bluuebunny/crossref_metadata_2025 huggingface dataset:
Photochemistry of Cobalt(III) Complexes. II. Cobalt(III) Complex with a Co–C–S Three-Membered Ring Prepared by Photodecarboxylation of 2,2′-Thiodiacetato Complex. Crystal Structure of (−)537CD-fac-trans(NH,O)-[Co(CH2SCH2COO)(dien)]ClO4
Authors: Yonemura Toshiaki , Kawaguchi Hiroshi , Shibuya Kimi , Murakami Kaori , Ama Tomoharu , Yasui Takaji , Okamoto Ken-ichi , Hidaka Jinsai
Published: July 2006

The diethylenetriamine (dien) cobalt(III) complex with a three-membered ring, fac-trans(NH, O)-[Co(CH2SCH2COO)(dien)]+ (1), has been prepared in an aqueous solution by the photodecarboxylation of u-fac- (2) or s-fac-[Co(2,2′-thiodiacetato)(dien)]+ (3). Perchlorate salt of 1 was subject to spontaneous resolution, and the crystal structure and absolute configuration for the isomer were determined by X-ray diffraction. The crystal is monoclinic, space group P21, a = 6.962(1), b = 13.411(1), c = 7.663(1) Å, β = 101.921(8)°, V = 700.1(2) Å3, Z = 2, and R = 0.032. The formation of the three-membered ring introduces a significant distortion into the octahedral coordination around the Co atom (∠C–Co–S = 49.4(1)°), although the bond lengths in the ring are within the range normally observed for other complexes. For the isomer the chiral configuration is regulated to ΔΛΔ and R for the sulfur atom. The racemization rate of 1 is very fast in water and DMSO. The position of the first d–d band of 1 is red-shifted by 1600—1100 cm−1 relative to those of 2 and 3. The photolysis of mer-[Co(3,3′-thiodipropionato)(dien)]+ did not give a similar product to 1.
Skeletal Rearrangement of the Dehydroabietic Acid Derivative
Authors: Matsumoto Takashi , Takeda Yoshio , Soh Kimiko , Sakamoto Mitsuo , Imai Sachihiko
Published: July 2006

Methyl 7-oxo-5,8,11,13-abietatetraen-18-oate was reduced with sodium borohydride in the presence of cerium(III) chloride heptahydrate to give the corresponding 7-hydroxy compound, which was rearranged into methyl 7-isopropyl-1,10-dimethyl-1,2,3,4-tetrahydroanthracene-1-carboxylate (14) possessing a rearranged linear abietane skeleton, by a treatment with boron trifluoride etherate. The reduction of 14 with lithium aluminum hydride afforded 7-isopropyl-1,10-dimethyl-1,2,3,4-tetrahydroanthracene-1-methanol (15). This was further converted into 7-isopropyl-1,1,10-trimethyl-1,2,3,4-tetrahydroanthracene. The mesylate of 15 was also rearranged into 2-isopropyl-5,9-dimethyl-7,8-dihydro-6H-cyclohepta[b]naphthalene, possessing a seven-membered A ring.
Synthesis and Properties of α,ω-Disubstituted Oligo(3-hexylthiophene)s and Oligothienoquinonoids in Head-to-head Orientation
Authors: Higuchi Hiroyuki , Nakayama Taketoshi , Koyama Haruki , Ojima Juro , Wada Tatsuo , Sasabe Hiroyuki
Published: July 2006

The two types of highly-ordered oligo(3-hexylthiophene)s in head-to-head orientation, a series of α,ω-disubstituted oligothiophenes and a series of bis(dicyanomethylene)oligothienoquinonoids, were synthesized. The properties of these compounds are discussed on the basis of the electronic spectra and cyclic voltammetry.
Deposition of Copper Using Photoexcited Riboflavin
Authors: Morishita Shinya , Suzuki Ken-ichi
Published: July 2006

