, have been prepared by the complexation of Ag(I) ions with bis(pyridyl) ligands linked by an aromatic sulfonamides and structurally characterized by single-crystal X-ray diffraction and thermogravimetric analysis. Structural analyses showed that the complexation of the 3-pyridyl ligand with AgOTf and the complexation of the 4-pyridyl ligand with AgBF4 in CHCl3/CH3CN resulted in the formation of 1D straight-chain polymers. In the complexation of the 3-pyridyl ligand with AgBF4 in CHCl3/CH3CN, the resulting continuous 1D columnar coordination polymers were formed containing a racemic mixture of left- and right-handed helices. Furthermore, the 2D-layer structure was constructed by the complexation of a 4-pyridyl ligand with AgSbF6 in CHCl3/MeOH.

We have performed single crystal X-ray diffraction analyses of two 1-alkyl-3-methylimidazolium hexafluorophosphate ([Cnmim]PF6) salts, [C1mim]PF6, and [C3mim]PF6. The thermodynamically metastable crystalline phase (β phase) of the former was obtained by crystallization from the melt in a capillary for the crystallographic analysis. Both the cation and the anion in the β phase of [C1mim]PF6 show higher point group symmetry than those in the stable α phase. This result is shown to be consistent with the fact that the melting point of the β polymorph (314 K) is significantly lower than that of the α polymorph (364 K). The crystal structure of [C3mim]PF6 seems to be typical of that characteristic of the crystals of imidazolium-based room temperature ionic liquids. The cation conformation is the one in between those characteristic of the crystal structures of [C2mim]PF6 and [C4mim]PF6. When taken together, all crystallographic data for the [Cnmim]PF6 series (n = 1–4) demonstrate the influence of the alkyl chai...

The reaction of 2-(2-alkynylphenyl)benz[d]imidazoles with molecular iodine constructed 5- and 6-membered rings as novel organic salts in high yield. The constituted number of ring systems was influenced by the substituent at the triple bond: 6-membered rings were formed from compounds bearing aryl substituents, whereas 5-membered ones were obtained from compounds with hydrogen or alkyl substituents. The products were obtained with triiodide as a counteranion; however, compounds with iodide were also obtainable under certain conditions. We also revealed that they had an iodine–iodine interaction included in halogen bonding between an iodo moiety of the cation and a triiodide or iodide of the counteranion. The iodine–iodine interaction was formed with greater preference than the electrostatic interaction between the cationic atom and triiodide or iodide.

Vinylogy is a widely accepted principle involving the transfer of electronic chemical character through a double bond, and many reactions have been developed by applying this concept. In contrast, phenylogy, which involves the connection of two substituents through a benzene ring, is rarely recognized as a related idea. In this article, we present synthesis and physical properties, including their structure and reactivity of phenylogous amides. This amide mimetic unit is relatively stable and easily prepared by the Hartwig–Buchwald amination reaction. The effect of the resonance was examined by means of crystallography, reactivity and UV–vis spectroscopy.

We report an enantioselective synthesis of the polyhydroxylated pyrrolidine alkaloid (+)-DMDP. The key steps in the synthesis were guanidinium ylide mediated asymmetric aziridination, stereospecific ring opening of trans-3-vinylaziridine-2-carboxylate with an oxygen nucleophile, iodine-mediated 5-endo-trig amino cyclization, and Prévost displacement. In addition, a potential common intermediate for the polyhydroxylated pyrrolizidine alkaloids (+)-hyacinthacine A(1) and (+)-1-epi-australine was synthesized from a diastereoisomeric cis-aziridine coformed in the asymmetric aziridination using the same strategy. A rationale for the diastereoselectivity observed for the iodine-mediated amino cyclization reactions is proposed on the basis of the heats of formation of the products.

