bluuebunny/crossref_metadata_2025 huggingface dataset:
Delayed Excimer Fluorescence of Acridine Orange Bound to DNA
Authors: Motoda Yuko , Kubota Yukio
Published: July 2006

The temperature dependence of long-lived emissions of Acridine Orange bound to DNA has been investigated. Only phosphorescence with a maximum close to 620 nm is observed in the range 77—ca. 150 K. With a rise in temperature, the delayed thermal fluorescence around 530 nm is observed in addition to phosphorescence at a high ratio of DNA phosphate to dye (P⁄D). With a decrease in P⁄D value, the delayed thermal fluorescence is replaced by a new delayed emission band around 640 nm. Its maximum wavelength is very close to that of dimer fluorescence of Acridine Orange in water. It has been shown that the emission results from two processes: (1) thermal excitation of the triplet state of the dimer to the excimer state and (2) excimer formation after the thermal excitation of the triplet state of the monomer to the first excited singlet state.
Preparation and Resolution of a Series of Chromium(III) Complexes Containing 2,2′-Bipyridyl N,N′-Dioxide and Ethylenediamine
Authors: Kanno Hideaki , Kashiwabara Kazuo , Fujita Junnosuke
Published: July 2006

A series of chromium(III) complexes of the type, [Cr(bpdo)n(en)3−n]3+ was obtained by preparing two new complexes, n=1 and 2, where bpdo denotes 2,2′-bipyridyl N,N′-dioxide. Each of the bpdo complexes gave only one pair of enantiomers, which were resolved by an SP-Sephadex column chromatographic or a chemical method. The circular dichroism spectra of the resolved complexes were compared with those of the related complexes of the known absolute configuration. The [Cr(bpdo)3]3+ complex in water racemizes spontaneously in dark. The rate is independent of the concentrations of the complex, acid, and the free ligand, and an intramolecular racemization mechanism is suggested.
The Acid-catalyzed Reaction of Alicyclic Ketones with Formaldehyde. III.The Reaction of 3- and 3,5-Methyl-substituted Cyclohexanones with Formaldehyde
Authors: Hirano Fukumi , Wakabayashi Shoji
Published: July 2006

The reaction of 3- and 3,5-methyl-substituted cyclohexanones with formaldehyde in acid media has been studied. The acid-catalyzed reaction gave 2,4,12,14-tetraoxatricyclo[8.4.0.01,6]tetradecane, 2,4-dioxaspiro[5.5]undecan-7-one, and 2,4,8,10-tetraoxatricyclo[4.4.4.01,6]tetradecane derivatives. The effect of the methyl groups on the product distribution has been discussed.
Photoisomerization and Photodimerization of 3-(1- and 2-Naphthyl)acrylate in Bichromophoric Systems
Authors: Tanaka Hideaki , Takamuku Setsuo , Sakurai Hiroshi
Published: July 2006

The photochemical trans-cis isomerization of methyl 3-(1- and 2-naphthyl)acrylate (1Me and 2Me) and the intramolecular (2+2) cycloaddition of ethylene bis[3-(1- and 2-naphthyl)acrylates] (1E and 2E) have been studied in cyclohexane and methanol. The quantum yield of the trans-cis isomerization of 2Me and 2E in methanol was larger than that in cyclohexane, while the yield of the cyclization of 2E showed the reverse. The isomerization is thought to occur via the triplet state, while the cyclization is via the singlet excited state. The triplet yield of 2Me in the polar solvent has been estimated to be larger than in nonpolar solvent. The cyclization of 1E was much slower than that of 2E, and the quantum yield of the reaction of 1Me and 1E did not appreciably depends on the polarity of the solvent.
Nitrogen Compounds in Petroleum. IV. Distribution Profiles of Nitrogen Compounds in Petroleum by Solid-Liquid Chromatography
Authors: Nomura Akira , Morita Yazaemon , Kogure Yukitoshi
Published: July 2006

A simple method for the characterization of nitrogen compounds in petroleum products by the investigation of the distribution profiles of nitrogen compounds using stepwise gradient elution on silica gel has been conducted. Samples were charged onto a 8φ×150 mm glass column containing 3 g of silica gel for column chromatography, followed by 15 ml of hexane to remove the non-polar bulk hydrocarbons from the sample. The eluate collected was removed from the solvent and analyzed for nitrogen, wt % yield and UV absorbance at 220 nm. The same procedure was followed by each 15 ml of 1, 3, 5, 10, 30, 60, 100%(v/v)-THF in hexane eluents. Plots of the nitrogen contents vs. the concentration of eluents gave characteristic patterns for petroleum distillates. The crude and residual oils from different geological sources exhibit similar nitrogen distribution profiles. There are two peak values; the peak at 3%-THF increases and that at 30%-THF decreases as the boiling range of the distillate decreases. Nitrogen compounds are distributed uniformly in a wide range of polar components with regard to adsorptivity on silica gel. The method was further applied to the reaction products of quinoline and indole by irradiation with UV light in isooctane (2,2,4-trimethylpentane) solution.
Electrochemical Synthesis and Reactivity of α-Alkoxy α-Amino Acid Derivatives
Authors: Iwasaki Tameo , Horikawa Hiroshi , Matsumoto Kazuo , Miyoshi Muneji
Published: July 2006

α-Alkoxy α-amino acid derivatives were synthesized in good yields by anodic oxidation of acylaminomalonic acid monoesters in alcohols. Transformation of ethyl N-acetyl-α-methoxyalaninate into ethyl N-acetyl-α,βdehydroalaninate was achieved in an excellent yield by thermal treatment of the former amino acid with a catalytic amount of ammonium bromide. Substitution of the α-alkoxy group of the α-alkoxy amino acids with nucleophiles was effected by tin tetrachloride to afford the α-substituted α-amino acids.
Preparation of S-Vinylsulfilimines
Authors: Yamamoto Tamotsu , Kakimoto Masa-aki , Okawara Makoto
Published: July 2006

For the preparation of S-vinylsulfilimines (1), mainly S-phenyl-N-tosyl-S-vinylsulfilimine, three routes were examined, viz., (A) the reaction of vinyl sulfide with chloramine T, (B) that of 2-haloethyl phenyl sulfide with chloramine T followed by dehydrohalogenation, and (C) that of 2-hydroxyethyl sulfide with chloramine T followed by acetylation of the hydroxyl group and deacetoxylation. Route A has disadvantages of troublesome preparation of vinyl sulfides and low yield. Route B gives the precursor sulfilimine to 1 in good yield only by use of anhydrous chloramine T. Route C gives the best results in view of starting material and yield.
Synthesis and Properties of Bis(cyclopropylphenyl)cyclopropenones and the Tris(p-cyclopropylphenyl)cyclopropenium Ion
Authors: Komatsu Koichi , Tomioka Isao , Okamoto Kunio
Published: July 2006

