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1 Introduction 2 Synthesis of Prismanes 3 Physical and Structural Properties of Prismanes 4 Chemical Reactivities of Prismanes 5 Properties of Cation, Radical and Anion Species of Cubane 6 Functionalization of Cubanes 7 Nitrocubanes 8 Transformation of Cubanes to other Cage Systems 9 Properties of Propellaprismanes 10 Toward Hexaprismane 11 Summary 12 Acknowledgment Keywords: prismane - columnar compound group; cubane synthesis; prismane synthesis; prismane chemical reactivities; cubane and prismane chemistry; cubane functionalization and anionic reactions; cubyl cation intermediates; cubane transformation and cage systems

Reduction of flash generated in a gas vent is of great concern for manufacturers of electronic parts. The present study proposes a theoretical model for flash generation through consideration of flow characteristics in a gas vent. The model predicts the factors controlling flash, i.e., material parameters such as zero-shear viscosity, crystallization temperature, thermal conductivity, and heat capacity, and process parameters such as injection and mold wall temperatures, packing pressure, and the clearance of a gas vent. On the other hand, we measure the amount of flash generated in the molding of poly(phenylene sulfide) (PPS) composites containing glass fiber and spherical fillers (CaCO3 or Al2O3). Flash reduces with decreasing size of spherical fillers. These experimental data are successfully interpreted using the flash model. Polym. Eng. Sci., 45:198–206, 2005. © 2005 Society of Plastics Engineers

Reduction of flash during injection molding is of great concern for manufacturers of electrical parts. In a previous report, we proposed a theoretical model for flash generation. The present study investigates the effect of processing conditions on flash generation and then attempts to analyze the flash data in terms of the flash model. Specifically, we carry out flow analyses to predict the temperature and pressure of materials when the flash generates. With the thus-computed parameters, and material properties such as melt viscosity and crystallization temperature, a flash parameter defined in the model is calculated. In the end, it is shown that the flash parameter is correlated with the length of flash generated under various processing conditions. POLYM. ENG. SCI. 45:238–247, 2005. © 2005 Society of Plastics Engineers

Previous work has elucidated that the wall slip velocity and viscosity of polymer melts influence the thickness uniformity of blown film. The present study investigates the effects of the stress dependence of wall slip, the shear thinning and the density on the uniformity. We have prepared high-density polyethylenes with a variety of molecular weight distributions, which have different rheological properties. Examination of the thickness uniformity of their blown film has shown that the uniformity is correlated with wall slip velocity, the stress dependence of the velocity, melt viscosity, shear thinning and density; the coefficient of the correlation is determined to be 0.990. The reason why the stress dependence of wall slip and the shear thinning affect the uniformity is explained in terms of polymer melt flow behavior in a die, while the effect of density is interpreted considering bubble fluctuation in the blow-up process. Polym. Eng. Sci. 44:965–972, 2004. © 2004 Society of Plastics Engineers.

One of the most important materials for blown film is high-density polyethylene (HDPE) with wide molecular weight distribution. First, we computed a wall stress at the entrance of a spiral groove in a particular die during blown film processing on a particular condition, to which a similar condition is widely utilized in a film works. The computed value is about 170 kPa, while the HDPE melt slips at die wall at stresses above approximately 50 kPa. The stress of 170 kPa is sufficiently large for the slip occurrence of the melt. Then, we investigated the effects of wall slip and melt viscosity on film thickness distribution in the circumferential direction: the distribution tends to decrease with decreasing wall slip and melt viscosity. This tendency is explained by considering flow distribution in a spiral mandrel die and polymer melt flow characteristics.

A p-chloranil dimer (pCh2) has been synthesized. The first reduction potential of pCh2 shifted to a more positive value than that observed for the p-chloranil monomer (pCh1) and was more negative t...

Under modified Eglinton oxidative coupling conditions, it is possible to generate 1,1′-diethynylferrocene in situ from a trimethylsilyl-protected precursor (I) and to react it with other terminal alkenes (III).

The first example of fuluvalene derivative containing two monocyclic large-membered rings, 1-(5,10-dimethyl-6,7,8,9-tetradehydrocyclotridecen-1-ylidene)-7,12-dimethyl-8,9,10,11-tetradehydrocyclopentadecene, has been synthesized. Examination of 1H and 13C NMR spectra indicates that the tridecapentadecafulvalene derivative shows no ring current effect but polyolefinic character.