The [5 + 2] cycloaddition reaction of 2-vinylaziridines with sulfonyl isocyanates proceeded smoothly under mild conditions, and various cyclic ureas were isolated in high yields. The remarkable solvent effect on the reaction was observed, and the preferential formation of the seven-membered ring occurred when the reaction was carried out in CH(2)Cl(2). The scope and limitation were studied, and the mechanism of this reaction was discussed. This study provides a new and simple method for the synthesis of seven-membered cyclic ureas.

In order to examine versatility of ureadicarboxylic acids as U-shaped building blocks for crystal engineering, their crystal structures and cocrystals with pyridine derivatives were investigated. H-bonding networks created by a sequential linking of H-bonded carboxylic acid dimers resulted in the formation of ladder-type networks in the crystals of N,N′-diethyl-N,N′-diphenylureadicarboxylic acid (2) and N,N′-diallyl-N,N′-diphenylureadicarboxylic acid (3). A zigzag type H-bonding network with wedging of water molecules into carboxy–carboxy H-bonding was observed for N,N′-dibenzyl-N,N′-diphenylureadicarboxylic acid (4). Cocrystals of N,N′-dimethyl-N,N′-diphenylureadicarboxylic acid (1) with 2,5-di(pyridine-4-yl)thiazolo[5,4-d]thiazole (5) and 2 with 4,4′-dipyridyl (6) afforded zigzag-type assembled structures. Two types of channel structures were created in the cocrystals of 1 and dipyridylurea (7) by inclusion of water molecules together with either methanol or ethanol. The former afforded a straight-type ...

Single crystal X-ray structures of three imidazolium salts were examined. In contrast to imidazolium salt 1 possessing an ester group which created a network of C H⋯halide–anion interactions with a linear array of imidazolium and the corresponding counter anions, unique network structures were observed in imidazolium salts 2 and 3 with long alkyl chains and with carboxy moieties, respectively. Water molecules were incorporated in their H-bonding networks. Water molecules were wedged into the two neighboring halide anions to create square units which acted as a bridge to connect the two adjacent C H⋯halide–anion networks of imidazolium moieties and counter anions.

A series of adamantane-based bisphenol molecules with structurally related V-shaped skeletons were designed to examine the influence of molecular shapes and steric hindrances for the molecular association and packing of individual molecules in crystalline lattices. Single crystal X-ray analysis revealed that multiple intermolecular hydrogen bonds were formed between the hydroxyl groups of the phenol moieties. Crystallographic analysis of 1,3-bis(4-hydroxy-3,5-dimethylphenyl)adamantane (1) indicated the creation of a one-dimensional (1D) zigzag polymer through hydrogen bonds. In the crystals of 1,3-bis(3-bromo-4-hydroxyphenyl)adamantane (2), infinite 1D polymers composed of cyclic frameworks were sustained by intermolecular hydrogen bonds. 1,3-Bis(3-chloro-4-hydroxyphenyl)adamantane (3) and 1,3-bis(4-hydroxyphenyl)adamantane (4) formed frameworks with channels containing chloroform molecules in the solid state. Continuous 1D polymers consisting of cyclic frameworks were generated in crystals 3a and 4a, and...

Novel optically active axially chiral amino acid and amino alcohols have been synthesized efficiently via lactam ring-opening, with the aid of an optically active alcohol, amidoaza[5]helicene 5, which has been readily prepared by an additive-ligand-free Pd catalyzed domino coupling reaction in a single step. The stereostructures of these chiral molecules have also been clarified.

Ligands that consist of pyridine rings linked by sulfonamide are simple and unique building blocks which form infinite polymers and networks via metal-coordination and hydrogen bonds (H-bonds). Single crystal X-ray analysis revealed that the complexation of bidentate ligands 1 and 2 bearing secondary sulfonamide with silver(I) ion results in the formation of [AgL2(OTf)] (1a), [Ag2(μ-L)2(OTf)2] (2a), and [AgL(OTf)]n (2b) complexes. The complex 1a assembled into extended one-dimensional (1D) chains through H-bonds between the N−H moieties of sulfonamide and nitrogen atom of pyridyl groups. These individual chains associated into a three-dimensional (3D) network structure via C−H···O interactions between pyridyl protons and the oxygen atom of sulfonamides. The complex 2a assembled into two-dimensional (2D) sheets through H-bonds between the N−H moieties of sulfonamide and H2O molecules. In the complex 2b, enantiopure continuous 1D chain [AgL(OTf)]n was formed. In these structures, the silver(I) centers have ...