The reaction of trichlorocyclopropenium tetrachloroaluminate with cyclopropylbenzene has been found to readily afford the disubstitution products, bis(p-cyclopropylphenyl)- (1a), (p-cyclopropylphenyl) (o-cyclopropylphenyl)-, and bis(o-cyclopropylphenyl)cyclopropenones, each of which has been separated and fully characterized spectroscopically. The tris(p-cyclopropylphenyl)cyclopropenium ion (2) could not be obtained by the direct trisubstitution of the trichlorocyclopropenium ion with cyclopropylbenzene, but has been synthesized via two other routes starting from cyclopropenone 1a. The UV and 13C NMR spectral data of the cation 2 indicated the conjugative interaction of the para-cyclopropyl group with the cyclopropenium ring. However, the cation-stabilizing effect of the para-cyclopropyl group, as shown by the pKR+ value (3.23 in 23% ethanol) for 2, is much smaller than in the case of the tris(p-cyclopropylphenyl)methyl cation. This has been interpreted in terms of the decrease in delocalization of the positive charge to the para-position of the cation 2, when compared with the triarylmethyl analogue.
Imidazopteridines. II. Synthesis of Imidazo[1,2-c]pteridines with a Functional Group at the 6-Position
Authors: Sugimoto Takashi , Shibata Keiko , Matsuura Sadao
Published: July 2006

Several imidazo[1,2-c]pteridines with a functional group such as amino, alkylamino, alkoxyl, or hydroxyl group at the 6-position were synthesized by a nucleophilic replacement of 6-methylthioimidazo[1,2-c]pteridine with an appropriate nucleophile. The key intermediate methylthio compound was synthesized by condensation of 4-amino-2-methylthiopteridine with chloroacetaldehyde. Similarly, 4-amino-6,7-dimethyl-2-methylthiopteridine and chloroacetaldehyde gave 2,3-dimethyl-6-methylthioimidazo[1,2-c]pteridine, which was also used as a precursor to synthesize several imidazopteridines analogous to above.
Polyelectrolyte Complexes of [2-(Diethylamino)ethyl]dextran Hydrochloride with Sodium Carboxymethylcellulose
Authors: Kikuchi Yasuo , Koda Takashi
Published: July 2006

Sodium carboxymethylcellulose(anti-thrombogenic material)(CMC) reacted with [2-(diethylamino)ethyl]dextran hydrochloride(anti-cancer material)(EA) having an opposite charge and three groups of different basicity at different hydrogen ion concentrations to form novel water-insoluble precipitates, the so-called polyelectrolyte complex(PEC) comprised of both biomedical materials, focusing on the coagulation of precipitate(PEC) produced. The mole ratio N(EA)/Na(CMC) of the reaction mixture in solution at the start coagulation increased with a lowering of hydrogen ion concentration. This depended on the change of the degree of dissociation of EA and CMC with changing hydrogen ion concentration. The nitrogen contents which describe the mole ratios of EA/CMC in each PEC thus prepared were determined to range from 1.75 to 4.51. It was established that the hydrogen ion concentration and mixing mole ratio of N/Na in solution play an important role in determining the composition ratio of EA/CMC in the PEC. The results of IR, elemental analyses, solubility measurements, degree of swelling in water, color reaction with Toluidine Blue, and blood clotting test for PEC, revealed that the molecular structure of the various PEC’s differed according to the hydrogen ion concentration and the mole ratio of reaction mixture in solution, though all PEC’s were prepared from the same starting materials. It appears that the degree of dissociation and conformation of EA and CMC change with hydrogen ion concentration. The blood clotting tests were performed on a slightly swelled tablet of PEC where it was found that the PEC suppressed coagulation of the blood.
Photoinduced Dechlorination of β-Benzene Hexachloride in Alkaline Alcohols
Authors: Ogata Yoshiro , Takagi Katsuhiko , Sasoh Yasuharu
Published: July 2006

Photo-induced dechlorination of β-benzene hexachloride(β-BHC) in alkaline alcohols has been studied. Benzene is a major product accompanying other minor products such as chlorobenzene, alkoxybenzene, and benzyl alcohols. Their yields vary a great deal depending on the kind of alcohol. The efficiency of reaction and the selectivity of benzene increase in the order : methanol<ethanol<2-propanol. The reaction may go by way of dechlorination of β-BHC with base in the dark giving trichlorobenzenes(predominantly 1,2,4-isomer) followed by its photochemical dechlorination. The radical chain mechanism involving H-abstraction by Cl· atom is presented, since the efficiency is raised ca. 8 times as much as that in the dark.
On the Effects of Crystalline Planes and Purities on Working States of Vanadium Oxide Catalysts in CO-oxidation
Authors: Kera Yoshiya
Published: July 2006

It was confirmed that the kinetics of CO-oxidation over powdered V2O5 under the condition of (PCO⁄PO2) more than 2 differed clearly from that under the (PCO⁄PO2) less than 2 at 450 °C. The activation energies were 5.6 kcal/mol at 250–410 °C and 13 kcal/mol at 410–490 °C under a reductive condition of (PCO⁄PO2)=4.4, and on the other hand 5.9 kcal/mol at 250–490 °C under an oxidative condition of (PCO⁄PO2)=0.43. On a thin crystalline sample, in which the (010) plane was exposed extensively to the surface, a very rapid process appeared at the initial stage but was soon followed by a steady process. The rapid process was explained well by the Elovich law. On the thin crystalline, cautiously purified, the Elovich process did not appear, but the initial rapid process was kept steadily for 10–20 min and then followed by the other steady process. Accompanied by the change in the kinetics during the reaction, the activation energy changed from 2.3 kcal/mol at 271–410 °C and 17 kcal/mol at 410–480 °C to 29 kcal/mol at 271–480 °C under the (PCO⁄PO2)=2.1. Based on these results, the effects of the crystalline planes and the purities on the working states of V2O5 crystal in CO-oxidation are discussed.
Solubility Isotherms of Reciprocal Salt-Pairs of Optically Active Cobalt(III) Complexes
Authors: Fuyuhiro Akira , Yamanari Kazuaki , Shimura Yoichi
Published: July 2006