An intramolecular coupling of 1,6-bis(5-oxohepta-1,3-dien-6-ynyl)cyclohepta-1,3,5-triene under Glaser conditions affords 12,15-dichloro-13,14-didehydro-1,6-methano[20]annulene-11,16-dione, which exhibits strong diatropicity in D2SO4, suggesting the formation of the highly delocalized dicationic species.

The title azafulvene analogs were synthesized by the reaction of the corresponding annulenones with N,N′-bis(trimethylsilyl)carbodiimide. The 1H NMR spectra reveal that these compounds show larger tropicity than the corresponding dicyanofulvenes and annulenones.

The first synthesis and the physical properties of diphenoquinonophanes is reported along with their spectral evidences.

Configurational and conformational isomerism in the bisdehydro[15]annulenones were studied in CDCl3 and CF3CO2D–CD2Cl2 solutions by 1H NMR spectroscopy. The 7,12-dimethyl compound with the initial “all-E” configuration isomerized in both media at ambient temperature to give an equilibrium mixture of isomers but the trimethyl derivatives retained their original configuration under the similar conditions. The charge distribution in the deuterated species was discussed on the basis of the 13C NMR spectra.

Synthesis of the title compound, 15-(5,10-dimethylcyclotrideca-2,4,10,12-tetraene-6,8-diynylidene)-6,11-dimethylcyclopentadeca-1,3,5,11,13-pentaene-7,9-diyne, is described. Examination of 1H and 13C NMR spectra indicated that the tridecapentadecafulvalene derivative shows no ring-current effect but did have polyolefinic character.

Synthesis of 9,22-diethoxy-13,18-dimethyl-14,15,16,17-tetradehydro-2,7-methano-1,8-diaza[22]annulene (9,22-diethoxy-13,18-dimethyl-2.7-methano-1,8-diazacyclodocosa-2,4,6,8,10,12,18,20,22-nonaene-14,16-diyne), is described. Examination of 1H NMR and electronic spectra indicates that the diaza[22]annulene shows no ring current effect but does show polyolefinic character despite the potential diatropic 22π-electron system. Attempts to prepare the higher analogues, diaza[24]- and -[26]annulenes are also described.

10,12-Bisdehydro-3-isopropyl-9,14-dimethyl[14]- and -11,16-dimethyl[16]annuleno[a]azulene in which the conjugated 14- and 16-membered rings are fused to azulene ring, have been synthesized. It was found that the fusion of azulene ring suppresses the diatropicity of [4n+2], 14π-electron system to a smaller extent than benzene ring.

Synthesis of 7,8:13,14-dibenzo-2,9,11-trisdehydro[16]annulene-1,4-dione is described. Attempts to prepare diaza[18]annulene derivatives by ring expansion of the dibenz[16]annulenedione and its dimethyl analog are also described. Examination of 1H NMR spectra indicates that the dibenz[16]annulenedione shows no ring current effect.

The cationic rearrangement of 1-bromo-4-[hydroxybis(4-methoxyphenyl)methyl]pentacyclo[4.3.0.02,5.03,8.04,7]nonane-9-spiro-2′-[1,3]dioxolane (1) in formic acid gave 4-bromo-1-formyloxy-10,10-bis(4-methoxyphenyl)pentacyclo[5.3.0.02,6.03,9.04,8]decane-5-spiro-2′-[1,3]dioxolane in 27% yield along with 5-bromo-9-formyloxy-10,10-bis(4-methoxyphenyl)pentacyclo[5.3.0.02,5.03,9.04,8]decane-6-spiro-2′-[1,3]dioxolane in 55% yield. The reaction of 1 with p-toluenesulfonic acid or hydrochloric acid in methanol also afforded 4-bromo-1-methoxy-10,10-bis(4-methoxyphenyl)pentacyclo[5.3.0.02,6.03,9.04,8]decane-5-spiro-2′-[1,3]dioxolane together with 5-bromo-9-methoxy-10,10-bis(4-methoxyphenyl)pentacyclo[5.3.0.02,5.03,9.04,8]decane-6-spiro-2′-[1,3]dioxolane. With respect to migration of the C4–C5 bond in the pentacyclo[4.3.0.02,5.03,8.04,7]nonane (homocubane) skeleton to pentacyclo[5.3.0.02,6.03,9.04,8]decane (D2h-bishmocubane), a rearrangement into the bishomocubane system in driven by a concomitant release of strain; also...