Synthetic studies of two components of tubulysins, tubulin polymerization inhibitors are described. The highly stereoselective synthesis of tubuvaline methyl ester ( 2 ) was accomplished by 1,3-dipolar cycloaddition of nitrone d - 6 and acrylic acid derivatives 7 as a key step. The synthesis of tubuphenylalanine ( 3 ) was conducted by an aldol reaction of a boron enolate of ( S )-4-isopropyl-3-propionyl-2-oxazolidinone ( 13 ) with aldehyde 14 , readily prepared from phenylalanine, followed by Barton deoxygenation under radical conditions.

A cyclic trimer and a cyclic tetramer of m-aminobenzenesulfonic acid were obtained by one-pot synthesis using dichlorotriphenylphosphorane as a coupling reagent. Single crystal X-ray analysis revealed that all sulfonamide moieties of the cyclic sulfonamides adopted a synclinal conformation, and that multiple intermolecular hydrogen bonds were formed between the sulfonamide protons and the sulfonyl oxygens on the adjacent molecules. The cyclic trimer has three types of pseudopolymorph containing water, methanol, or acetonitrile molecules. The molecule in each crystal was bowl-shaped, and the enantiomeric pair of molecules existed in a discrete dimeric structure with or without a guest molecule in the cavity. Furthermore, the cyclic tetramer existed in a 1,3-alternate conformation with pseudo-S4-symmetry, and formed an infinite network structure through intermolecular hydrogen bonds.

Enantioselective C–C bond formation at an α-position of a nitrile group with an external electrophile can be realized, although in modest ee, with the aid of both the concerted process of an epoxysilane rearrangement and a carbamoyl group. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Four-component synthesis of nitroimine derivatives (3) via double nitro-Mannich reaction was carried out in which nitroalkane, two moles of aldehyde, and lithium hexamethyldisilazide (LHMDS) were coupled in one-pot. In situ generated N-trimethylsilylaldimine was reacted with nitroalkane dianion followed by the second addition of the resulting nitrogen anion to the aldimine and the subsequent elimination of bistrimethylsilylamine furnished nitoroimine. The reaction was proceeded with erythro selectivity.

An effective screening method combining parallel synthesis and solid-state CD measurements was established to identify achiral aromatic sulfonamides that show spontaneous resolution with rapidity. We found that 4 of the 12 achiral sulfonamides crystallized as chiral crystals through this method. The chirality of each sulfonamide was discriminated by solid-state CD spectra and Flack parameter in an X-ray analysis. Correspondence between the observed Cotton effect and the absolute configuration could be confirmed by time-dependent DFT calculations. [structure: see text]

The crystal structures of 1,2-bis(N-benzenesulfonylamino)benzenes with secondary and/or tertiary sulfonamide groups were determined by X-ray crystallographic analysis. Every Ar-sulfonamide group existed in synclinal conformation in the crystals even though it was secondary or tertiary. Each compound showed different types of hydrogen bonds in the crystal structure. 1,2-Bis(N-benzenesulfonylamino)benzene (1) formed two double hydrogen bonds connected to the next molecules, 1-(N-benzenesulfonylamino)-2-(N-benzenesulfonyl-N-methylamino)benzene (2) contained double hydrogen bond involved by both the sulfonamide moieties, 1,2-bis(N-4-toluenesulfonylamino)benzene (3) had both intra- and intermolecular hydrogen bonds, and 1-(N-methyl-N-4-toluenesulfonylamino)-2-(N-4-toluenesulfonylamino)benzene (4) had one double hydrogen bond involved by only one sulfonamide moiety. Sulfonamides 1 and 3 formed infinite arrays of the molecules, and sulfonamides 2 and 4 formed racemic dimer of their conformational enantiomers via the hydrogen bonds.