In the presence of riboflavin and ethylenediaminetetraacetic acid (EDTA), deposition of copper was observed upon irradiation. Selective deposition of copper onto irradiated parts of a riboflavin-adsorbed alumina substrate was accomplished in an electroless copper plating solution containing EDTA. Two lines per millimeter were written on the substrate. The peel adhesion strength of the plated copper layer was comparable to that of a copper layer plated by a conventional method.
Visible Light Induced Hydrogen Evolution on CdS/K4Nb6O17 Photocatalyst
Authors: Yoshimura Joji , Tanaka Akira , Kondo Junko N , Domen Kazunari
Published: July 2006

The photocatalytic ability of CdS/K4Nb6O17 photocatalyst for H2 evolution by visible light irradiation was studied in connection with its structure. CdS/K4Nb6O17 was prepared by cation exchange reaction of K+ to Cd2+ ions in aqueous Cd(NO3)2 solution, followed by sulfurization in aqueous Na2S solution. The catalyst obtained by this procedure showed much higher H2 evolution activity in aqueous K2SO3 solution under visible light irradiation (λ > 420 nm) than a physical mixture of CdS and K4Nb6O17 powders. This result was interpreted as due to more intimate contact of CdS and K4Nb6O17 in CdS/K4Nb6O17 photocatalyst, which enabled the efficient transfer of excited electrons. The activity of the catalyst was greatly dependent on the sulfurization condition, with this optimum condition: at room temperature for one week. XRD, EXAFS, TEM, and UV-DRS showed that most CdS particles, ca. 10 nm in diameter, existed on the external surface of K4Nb6O17, while a small amount of CdS was inferred to be located at the interlayer space of K4Nb6O17 as ultra fine particles.
Atomic-Scale Surface Structures of TiO2(110) Determined by Scanning Tunneling Microscopy: A New Surface-Limited Phase of Titanium Oxide
Authors: Onishi Hiroshi , Fukui Ken-ichi , Iwasawa Yasuhiro
Published: July 2006

The structure transformation of a TiO2(110) surface was observed at atomic-scale resolution by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). Irregular corrugations on an argon-bombarded TiO2(110) surface crystallized to stacked (1 × 1) terraces by vacuum annealing at 600—800 K. The terraces grew in dimension to be as large as 30 × 30 nm2 at 900 K. The unoccupied surface states localized on individual Ti4+ ions were resolved on a (1 × 1) terrace. The position of the Ti4+ ions was probed by imaging adsorbed formate ions. Annealing at higher temperatures resulted in the formation of a wide row structure comprising double strands. Imaging of individual adsorbed formate ions was used to grade possible structure models by probing Ti ions exposed on the surface; thereby, an added Ti2O3 row model, which is a new surface-limited phase of titanium oxide consisting of Ti3+ ions of the optimum six-fold coordination, was concluded for the double-strand structure. These results demonstrate the ability of probing experiments with an adsorbed molecule to determine the chemical nature of imaged sites on multi-component materials by STM.
Quantum Reactive Scattering Calculation for Four-Atom Chemical Reaction Systems: Application of a Fixed-Angle Approximation
Authors: Takayanagi Toshiyuki
Published: July 2006

An approximate quantum mechanical method is described for calculating reaction probabilities for the general four-atom chemical reaction AB + CD → A + BCD. By applying a fixed-angle approximation, reaction probabilities are calculated for the H2 + CN → H + HCN reaction on a semiempirical potential energy surface. The calculated results are compared favorably with those of quasiclassical trajectory calculations.
Syntheses and Some Properties of S-Bridged Pentanuclear Co(III)–Hg(II) or Rh(III)–Hg(II) Complexes with 2-Aminoethanethiolate. Crystal Structures of [{Rh(aet)3}2(HgCl2)3] and [{Rh(aet)3}2Hg3(NO3)4](NO3)2
Authors: Okamoto Ken-ichi , Kageyama Yuichi , Konno Takumi
Published: July 2006