Two kinds of four-component solubility isotherms consisting of (Λ-[Co(ox)(en)2]+, Δ-[Co(ox)(en)2]+)–(Cl−, X−)–H2O, where X− stands for Δ-[Co(edta)]− or (R,R)-C4H5O6−, have been determined experimentally at 25 °C. It has been found that neither double salt nor solid solution exists and no configurational activity is observed in these systems. The applications of these phase diagrams to the practical optical resolutions are discussed.
Emission Spectra and Luminescence Life Times of Uranium–Mica Type Compounds
Authors: Sugitani Yoshinori , Kato Kenji , Nagashima Kozo
Published: July 2006

A series of uranium–mica type compounds M(UO2)2(XO4)2·nH2O, where M=Ca, Sr, Ba, Mg, Na2, K2, and (H3O)2; X=P and As, as well as the doped samples of Mg(UO2)2(PO4)2·nH2O : Mn(0.03 mol %) and Zn-(UO2)2(PO4)2·nH2O: Cu(0.1 mol %), have been prepared and measured for emission spectra under the UV(365 nm) excitation and decay times. Some of these samples, e.g., (H3O)2(UO2)2(AsO4)2·nH2O, have been found to give weak shoulders and a separated band, in addition to the six bands so far reported for other uranyl(VI) compounds. Samples containing AsO43− ions in place of PO43− gave emission spectra, where the main bands shifted by approximately 100 cm−1 to lower energy also giving shorter life times. The decay times of the six emission bands of Mg(UO2)2(PO4)2·nH2O have been found to have the same value of 2.5×10−4 s.
Chemistry of Organo Halogenic Molecules. XLVIII. Stereochemistry of Halofluorination of 1,2- and 1,4-Dihydronaphthalene
Authors: Stavber Stojan , Zupan Marko
Published: July 2006

Halofluorination of 1,2-dihydronaphthalene with a mixture of N-chlorosuccinimide or N-bromosuccinimide or N-iodosuccinimide–hydrogen fluoride–pyridine in ether proceeds with Markovnikov type regioselectivity. The reaction is stereospecifically anti, the anti adduct isomerizing to syn products under the reaction conditions. The elimination of hydrogen halide under basic conditions occurs only from the syn adduct, thus forming 1-fluoro-3,4-dihydronaphthalene. Halofluorinations of 1,4-dihydronaphthalene also occur stereospecifically anti, and elimination under basic conditions gives naphthalene.
Spirans. 16. 3,3′-Spirobi[3,4-dihydro-2H-[1,3]oxazino[3,2-a]benzimidazole] and Its Thia Analogue
Authors: Smoli\'{n}ski Stefan , Czarny Agnieszka
Published: July 2006

In order to obtain spiran the sodium derivative of o-phenylenediamine was subjected to reaction with 1,3-dibromo-2,2-bis(bromomethyl)propane in N,N-dimethylformamide. The compound was also synthesized by the reaction of the sodium derivative of 2,3-dihydro-1H-benzimidazol-2-one with 1,3-dibromo-2,2-bis(bromomethyl)propane. By this procedure the thia analogue of the spiran was obtained. In both cases the condensation route was unexpected. This is due to the fact that the solvent (DMF) takes part in the reaction and a stereo-electronic situation occurs, which is similar to that covered by Bredt’s exclusion rule.
Promoting Action of Inorganic Gases on the Rate of Dehydration of 2-Propanol over Ca-Y Zeolite
Authors: Ishinaga Yoshio , Otsuka Kiyoshi , Morikawa Akira
Published: July 2006

The dehydration of 2-propanol over Ca-Y zeolite has been enhanced in the presence of NO2, SO2, and Cl2 at 100 °C. This promoting action has been ascribed to the formation of acidic hydroxyl groups resulting from the reaction of the inorganic gases with zeolitic water or basic hydroxyl groups attached to the metal cations.
Solvent Isotope Effect of H2O and D2O on the Partition Coefficient of 1,3-Di-n-alkyl-1,3-propanedione
Authors: Watarai Hitoshi , Murakami Motoya , Suzuki Nobuo
Published: July 2006

The apparent partition coefficients of seven 1,3-di-n-alkyl-1,3-propanediones have been determined in dodecane/H2O and dodecane/D2O systems. From the results, the transfer free energies of β-diketones from H2O to D2O, ΔGH2O→D2O, have been calculated and are discussed in terms of the cavity formation energy.
Separation of Barium and Radium as Their TTA-complexes by Extraction Chromatography
Authors: Jin Kazuo , Kiba Toshiyasu
Published: July 2006

Satisfactory separation of a trace amount of radium from miligram amount of barium was attained on a column of 1.5 M TTA–MIBK (Daiflon) system. An HETP value as low as 0.47 mm was obtained with a column 0.98φ×30 cm at flow rate of 0.17 cm3 per minute. Distribution ratio of radium estimated from this column technique was compatible with the liquid-liquid extraction data.
Crystallographic Properties of Ca2Fe2O5. Difference in Crystallographic Properties of Brownmillerite-like Compounds, Ca2Fe2O5 and Sr2Fe2O5, at Elevated Temperatures
Authors: Shin Shigemitsu , Yonemura Michiko , Ikawa Hiroyuki
Published: July 2006

High-temperature X-ray diffraction analysis has revealed that Ca2Fe2O5 remains in the original brownmillerite-like form up to ca. 1100 °C, whereas Sr2Fe2O5 changes in crystal structure from brownmillerite to anion-deficient perovskite, without a change in oxygen content, above 700 °C.
Electrochemical Vicinal Addition of Two Alkyl Groups to Phenyl Substituted Olefins and Diethyl Fumarate
Authors: Satoh Sh\={o}hei , Taguchi T\={o}ru , Itoh Mitsuomi , Tokuda Masao
Published: July 2006

Electrochemical reactions of styrene, 1-phenyl-1-propene, 2-phenyl-1-propene, stilbene, and diethyl fumarate with alkyl halides in hexamethylphosphoric triamide containing lithium chloride produce the corresponding vicinal adducts of two alkyl groups of alkyl halides.
The Formation of the Oxidized Fe3O4–Fe2TiO4 Solid Solution by the Air Oxidation of the Aqueous Suspension
Authors: Katsura Takashi , Tamaura Yutaka , Chyo Gyong Sun
Published: July 2006