A series of (porphyrin)–(C≡C)2–C6H4–R1 (R1 = NO2, H, Me, and OMe) were synthesized by the oxidative coupling of ethynyl porphyrins and phenylacetylenes in the presence of copper(II) acetate in pyridine. Electronic and electrochemical spectra of the compounds with R1 = H, Me, and OMe are quite similar, while pronounced change was observed for the compound with R1 = NO2, especially for the meso-substituted one, indicating that intramolecular charge transfer is responsible for the difference.

The title annulenedione 8 was synthesized starting from 1-acetyl-6-(3-oxobut-1-enyl)cyclohepta-1,3,5-triene 25 by aldol condensation with (Z)-3-methylpent-2-en-4-ynal 26 to afford the dione 27 and then by another aldol condensation of the dione 27 with the aldehyde 26, followed by intramolecular oxidative coupling of the resulting acyclic diacetylene 28. Examination of the 1H NMR spectra indicated that compound 8 is paratropic in acidic media.

A bismethano-bridged bisdehydro[21]annulenone, tricyclo[15.4.1.16,11]tricosa-6,8,10,12,15,17,19,21-octaene-2,4-diyn-14-one, was synthesized. X-ray crystallography reveals the syn orientation of the two methano bridges. Two conformers are present in solution in a 97:3 ratio, the major isomer being the one existing in the crystalline state. Paratropicity of this compound in CDCl3 and in CF3CO2D is discussed.

The two isomers of tetrakisbridged dimethoxybiphenylophanes, 1 and 2, have been synthesized. With respect to the longest wavelength absorption bands due to the biphenyl chromophores, the cross-orientation isomer exhibited the marked bathochromic shift, while the parallel-orientation isomer the typical exciton splitting. Their transannular properties in solution were further confirmed by X-ray crystal analysis.

Syntheses of 7,8,9,10-tetradehydro-1,6:11,16-dimethano[21]annulen-19-one 11, 7,8,9,10-tetradehydro-18-methyl-1,6:11,16-dimethano[21]annulen-19-one 12, 7,8,9,10-tetradehydro-1,6:11,16-dimethano[23]annulen-19-one 13 and 7,8,9,10-tetradehydro-1,6:11,16-dimethano[25]annulen-21-one 14 are described. The influence of an introduction of two methano-bridges upon the structure and tropicity of the tetradehydro-[21]-, -[23]- and -[25]annulenone ring systems is discussed in view of the 1H NMR and electronic spectra of these annulenones as well as those of the corresponding monocyclic annulenones.

The isomeric mixture of 3,3′-dialkylbithiophenes with head-to-head (H-H) and head-to-tail (H-T) orientations was separated into each isomer by using preferential brominartion of the H-T isomer. This separation method proved to be useful for simultaneous preparation of the pure H-H and H-T bithiophenes which are inaccessable by other methods.

14-Methyl-10,12-bisdehydro-4,9-methano-1H-[17]annulen-1-one, 14-methyl-10,12-bisdehydro-4,9-methano-1H-[19]annulen-1-one, and 16-methyl-12,14-bisdehydro-6,11-methano-1H-[21]annulen-1-one, as well as their methylated and benzannelated derivatives, were synthesized and their tropic properties were studied by NMR and UV spectra under neutral and acidic conditions. The tropicity in these compounds was found to be lower than in their non-bridged monocyclic counterparts. Thus the methano-bridge works to decrease the planarity of the peripherally conjugated system.

Our recent studies on synthesis, stereochemical analysis, and tropicity of various dehydroannulenes, annulenones, annulenediones, cross-conjugated annulene derivatives, and heteraannulenes are reviewed. Our efforts consist mainly of the design and construction of novel peripherally conjugated systems and the exploration of the highest member in each series of compounds exhibiting tropicity.

Mono-, di-, and trimetallic Pd(II) complexes of the etheno-bridge porphyrin trimer 1 were prepared. It was found that the metalation of 1 first occurred in the inner porphyrin ring. The trimetallic Pd(II) trimer 6 exibited splitting of the Soret band and complete disappearance of the weak bands ranging from 600 to 1000 nm unlike the corresponding free-base and Ni(II) porphyrin trimers.

The title thiaanulenes have been synthesized through a double Wittig reaction of bis[(triphenylphosphonio)-methyl]sulfide dibromide with 6-ethynylcyclohepta-1,3,5-triene-1-carbaldehyde and/or its vinylogous aldehyde, followed by intramolecular oxidative coupling of the resulting bisethynyl sulfides. For each compound, two isomers have been isolated which differed in the geometry of their peripheral olefinic moieties. 1H NMR spectra revealed that some of the geometrical isomers consisted of two conformational isomers which differed in the relative disposition of the two methano bridges. One isomer for each of the dimethano-bridged thia[21]- and -[23]annulenes sustained ring current, while the other isomers as well as those for the thia[25]annulene did not.