The title compound, C17H18N2S2, exhibits atrans–trans–trans–gauche+(tttg+) conformation with regard to the NH–CH2–CH2–CH2–NH bond sequence. In the crystal, molecules are connected by N—H...S=C and C—H...S=C hydrogen bonds, forming a herringbone arrangement along thec-axis direction. The two thioamide groups make dihedral angles of 43.0 (2) and 33.1 (2)° with the adjacent phenyl rings.

We characterized cromolyn sodium (CS) hydrates and evaluated their molecular states in low-dose formulations using Na-multiquantum magic-angle spinning (MQMAS) nuclear magnetic resonance (NMR) analysis. Two CS hydrates, low-water-content hydrated form and high-water-content hydrated form containing 2–3 and 5–6 hydrates, respectively, were prepared by humidification. Single-crystal X-ray diffraction and powder X-ray diffraction analysis revealed that these CS hydrates contained sodium channel structures and that water molecules were adsorbed on the sodium nucleus. 13C-cross-polarization/MAS NMR spectra of these hydrates revealed similar results, confirming that the water molecules were adsorbed not on the cromolyn skeletons but mainly on the sodium nucleus. In contrast, 23Na-MQMAS NMR analysis allowed us to clearly distinguish these hydrates without discernible effects from quadrupolar interaction. Thus, MQMAS NMR analysis is a valuable tool for evaluating salt drugs and their formulations. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:2738–2747, 2013

Treatment of 2-vinylaziridines of type (I) and (VI) with sulfonyl isocyanates in CH2Cl2 allows a new and simple access to 7-membered cyclic ureas.

We synthesized three series of imidazolium-based ionic liquids (ILs) containing cycloalkyl groups such as cyclopentyl, cyclohexyl, or cycloheptyl groups incorporating bis(trifluoromethanesulfonyl)amide anions and characterized them with respect to physicochemical properties and molecular reorientational dynamics. A comparison of the physicochemical properties revealed that cycloalkyl-substituted imidazolium ILs have higher densities, viscosities, and glass transition temperatures than the respective n-alkyl-substituted imidazolium ILs. Among three series, the cyclopentyl-substituted IL exhibits exceptionally lower viscosity. Observation of correlation times by (13)C NMR spectroscopy revealed that a remarkably lower viscosity for the cyclopentyl-substituted IL and a considerably higher viscosity for the cyclohexyl- and cycloheptyl-substituted ones are closely related to the respective reorientational motion of the cations. The cause of these distinctions is suggested to be attributed to the difference of activation energy for the conformational interconversion of their substituents.

The catalytic asymmetric Friedel-Crafts/protonation of indoles and pyrroles with α-substituted nitroalkenes to give the corresponding adducts in a highly anti-selective manner was achieved by an imidazoline-aminophenol (L2)-Cu complex. The anti-adducts could be successfully transformed to biochemically important α-substituted β-heteroarylalkylamines.

The total syntheses of tetrapeptides tubulysins D (1 b), U (1 c), and V (1 d), which are potent tubulin polymerization inhibitors, are described. The synthesis of Tuv (2), an unusual amino acid constituent of tubulysins, includes an 1,3-dipolar cycloaddition reaction of chiral nitrone D-6 derived from D-gulose with N-acryloyl camphor sultam (-)-9 employing the double asymmetric induction, whereas the synthesis of Tup (20), another unusual amino acid, involves a stereoselective Evans aldol reaction of (Z)-boron enolate generated from (S)-4-isopropyl-3-propionyl-2-oxazolidinone with N-protected phenylalaninal and a subsequent Barton deoxygenation protocol. We accomplished the total syntheses of tubulysins U (1 c) and V (1 d) by using these methodologies, in which the isoxazolidine ring was used as the effective protective group for γ-amido alcohol functionality. Furthermore, to understand the structure-activity relationship of tubulysins, we synthesized tubulysin D (1 b) and cyclo-tubulysin D (1 e) from 2-Me and 20, and ent-tubulysin D (ent-1 d) from ent-2-Me and ent-20, respectively. The preliminary results regarding their biological activities are also reported.