The oxidized Fe3O4–Fe2TiO4 solid solution with the spinel type structure was synthesized by means of ferrite methods at pH 9.0 and 65 °C. When the solid solution thus obtained was heated at 200 or 300 °C in air for 20 h, it was completely oxidized to form a ferromagnetic product, which retained the spinel type structure for Ti/Fetotal ratios from 0 to 0.5.
Intercalation Compounds FeOCl(Pyridine derivatives)1⁄n and FeOCl(n-Propylamine)1⁄4
Authors: Kikkawa Shinichi , Kanamaru Fumikazu , Koizumi Mitsue
Published: July 2006

Some pyridine derivatives were intercalated into the van der Waals gap of layered compound FeOCl. Pyridine, 2,6-dimethylpyridine, 4-aminopyridine, 2,4,6-trimethylpyridine, and n-propylamine were used as intercalates having different Lewis basicities. X-Ray diffraction, Mössbauer effect, electrical resistivity, ESR and electronic spectra were studied, some correlations being found between the measured parameters of these complexes and the basicities of organic intercalates. It is assumed that organic intercalates transfer their lone pair electrons on the nitrogen atom to FeOCl layers.
Electron Spin-Spin Interaction and Translational Diffusion of Nitroxide Radicals in Sodium Dodecyl Sulfate Micelles
Authors: Aizawa Masayuki , Komatsu Tsuyoshi , Nakagawa Tsurutaro
Published: July 2006

The line width measurements of ESR spectra of 2,2,6,6-tetramethyl-4-benzoyloxypiperidinyl-1-oxyl (BzONO) in sodium dodecyl sulfate (SDS) micelles have been carried out at various concentrations of BzONO. The plot of the line width against the concentration of BzONO shows a line with a break at mole fraction ca. 0.05, as opposed to the theoretical prediction that the plot would give a straight line. In order to explain this anomalous behavior, three models for the solubilization of BzONO are considered. On the basis of two of these models, spin exchange rates of BzONO in the micelles are estimated. Translational diffusion coefficients of BzONO in the SDS micelles at 20, 31, and 38.5 °C are calculated by using the spin exchange rate constants and an appropriate diffusion model. The obtained values are of the order of 10−7 cm2/s.
An UV-Visible Spectrophotometer Provided with a Photon Counting System for the Studies of Very Weak Absorption Spectra
Authors: Yamamoto Naoto , Sawada Takanori , Tsubomura Hiroshi
Published: July 2006

An ultrasensitive UV-visible spectrophotometer, of a single-beam type provided with a photon counting system having a time resolution of 10 ns has been constructed. It has been shown that absorption spectra can be measured to within an error of 10−5 in optical density with this instrument. Noise levels, measured as a function of the photon count numbers, are found to agree with the theoretically expected statistical fluctuation of the photons. Absorption spectra of thin naphthacene films, 32 nra or below in thicknesses, deposited on a quartz plate, were obtained with this instrument, and found to change with the film thickness.
Cyclopentenone Synthesis from 1,1-Dichloroallyllithium–Ketone Adducts as Well as from Dichlorocarbene–Allyl Alcohol Adducts
Authors: Hiyama Tamejiro , Shinoda Masaki , Tsukanaka Masao , Nozaki Hitosi
Published: July 2006

Treatment of (3,3-dialkyl-2,2-dichlorocyclopropyl)methanols with hydrobromic acid gives 2-cyclopentenones through postulated intermediates, 3-chlorocyclopentadienyl cations. Another method which should give the same cationic intermediates involves trifluoroacetic acid catalyzed reaction of 3,3-dichloro-1-alken-4-ols. This is found to be particularly useful for cyclopentenone annulation.
The Enantioface-differentiating (Asymmetric) Hydrogenation of the C=O Double Bond with Modified Raney Nickel. XXXIV. The Adsorption Mode of 2-Hydroxy Acid on Raney Nickel
Authors: Harada Tadao
Published: July 2006

The adsorbed species of the modifying reagent and the surface states of the catalyst caused by the modification of a Raney nickel with 2-hydroxy acid at various pH regions were investigated. The adsorption mode of 2-hydroxy acid was proposed in each modifying-pH region; that is, (1) in a pH region intrinsic to the solution of the free 2-hydroxy acid, nickel salt of 2-hydroxy acid was adsorbed on the catalyst surface corroded by the acid; (2) under weakly acidic conditions, nickel salt and sodium salt of 2-hydroxy acid were adsorbed on the catalyst surface partially corroded by the acid; (3) under neutral conditions, the sodium salt was adsorbed on the surface of the fresh Raney nickel, and (4) under strongly basic conditions, the sodium salt and NaOH were adsorbed on the surface of the fresh Raney nickel.
Liquid-phase Peptide Synthesis by Fragment Condensation on a Soluble Polymer Support. III. The Influence of the Content and the Chain Length of a Peptide Anchored to a Soluble Polymer Support on the Reactivity of the Amino-free Terminal of the Peptide
Authors: Narita Mitsuaki , Itsuno Shin-ichi , Hirata Masanori , Kusano Kazuya
Published: July 2006

In order to investigate the influence of the content and the chain length of a peptide anchored to a soluble polymer support on the reactivity of the amino-free terminal of the peptide, chloromethylated polystyrene, which is a starting material for peptide synthesis on a matrix, was prepared by the copolymerization of (chloromethyl)styrene with styrene. By the copolymerization, the chloromethyl content on the resin was easily controlled and obtained as reproducible. The repetitive peptide-chain elongations of a pentapeptide, –(Ala2–Leu3)–, and a decapeptide, –(Ala2–Leu3–Pro2–Leu3)–, were performed by the usual method, using soluble polymer supports with various contents of Ile–Ile, which was used as the internal reference to evaluate the coupling yields by means of amino-acid analyses of the resulting peptide resins. The solubility of the peptide resin, which depends on the content of the peptide and the solubility of the peptide fragment on the matrix, was found to be one of the important factors for an efficient coupling in liquid-phase fragment condensations on a soluble polymer support.
The Total Synthesis of Hydroxyisochamaecynone and Its Stereochemical Assignment
Authors: Ando Masayoshi , Asao Toyonobu , Takase Kahei
Published: July 2006