Tris(octaethylporphyrin)s, in which two octaethylporphyrin (OEP) rings are connected with vinylene groups at α,γ- and α,β-meso positions of the central OEP ring, were synthesized. The tris(OEP)s have similar conformational and configurational structures to the corresponding vinylene group-connected bis(OEP). Examination of both 1H NMR and electronic absorption spectra of the tris(OEP)s showed the behavior reflecting the highly symmetrical structure and the mutual interaction between the three OEP rings through the vinylene linkages.

The catalytic partial hydrogenation of the 5,10-dimethyl-6,8-bisdehydro[13]annulenone using Pd–BaSO4 afforded the 5,10-dimethyl[13]annulenone together with two isomeric 5,10-dimethyl-6-dehydro[13]annulenones. The dimethyl[13]annulenone, which is the first example of a monocyclic non-dehydro annulenone derivative larger than tropone, was found to be atropic on the basis of 1H NMR spectra. Molecular mechanics studies indicate the extensive deviation of the molecular skeleton from planarity and help to explain the lack of peripheral conjugation. Attempts to obtain the [15]annulenone and the [17]annulenone from the bisdehydro[15]annulenone and the bisdehydro[17]annulenone, respectively, were unsuccessful.

An [11][13]fulvalene derivative, 13-(4,9-methanocycloundeca-2,4,6,8,10-pentaenylidene)-4,9-dimethylcyclotrideca-1,3,9,11-tetraene-5,7-diyne, has been synthesized. Examination of 1H and 13C NMR spectra indicates that the compound shows no detectable ring-current effect in nonpolar solvents arising from 10π- and 14π-electron systems, which is verified by X-ray crystallographic structural analysis. In a polar solvent, [2H6]dimethyl sulfoxide, a small contribution of the dipolar resonance structure is suggested.

2,2′-(Dihexyl-2,2′-bithienylidene-5,5′-diylidene)bis(propanedinitrile)s (dihexylbithienoquinonoid derivatives), in which two 3-hexylthiophene moieties are connected with head-to-tail (HT) and tail-to-tail (TT) orientations, were synthesized. HT bithienoquinonoid was isolated in a single form together with a small amount of its bromo derivative, similarly to the case for the head-to-head (HH) orientational isomer. On the other hand, TT isomer exhibited a peculiar feature in solution, affording an equilibrium mixture of two geometrical isomers. Electronic and electrochemical properties of these bithienoquinonoids were studied and compared with those of HH isomer. The results proved that all these bithienoquinonoid compounds possess highly polarizable and electron-acceptable properties. HH bithienoquinonoid was reduced through one two-electron transfer process, while HT and TT isomers were reduced through two one-electron transfer processes via stable radical anions to the corresponding dianions.

Effect of aryl substituents on intramolecular cyclizations of 3,3',5,5'-tetraaryl-2,2'-biphenoquinones (Ar = phenyl (la) and 4-methoxyphenyl (1b)) has been studied. In benzene, la gave 2,4,6,8-tetraphenyldibenzofuran-l-ol (10) gradually as a main product, indicating the phenyl substituents preferred to stabilize the intermediate by delocalization of the negative charge rather than that of the positive one. In contrast, the reaction of lb occurred spontaneously in order to give a complex mixture, which should be due to 4-methoxyphenyl substituent at the 3 position.

Reactivity of two isomeric quinone dimers, 5,5'-di-tert-butyl-2,2'-bisbenzoquinone (2) and 6,6'-di-tert-butyl-2,2'-bisbenzoquinone (3) have been compared. Both quinone dimers underwent thermal cyclization in ethanol to give dibenzofuran-1,4-diones exclusively, the reaction proceeding faster for 3 than for 2. Molecular modeling analysis indicates that the different reactivity should be explained in terms of the steric hindrance of tert-butyl group in 2, which prevents approaching of solvent molecules to C=O moiety so that the solvent-assisted proton transfer occurs more slowly.

The titled tetrathiacyclophane was prepared by improved synthetic methods and its molecular structure previously reported was corrected by 1H-NMR and X-ray analyses.

Metallocubanes are shown to be available by a transmetalation procedure in which amide-activated cubanes are treated with LiTMP and a metal chloride. They are excellent precursors for new subsituted cubanes.