Electronic structures of carbazole and indole and the solvent effects on the electronic spectra

The results of the experimental studies on the solvent effects upon the fluorescence and the absorption spectra of carbazole and indole are described, which makes it possible to estimate the difference of the electronic structures in the fluorescence state from those in the ground state.The electronic structures of the molecules are studied theoretically on the basis of the experimental results.

---

Zusammenfassung Die Beeinflussung der Absorptions- bzw. Fluoreszenzspektren von Carbazol und Indol durch Lösungsmitteleffekte wird untersucht. Aus den Ergebnissen werden Rückschlüsse auf die Elektronenstrukturen der Grund- und Fluoreszenzzustände gezogen. Eine auf den experimentellen Resultaten basierende theoretische Behandlung der Elektronenstrukturen schließt sich an.

---

Résumé Nous avons étudié les effects de solvant sur les spectres d'émission et d'absorption du carbazol et de l'indole. Les résultats permettent des conclusions sur la différence entre les structures électroniques des états excité et fondamental. Des calculs sur ces structures sont faits à l'aide des données expérimentales.

     

Properties of internal heat supply with carbon dioxide reforming of methane over a Ni/Al2O3 catalyst.

An addition of 6%-oxygen into a reactant of CH₄/CO₂(1/1) gave lower operating temperature of carbon dioxide reforming of methane by 130 K in obtaining 0.029 MPa of H₂, accompanied by a more endothermic atmosphere in the catalyst bed than in the absence of oxygen. This revised version was published online in June 2006 with corrections to the Cover Date.     

Capillary electrophoresis for simultaneous determination of emodin,chrysophanol, and their 8-beta-D-glucosides

The simultaneous separation and determination of the major anthraquinones, emodin, chrysophanol, and their glucosides, of Rumex japonicus HOUTT., and emodin and emodin glucoside, of Cassia tora L., Rhamnus purshiana DC., Polygonum multiflorum THUNB., and P. cuspidatum SIEB. et ZUCC., were achieved by cyclodextrin modified capillary zone electrophoresis. The running electrolyte used in this method was 0.005 M alpha-cyclodextrin in 0.03 M borate buffer (pH 10.5) containing 10% acetonitrile, with an applied voltage of 20 kV.     

An efficient synthesis of a class of novel N‐Alkyl‐N‐aryl‐4‐hydroxy‐1‐methyl‐2‐oxo‐1,2‐dihydro‐3‐quinolinecarbothioamides

The novel title compounds have been prepared in high yield by an optimized amide coupling followed by a Dieckmann cyclization. Additionally, this new route is amenable to preparative scale synthesis.     

Stereoregularity of polystyrene-β,β-d2

The 100-MHz methine proton spectra of polystyrene-β,β-d₂ obtained by radical and cationic initiators consisted of four peaks at 2.35, 2.25, 2.17, and 2.03 ppm, the proportion of which changed with polymerization conditions such as catalyst, solvent, and temperature. The spectrum was interpreted in terms of pentad sequences assuming Bernoullian statistics and the stereoregularity was determined. Polystyrene-β,β-d₂ prepared by radical initiators had a syndiotactic-rich configuration, independent of polymerization temperature. Polymers obtained by cationic initiators had lower racemic dyads. Cationic polymerization in toluene at 0°C gave a polymer of an almost random configuration. It was revealed that nondeuterated polystyrene of a random configuration can be distinguished from syndiotactic-rich polystyrene as well as the isotactic polymer by 100 MHz NMR spectroscopy.     

Carbazoledioxazines having long alkyl groups 1. Synthesis of carbazoledioxazines with linear type structure

Carbazoledioxazines with linear type structure (5,15-dialkyl-8,18-dichloro-5,15-dihydrodiindolo[3,2-b:-3′,2′-m]triphenodioxazine) were selectively synthesized by demethanolation ring closure of 2,5-bis(2-methoxy-9-alkyl-3-carbazolylamino)-3,6-dichloro-1,4-benzoquinone in a high boiling solvent. The structure has been confirmed by ¹H-nmr and X-ray crystallography.     

Fragment interaction analysis based on local MP2

We have developed a fragment interaction analysis based on local MP2 (FILM) in the context of the fragment molecular orbital (FMO) scheme. The primary purpose of this work is to provide a tool for analyzing inter-fragment interaction associated with dispersion interactions in a large molecule such as protein and DNA. Our implementation of local MP2 (LMP2) is based on the algorithm developed by Pulay and Werner. A potential of FILM was demonstrated using the human immunodeficiency virus type 1 protease (HIV-1 PR) complexed with lopinavir (LPV). The total energy, binding affinity, and inter-fragment interaction energy (IFIE) by the FMO method using LMP2 were compared with those obtained by canonical MP2 and the site-specific information in dispersion interaction was obtained. It turned out that the FILM is a useful tool for analyzing the dispersion interaction between an amino acid residue and a specific site of a ligand.     

Novel transformation of arenediazonium salts to acid anhydrides under palladium catalysis

Palladium catalyzed reaction of arenediazonium salts, carbon monoxide and sodium carboxylates gave mixed anhydrides, which in turn could be converted to aromatic acid anhydrides in good yields.     

External chiral ligand-mediated enantioselective Peterson reaction of alpha-trimethylsilanylacetate with substituted cyclohexanones

[reaction: see text] The asymmetric Peterson reaction of an alpha-trimethylsilanylacetate with 4-substituted and 3,5-disubstituted cyclohexanones was mediated by an external chiral tridentate ligand to give the corresponding olefins with an axial chirality in high yields and enantioselectivities of up to 85%.     

Monomer-isomerization polymerization. XVIII. Monomer-isomerization copolymerizations of 4-phenyl-2-butene with 4-methyl-2-pentene and 3-heptene with Ziegler-Natta catalyst

4-Phenyl-2-butene (4Ph2B) undergoes monomer-isomerization copolymerization with 4-methyl-2-pentene (4M2P) and 2-and 3-heptene (2H and 3H) with TiCl₃–(C₂H₅)₃Al catalyst at 80°C to produce copolymer consisting exclusively of 1-olefin units. For comparison the copolymerization of 4-phenyl-1-butene (4Ph1B) with 4-methyl-1-pentene (4M1P) and 1-heptene (1H) was carried out under similar conditions. The composition of the copolymers obtained from these copolymerizations was determined from the ratios of optical densities D₁₃₈₀ and D₁₆₀₀ of infrared (IR) spectra of their thin films. The apparent monomer reactivity ratios for the monomer-isomerization copolymerization of 4Ph2B with 4M2P, 2H, and 3H in which the concentration of olefin monomer in the feed was used as internal olefin and those for the copolymerization of 4Ph1B with 4M1P and 1H were determined as follows: 4Ph2B(M₁)-4M2P(M₂); r₁ = 0.90, r₂ = 0.20, 4Ph1B(M₁)-4M1P (M₂); r₁ = 0.40, r₂ = 0.70, 4Ph2B(M₁)-2H(M₂); r₁, = 0.45, r₂ = 1.85, 4Ph2B(M₁)-3H(M₂); r₁ = 0.50, r₂ = 1.20, 4Ph1B(M₁)-1H(M₂); r₁ = 0.55, r₂ = 0.75. The difference in monomer reactivity ratios seemed to originate from the rate of isomerization from 2- or 3-olefins to 1-oletins in these monomer-isomerization copolymerizations.