The structure of an acetylenic nor-sesquiterpene, hydroxyisochamaecynone, was determined to be 4α-hydroxy-5βH-13-noreudesm-1-en-11-yn-3-one (Ib) by means of the stereoselective total syntheses of two possible stereoisomers, Ib and 4β-hydroxy-5βH-13-noreudesm-1-en-11-yn-3-one.
Direct Conversion of Arylamines to the Halides by Deamination with Thionitrite or Related Compounds and Anhydrous Copper(II) Halides
Authors: Oae Shigeru , Shinhama K\={o}ichi , Kim Yong Hae
Published: July 2006

Reactions of various arylamines with either t-butyl thionitrite, t-butyl thionitrate, or p-toluenesulfonyl nitrite in the presence of anhydrous copper(II) halides under mild conditions gave corresponding aryl halides in good yields. This reaction in the presence of such olefins as acrylonitrile, styrene, and acrylic acid gave the corresponding 2-aryl-1-haloethanes as the main products. t-Butyl thionitrite, t-butyl thionitrate, and p-toluenesulfonyl nitrite were found to be better deaminative reagents than alkyl nitrites or alkyl nitrates due to their weak sulfur–nitrogen bonds.
Potentiometric Determination of the Concentration of Aggressive Anions That Can Be Tolerated by a Certain Passivator
Authors: Abd El Haleem Salah Mohamed , Abd El Aal Ali
Published: July 2006

The effect of various additives of Cl−, Br−, and I− on the potential of a passivated steel electrode was established. In solutions of Na2CrO4, Na2HPO4, and Na2WO4, S-shaped relations were obtained between the steady-state potential and the quantity of the aggressive salt added. The resulting active potentials were established after an induction period which decreases with increase in the concentration of the attacking ions and/or decrease in that of the inhibiting anions. The concentration, Cagg, that can be tolerated by a certain concentration of the inhibiting anion, Cinh, is given by logCinh=K+nlogCagg, where K and n are constants. The equation was derived theoretically on the basis of the changes produced in the structure of the double layer caused by specific adsorption of both aggressive and passivating ions. In solutions of KMnO4, NaNO2, and K3[(Fe(CN)6)], the passivating film could not withstand the corroding action of the halide ions.
Reactions of Imidoyl-palladium(II) Complexes with Electrophiles
Authors: Hiraki Katsuma , Fuchita Yoshio , Masumoto Toyohiko
Published: July 2006

Imidoyl-palladium(II) complexes, derived from the reactions between imidoyl chlorides and tetrakis(triphenylphosphine)palladium(0), react with perchloric acid or triethyloxonium tetrafluoroborate to give new aminocarbene-palladium(II) complexes.
Effect of Hydrogen Chloride on the Pyrolysis of Acetylene as Studied with a Single-pulse Shock Tube
Authors: Ogura Hiroo
Published: July 2006

The pyrolysis of acetylene in the presence of hydrogen chloride was investigated with a single-pulse shock tube in the temperature range 1100–1680 K. The hydrocarbons produced in the C2H2–HCl system were quite the same as those obtained in the C2H2–Ar system. The formation rate of the main pyrolysis product, 1-buten-3-yne, was reduced remarkably by the addition of hydrogen chloride, being of third-order and of inverse first-order with respect to the concentrations of acetylene and hydrogen chloride, respectively. The overall second-order rate constant obtained was

k(cm^3 mol^-1 s^-1)=2.9×10^12exp (-45800/RT).

As the chlorine atom containing product, only chloroacetylene was found in small amounts, its formation rate being of second-order with respect to acetylene. The inhibitory effect of hydrogen chloride on the 1-buten-3-yne formation rate was interpreted in terms of the change in the termination from the recombination reaction of 2-ethynylvinyl radical to the reaction of 2-ethynylvinyl radical with hydrogen chloride.
Field Theoretical Treatment of the Proton hfs in Aromatic Ion Radicals
Authors: Aono Shigeyuki , Nishikawa Kiyoshi , Deguchi Kisaburo
Published: July 2006

Field theoretical method to estimate the proton hfs in aromatic ion radicals is presented, and applied to explain why the proton hfs of the positive ion is larger than that of the negative ion of the same molecule. Since the Hartree-Fock orbitals of the neutral molecule are adequate for describing the negative ion state of this molecule, but not for the positive ion state, the correlation effect in the latter should be effectively taken into account, so that the particle propagators in the positive ion are renormalized. The hyperfine energy consists of two terms, the hyperfine self-energy term and the pole strength which is interpreted as the existence probability of the state under investigation. The electron correlation affects these differently between positive and negative ions.
The Preparation of Mesoporous Silica Gel and the Nature of the Modification of Its Surface with Organoalkoxysilane
Authors: Tanaka Kazuo , Shinoda Sumio , Takai Nobuharu , Takahashi Hiroshi , Saito Yasukazu
Published: July 2006

Mesoporous silica gel with a narrow pore-size distribution at the pore diameter of 200 Å has been prepared upon gelation in the presence of starch. Taking into account the effects on the geometrical properties of its surface, two typical surface-modifying procedures that utilize organoalkoxysilane were characterized. Procedure I retains the mesoporous structure, although the fixed amount of the organofunctional group is rather small. Procedure II introduces a large amount of the organofunctional group to the surface, but is accompanied by a pronounced reduction in both the B.E.T. surface area and the specific pore volume. The observed range of the apparent surface concentration of the organofunctional group and the scanning electron micrographs suggest that the surface is coated with highly crosslinked organosiloxane polymers in the latter case. Despite the contrasts between the two modified surfaces, the similarity of C-13 NMR line shapes, chemical shifts, and spin-lattice relaxation times between the respective surface organofunctional groups indicates that their microenvironment and mobility resemble each other.
Effect of a Polar Solvent on the 1JCH Spin-coupling Constants in Chlorine-substituted Ethanes
Authors: Watanabe Shosuke , Ando Isao
Published: July 2006

The directly-bonded 13C–H spin-coupling constants (1JCH) for two chlorine-substituted ethanes, CHCl2CHCl2 and CHCl2CH2Cl, have been measured in various solvents with a wide range of dielectric constants and/or as a function of the temperature. Also, these two effects were estimated by the finite perturbation theory based on the CNDO/2 approximation with the solvaton theory. Both experimentally and theoretically, the dielectric constant of a solvent affects the 1JCH more than the temperature. It is shown that the solvent effect on the 1JCH spin couplings in CHCl2CHCl2 and CHCl2CH2Cl arises mainly from electronic changes in the solute molecules caused by intermolecular solute-solvent interaction, more than from the change in the population of the rotational isomers.
Polymer-protected Colloidal Nickel Boride in Ethanol and Its Catalytic Activity for Hydrogenation
Authors: Nakao Yukimichi , Fujishige Shoei
Published: July 2006