Adamantane-based macrocycles and a cage with aromatic ring moieties have been developed and structurally revealed by X-ray crystallographic analysis. The dimerized (1) and trimerized (2) macrocycles of binary molecules based on adamantane with acetylenic aromatic ring moieties were designed and effectively synthesized. Similarly, a cryptand-like macrobicyclic cage (3) was constructed from a trisubstituted adamantane derivative. Single-crystal X-ray analysis revealed that both cyclic compounds have nearly a rectangular shape with or without a solvent molecule in the cavity. The macrobicyclic cage has an inner space and accommodates a chloroform molecule via C-H...pi interactions. Macrocycles and cage encapsulate 1,3,5-trinitrobenzene (4) as an electron-poor guest in a one-to-one complex via charge-transfer interactions in a parallel fashion, and showed the formation of molecular networks such as columns, tubes, 2D layers, and 3D networks composed of two different types through noncovalent interactions in the solid state.

Four-component synthesis of nitroimine derivatives (3) via double nitro-Mannich reaction was carried out in which nitroalkane, two moles of aldehyde, and lithium hexamethyldisilazide (LHMDS) were coupled in one-pot. In situ generated N-trimethylsilylaldimine was reacted with nitroalkane dianion followed by the second addition of the resulting nitrogen anion to the aldimine and the subsequent elimination of bistrimethylsilylamine furnished nitoroimine. The reaction was proceeded with erythro selectivity.

Octahomotetraoxacalix[4]arenes bearing long alkyl chains on their lower rim were prepared. Ester 4a existed in a 1,2-alternate conformation in its crystal structure, which was examined by single-crystal X-ray diffraction analysis. To prepare liquid crystalline materials possessing calixarene moieties by self-assembling, carboxylic acid derivatives 5 were synthesized. Among them, 5c, the octadecyloxy derivative, showed smectic liquid crystal phase. Homooxacalixarenes 5 also formed liquid crystal phases with longer layer distances when two equivalent moles of 1,2-ethylenediamine were added as a linker. These phases were investigated with X-ray diffraction, differential scanning calorimetry, and polarized optical microscopy.

Perchlorate-doped 3-methoxythiophene oligomer was chemically synthesized, and its solutions were applied to produce films characterized by their gold-like luster which showed no degradation in the ambient atmosphere for at least one year. The oligomer is characterized by its good solvent-soluble, good film-forming, and moderate electrical conducting properties. More importantly, wide-angle and grazing incidence X-ray diffraction measurements revealed that the gold-like films have a compact periodic layered structure with a lamellar interlayer spacing of 1.10 nm and an intralayer spacing of 0.34 nm, though the oligomer involves no long alkyl chains. It was proposed that the strong gold-like luster could be related to the highly regular and compact nature of the lamellae in the oligomer films.

A low-molecular-mass molecule with no long alkyl chain, a mixed-valence 9,9′-dimethyl-3,3′-bicarbazyl, is self-assembled into highly-regular straight micro/nanotubes by the one-step electro-oxidation of its precursor, 9-methylcarbazole, in methanol without templates. The driving force of the tube formation is investigated.

The nickel-catalyzed [3 + 2 + 2] cycloaddition of ethyl cyclopropylideneacetate and conjugated enynes proceeded smoothly and divinylcycloheptadienes were isolated in high yields. The three-component cocyclization of ethyl cyclopropylideneacetate, conjugated enynes, and (trimethylsilyl)acetylene also proceeded in a highly selective manner to afford vinylcycloheptadienes, which were reacted with various dienophiles. This study provided a new, short-step synthesis of polycyclic compounds with cycloheptane skeleton.