Colloidal nickel borides were prepared in ethanol from nickel(II) chloride and sodium borohydride using a polymer as a protective colloid. For atmospheric hydrogenation of olefins such as acrylamide at 30 °C, the colloid prepared by using poly(vinylpyrrolidone) exhibited catalytic activity 15–60 times that of the usual nickel boride prepared without using a polymer. The high activity of colloidal nickel borides was found to be due to the polymers, soluble nylon being the most effective. The colloids are stable under oxygen-free hydrogen, decomposing immediately on exposure to air.
The Oxidation Reaction of Tl(I) to Tl(III) by the Peroxodisulfate Ion. I. Kinetics and Mechanism in an Aqueous Solution
Authors: Kimura Masaru , Akazome Tsuneko , Takenaka Kayo , Kobayashi Akiko
Published: July 2006

The oxidation reaction of the thallium(I) ion to the thallium(III) ion by the peroxodisulfate ion has been studied in an aqueous acidic solution. The reaction constituted a chain reaction initiated by the thermal decomposition of the peroxodisulfate ion, the reaction involving no direct reactions between the thallium(I) and peroxodisulfate ions. At thallium(I) ion concentrations larger than 0.004 mol dm−3, the reaction mechanism was assumed to be: S2O82−\oversetk1→2SO4\ewdot; S2O82−+H+\oversetk2→HSO4−+1/2O2+SO3; Tl(I)+SO4\ewdot\oversetk3→Tl(II)+SO42−; S2O82−+Tl(II)\oversetk4→Tl(III)+SO4\ewdot+SO42−; 2Tl(II)\oversetk5\undersetk−5\ightleftharpoonsTl(I)+Tl(III). The rate of the reaction was described as −d[S2O82−]/dt=(k1+k2[H+])[S2O82−]+k4(k1⁄k5)1⁄2[S2O82−]3⁄2. The rate constants at an ionic strength of 0.16 mol dm−3 were determined to be k1=1.99×1019exp[−157 kJ mol−1/RT]s−1, k2=2.75×1012exp[−103 kJ mol−1/RT] dm3 mol−1 s−1, and k4(k1⁄k5)1⁄2=2.81×1013exp[−108 kJ mol−1/RT] dm3⁄2 mol−1⁄2 s−1 in 0.01 mol dm−3 perchloric acid, the k4 value being increased with a decrease in the hydrogen-ion concentration. The ionic strength (μ) dependence was described as logk4(k1⁄k5)1⁄2=−4.17–1.05 μ1⁄2 in 0.01 mol dm−3 perchloric acid at 40 °C. The reaction rate was completely retarded by the addition of 1% acrlyronitrile, 5×10−6 mol dm−3 cerium(III) sulfate, 1×10−3 mol dm−3 cerium(IV) sulfate, or 0.1 mol dm−3 sodium acetate, and it was also remarkably retarded by the addition of 1×10−3 mol dm−3 tetranitromethane. The copper(II) ion and molecular oxygen did not appreciably affect the reaction rate, but the iron (III) ion accelerated it greatly.
Mössbauer Studies of the Gamma-ray-irradiation Effects of 1,10-Phenanthroline Compounds
Authors: Maeda Yonezo , Ohshio Hiroki , Takashima Yoshimasa
Published: July 2006

Mössbauer and infrared spectroscopies have been applied to the study of the gamma-ray-irradiation effects on eleven iron 1,10-phenanthroline compounds: [Fe(phen)2X2] (X=Cl−, HCOO−, NCO−, 1⁄2Ox2−, 1⁄2Mal2−, CN−, and NO2−), [Fe(phen)3]X2·nH2O (X=Cl−, ClO4−, HCOO−, and NO2−), [Fe(phns)2](ClO4)2·2H2O and [Fe(phnc)2](ClO4)2·H2O (phen=1,10-phenanthroline, phns=1,10-phenantroline-2-carbothioamide, and phnc=1,10-phenantroline-2-carboxamide). For all the low-spin complexes except [Fe(phen)3] (HCOO)2·6H2O, no chemical changes were observed on the Mossbauer spectra after irradiation. All the iron(II) complexes in the high-spin state except [Fe(phen)2Cl2] and [Fe(phnc)2] (ClO4)2·H2O were, however, changed to iron(III) species under the influence of irradiation. Three iron(II) complexes in the intermediate-spin state were sensitive to gamma-rays.
An X-Ray Photoelectron Spectroscopic Study of Several Ligands in Coordination Compounds
Authors: Yoshida Tooru
Published: July 2006

The N(1s) electron binding energies were measured by means of X-ray photoelectron spectroscopy for the complexes of 2-pyridinecarboxylic acid, 8-quinolinol, and anthranilic acid with a variety of bivalent metal ions. The correlations of their binding energies with the electronegativity and the ionic potential (Z⁄r) of the metal ion and the charge on the nitrogen atom, and the covalent character of the nitrogen–metal bond calculated on the basis of Pauling’s concept were examined. The chemical shift in the N(1 s) binding energy was about 1 eV at most. However, it was suggested that it is possible to use the chemical shift to determine the nature and strength of the nitrogen–metal bond in a series of complexes of the same ligand.
The Thermal Gas-phase Decomposition of Methyl Iodide
Authors: Saito Ko , Tahara Hiroyuki , Kondo Osamu , Yokubo Teiji , Thigashihara Tetsuo , Murakami Ichiro
Published: July 2006

The thermal gas-phase decomposition of methyl iodide diluted in Ar has been studied behind shock waves over the temperature range between 1050 and 1500 K and the total density range of 3.5×10−6–3.9×10−5 mol cm−3. The decomposition was monitored by means of the UV absorption of CH3I at 259 or 275 nm. The initiation reaction was found to be the C–I bond fission, and the process proceeded in the low-pressure region under the present experimental conditions. The low-pressure limit rate constant was obtained as:

k_2nd=10^15.40±0.26exp{-(42.56±1.50 kcal mol^-1)/RT}cm^3 mol^-1s^-1.

Applying the RRKM strong collision theory, the collision efficiency factor was estimated to be 0.018 at 1300 K.
Studies on 2-Aziridinecarboxylic Acid. IV. Total Synthesis of Actinomycin D (C1) via Ring-opening Reaction of Aziridine
Authors: Tanaka Takumi , Nakajima Kiichiro , Okawa Kenji
Published: July 2006

Actinomycin D (C1) has been synthesized by a route involving the ester formation between two peptide fragments, (2S,3S)-1-(2-nitro-3-benzyloxy-4-methylbenzoyl)-3-methyl-2-aziridinecarbonyl-d-valylproline t-butyl ester and N-benzyloxycarbonylsarcosyl-N-methylvaline, via a ring-opening reaction of aziridine. Cyclization, followed by reduction and oxidation, gave actinomycin D (C1). The synthetic actinomycin D (C1) was indistinguishable from natural substance as regards physical properties and biological activity.
Synthesis of Methyl 2,6-Di-N-acetyl-2,3,4,6,7-pentadeoxy-l-lyxo-heptopyranoside, a Derivative of 6-epi-d-Purpurosamine B
Authors: Suami Tetsuo , Honda Yutaka , Kato Tsuguhiro , Masu Mikio , Matsuzawa Kinya
Published: July 2006

6-epi-d-Purpurosamine B, 2,6-diamino-2,3,4,6,7-pentadeoxy-l-lyxo-heptopyranose, was found to be a component of antibiotic fortimicins. Methyl 2,6-di-N-acetyl-6-epi-α-d-purpurosaminide B has been synthesized from methyl 2-acetamido-2-deoxy-6-O-trityl-α-d-glucopyranoside.
The Structure of Nitronitrosoaconitinic Acid, the Oxidation Product of Aconitine with Nitric Acid
Authors: Amiya Takashi , Kanaiwa Yoshio , Bando Hideo , Nakano Naomi , Mori Takao , Suginome Harusada
Published: July 2006

The structure of nitronitrosoaconitinic acid, which is an oxidation product of aconitine with nitric acid, was confirmed by spectroscopic methods. This compound is a new type of acid, a 2-nitro-2-cyclohexen-1-one, with a pKa value comparable to that of carboxylic acids.
Kinetic Studies on the Decomposition of the Most Typical Meisenheimer Complex of Sodium 1,1-Dimethoxy-2,4,6-trinitrocyclohexadienide in Methanol
Authors: Abe Takehiro
Published: July 2006

The whole decomposition of the Meisenheimer complex formed from 2,4,6-trinitroanisole (TNA) and sodium methoxide proceeds in three steps and obeys the first-order kinetics in each step. The rate of the whole decrease of concentration of the complex is given by −d([TNA·CH3ONa]+[TNA·CH3O−])/dt=(k1[H+]+k2[CH3OH])×[TNA·CH3ONa]+(k3[H+]+k4[CH3OH])×[TNA·CH3O−]−k5[CH3O−]×[TNA], where k denotes a rate constant. This leads to the modification of the conventional unimolecular mechanism shown by TNA·CH3O−→TNA+CH3O−.
Oxidation of Methyl (Methylthio)methyl Sulfoxide
Authors: Ogura Katsuyuki , Suzuki Michiyo , Tsuchihashi Gen-ichi
Published: July 2006

Oxidation of methyl (methylthio)methyl sulfoxide (2) with hydrogen peroxide in acetic acid or methanol produced bis(methylsulfinyl)methane in high yield. Similar results were obtained in oxidation of 2 with ozone, sodium metaperiodate, and m-chloroperbenzoic acid. In contrast, methyl (methylthio)methyl sulfone (4) was exclusively formed when oxidation of 2 with hydrogen peroxide was carried out in methanol in the presence of sodium hydroxide. Furthermore, we established a convenient and efficient method of preparing 4 by oxidation of 2 with potassium permanganate.
Photochemical Type I and II Elimination Reactions of Dialkyl (Trichloromethyl)phosphonates
Authors: Suzuki Nobutaka , Kawai Teruyuki , Inoue Susumu , Sano Naoki , Izawa Yasuji
Published: July 2006

Irradiation of diisobutyl, dipropyl, and diethyl (trichloromethyl)phosphonates in MeCN gave corresponding monoesters and olefins via photochemical type II elimination. In addition, products via type I elimination were obtained from diisobutyl (trichloromethyl)phosphonate and its dimethyl ester.
On the Thermal Decomposition of Shock-heated SO2
Authors: Saito Ko , Yokubo Teiji , Higashihara Tetsuo , Murakami Ichiro
Published: July 2006

The SO2 pyrolysis was measured behind reflected shock waves under low SO2 concentrations. A typical induction zone was observed in the decomposition process. It was found that the overall rate constants after the induction zone were in good agreement with the values for the primary reaction obtained by the following investigators: Just and Rimpel, Kiefer, and Grillo et al. This implies that, even in highly diluted mixtures at low pressures, the kinetics of the SO2 decomposition is complicated.
Nitrogen 14 Nuclear Qnadrupole Resonance of Alloxan·H2O
Authors: Maruizumi Takuya , Hiyama Yukio , Niki Eiji
Published: July 2006

The 14N nuclear quadrupole resonance spectra of alloxan·H2O have been observed at room temperature. The predominant tautomer in a solid is concluded to be 5,5-dihydroxypyrimidine-2,4,6-trione. The NQR data were interpreted qualitatively by means of the Townes and Dailey theory.
Ground-state Energy Stabilization in Solid Cation Radical Salts Derived from Some Aromatic Hydrocarbons
Authors: Iida Yôichi
Published: July 2006

The ground-state energy stabilization due to the charge-transfer interaction between cation radicals was examined with solid cation radical salts of 9,10-dimethylanthracene, 9,10-dichloroanthracene, and perylene with antimony pentachloride and perchlorate anions.
An X-Ray Photoelectron Spectroscopic Study of Several Metal Complexes of 2-Mercaptobenzimidazole and 2-Mercaptobenzoxazole
Authors: Yoshida Tooru
Published: July 2006

The X-ray photoelectron spectra of several metal complexes of 2-mercaptobenzimidazole and 2-mercaptobenzoxazole were measured in order to examine the mode of coordination of the ligands. From their N(1s) and S(2p3⁄2) chemical shifts, it was suggested that the ligands are coordinated through both the sulfur and nitrogen atoms in most of the complexes.
The Liquid-Liquid Extraction of Zinc with Polyethylene Glycol and Poly(oxyethylene)-type Nonionic Surfactants
Authors: Suzuki Toshio , Murakami Naoyuki , Sotobayashi Takeshi
Published: July 2006

The Zn(II) extraction was made from its acidic thiocyanate solution, using polyethylene glycol and its mono(alkylphenyl) ether as extractants. The effects of the number of oxyethylene groups (–O–CH2–CH2–) per molecule and of the kind of the counter cation of thiocyanate on the extractability are described, together with some other factors affecting the Zn(II) extraction.
Solid State Reactions between Rare Earth Orthophosphate and Oxide
Authors: Hikichi Yasuo , Hukuo Ken-iti , Shiokawa Jiro
Published: July 2006

Solid state reactions between rare earth orthophosphate (RPO4) and oxides (SiO2, Al2O3, or CaO) in the air were studied by means of X-ray diffractometry. RPO4 does not react with SiO2, decomposing on heating above 1800 °C with Al2O3, or above 700 °C with CaO.
The Chemistry of 1,3-Glycol Derivatives. III. The Preparation of 1,1-Bis(1-hydroxyalkyl)cyclopropanes and Their Halogenation
Authors: Itoh Osamu , Kohmura Yoshiro , Ichikawa Yasunori , Umezu Makoto , Okita Tsutomu , Ichikawa Katsuhiko
Published: July 2006

By the reduction of 1,1-diacylcyclopropanes and their related compounds, several kinds of 1,1-bis(1-hydroxyalkyl)cyclopropanes have been prepared. Some of the stereoisomers were separated, and their configurations were determined by the NMR study of the 1,3-dioxanes prepared by the acetallization of the diols. The diols were subjected to halogenation. Although the reactions of meso- and dl-bis(1-hydroxyethyl)cyclopropanes with thionyl chloride and phosphorus pentachloride gave normal dichlorides, accompanied by slight skeletal rearrangements, the stereospecificities were rather low. With ZnCl2–HCl, the specificities were lost completely and large amounts of the homoallyl derivative were formed. The reaction mechanism is discussed.
The Reactions of Copper(I) 1-Alkenyltrimethylborates with Allylic Bromides or 2-Propynyl Bromide
Authors: Miyaura Norio , Yano Takashi , Suzuki Akira
Published: July 2006

The reactions between copper(I) 1-alkenyltrimethylborates (readily obtainable from 2-(1-alkenyl)-1,3,2-benzodioxaboroles and methyllithium) and allylic bromides or 2-propynyl bromide were found to give corresponding coupling products. These reactions provide new synthetic routes to 1,4-alkadienes or 1,2,7-alkatrien-5-ynes.
The Removal of Arsenate in Waste Water with an Adsorbent Prepared by Binding Hydrous Iron(III) Oxide with Polyacrylamide
Authors: Shigetomi Yasumasa , Hori Y\={o}ichi , Kojima Takehiro
Published: July 2006

Studies have been made to remove arsenate in waste water with an adsorbent prepared by binding hydrous iron(III) oxide with polyacrylamide. Arsenate anions were thus adsorbed over the pH range of 5–8; the adsorption capacity of arsenate was 43 mg per gram of the adsorbent.
The Dissociation Rate of S2 Produced from COS Pyrolysis
Authors: Higashihara Tetsuo , Saito Ko , Murakami Ichiro
Published: July 2006

The disappearance rate of S2, which was produced from the pyrolysis of COS, was measured behind incident shock waves by monitoring the UV emission in the temperature range of 4500–6000 K and in the pressure range of 0.32–0.5 atm. It was found that two processes could possibly account for the disappearance of S2:

S_2+Ar→2S+Ar\ ag3

and

(Remark: Graphics omitted.)

and the following rate equation was obtained:

-d[S_2]/dt=k_II[S_2][Ar]mol cm^-3s^-1

where

k_II=10^13.68exp(-77kcal/RT)cm^3mol^-1s^-1.
Structural Studies of Fortimicins. II. Crystal and Molecular Structure of Fortamine
Authors: Hirayama Noriaki , Shirahata Kunikatsu , Ohashi Yuji , Sasada Yoshio
Published: July 2006

Fortamine, l-3-amino-1-methoxy-6-methylamino-1,3,6-trideoxy-chiro-inositol, is a component of fortimicins which are potent aminocyclitol antibiotics. The space group is P21 with a=9.454(1), b=6.6957(8), c=7.622(1) Å, β=95.93(2)°, and two C8H18N2O4’s per unit cell. The structure was solved by direct methods, least-squares refinement using 932 reflexions giving the final R value of 0.033. The ring conformation of fortamine is closer to the ideal chair form than that of the fortamine moiety in fortimicin B. The strain caused by the intramolecular hydrogen bond and glycosidic bond in fortimicin B is released in fortamine.
Dissociation of μ-Oxo-bis[oxobis(8-quinolinolato)vanadium(V)] and μ-Oxo-bis[oxobis(4-isopropyltropolonato)vanadium(V)] in Chlorobenzene
Authors: Yuchi Akio , Muranaka Hiroshi , Yamada Shinkichi , Tanaka Motoharu
Published: July 2006

Dissociation of dimeric vanadium(V) complexes with 8-quinolinol(Hox) and 4-isopropyltropolone(Hipt), V2O3(ox)4 and V2O3(ipt)4, in organic solvents was studied spectrophotometrically. The equilibrium is found to be

V_2O_3L_4+H_2O\ightleftarrows2VO_2L+2HL

with the following logarithmic equilibrium constants: logK=−12.9 for L=ox− and −12.8 for L=ipt− in chlorobenzene. VO2L was synthesized and characterized by IR, UV, and visible spectroscopy for these ligands and also for 2-methyl-8-quinolinol.
Equilibrium, X-Ray, and 1H-NMR Studies of the ZrCr2–H System
Authors: Imoto Hideo , Sasaki Motoshige , Saito Taro , Sasaki Yukiyoshi
Published: July 2006

The pressure isotherms of the ZrCr2–H system (20–200 °C, 10–700 Torr) and powder X-ray diffraction have shown the occurrence of two phases, cubic ZrCr2Hx (x<1.0) and hexagonal ZrCr2Hx (2.5<x<3.5). From the gradual change in the diffraction pattern with x, it has been concluded that samples with a low hydrogen concentration (x<0.8) contain another hexagonal phase. All these phases have Laves-type structures (C14 and C15). At 106 K, ZrCr2H2.66 has a much smaller second moment (7.2 G) of 1H-NMR than the value calculated from the random-distribution model (77.9 G), which shows that the nearest sites can not be filled by hydrogen atoms at the same time. The system of TiCr2–H has also been studied for comparison.