S-Bridged pentanuclear complexes [{Rh(aet)3}2(HgCl2)3] (1) and [{M(aet)3}2Hg3(NO3)4]2+ (M = Rh(III), 2 and Co(III), 3) were newly prepared by the reaction of fac(S)-[M(aet)3] with HgCl2 or Hg(NO3)2; where aet denotes 2-aminoethanethiolate. The crystal structures of 1 and 2 were determined by X-ray diffraction methods. These complexes consist of two fac(S)-[M(aet)3] subunits, three Hg atoms, six chlorides (for 1) or nitrates (for 2), and water molecules, in which the configuration of the five metals is an approximately regular trigonal-bipyramid. Each Hg atom in these complexes takes a highly distorted tetrahedral geometry. There are three kinds of nitrates in [{Rh(aet)3}2Hg3(NO3)4](NO3)2, bridged bidentate, monodentate, and anion. Both 1 and 2 possess a novel chirality due to the helical structures of three Rh–S–Hg–S–Rh chains. Although 1 was insoluble in water, 2 and 3 were optically resolved by fractional precipitation. These complexes were characterized by their absorption, CD, and NMR spectra. The coordinated nitrates in 2 and 3 were readily replaced by water molecules when dissolved in water. The stabilities of the S-bridged pentanuclear complexes are also discussed.
Electrogenerated Acid as an Efficient Catalyst for Alcoholyses and Hydrolyses of Epoxides
Authors: Safavi Afsaneh , Iranpoor Nasser , Fotuhi Lida
Published: July 2006

The electrochemical transformation of different epoxides to their corresponding β-alkoxy alcohols and diols was achieved by using an electrogenerated acid-catalyst. A competitive ring-opening reaction of activated epoxides in the presence of deactivated epoxides was also successfully carried out in both alcohols and water.
Rearrangement Approaches to Cyclic Skeletons. IX. Stereoselective Total Synthesis of (±)-Camphorenone Based on a Ring-Contraction of Bicyclo[3.2.1]oct-6-en-2-one. Reliable One-Step Diazo Transfer Followed by a Wolff Rearrangement
Authors: Uyehara Tadao , Takehara Naohiko , Ueno Masako , Sato Toshio
Published: July 2006

A direct diazo transfer reaction to bicyclo[3.2.1]oct-6-en-2-ones and related compounds was accomplished by treatments with 2,4,6-triisopropylbenzenesulfonyl azide and potassium t-butoxide at −78 °C in THF. A Wolff rearrangement of the resulting α-diazoketones in the presence of water gave ring-contraction products, bicyclo[2.2.1]heptenecarboxylic acids. Using these two transformations the total synthesis of (±)-camphorenone was achieved stereoselectively, starting from 1-methoxybicyclo[2.2.2]oct-5-en-2-one.
Preparation and Characterization of DNA–Lipoglutamate Complexes
Authors: Sato Toshinori , Kawakami Takashi , Shirakawa Nobuaki , Okahata Yoshio
Published: July 2006

We newly prepared DNA–lipoglutamate polyion complexes by mixing aqueous solutions of DNA and cationic lipoglutamates such as α,γ-dibutyl glutamate (2C4N+), α,γ-dihexyl glutamate (2C6N+), and α,γ-dioctyl glutamate (2C8N+). Formation of the DNA–lipoglutamate complex was confirmed by gel chromatography, elemental analysis, CD spectra, and light scattering measurement. Compaction of DNA by binding with the cationic lipoglutamate was revealed by multi-angle light scattering. The DNA–lipoglutamate complexes showed the high stability for enzymatic hydrolysis by DNase I, which was confirmed by a quartz-crystal microbalance (QCM) technique. The DNA–lipoglutamate complexes showed the strong interactions with the lipid membranes and tumor cells compared with native DNA.
Total Synthesis of dl-Ascofuranone and Related Compounds
Authors: Saimoto Hiroyuki , Ohrai Shin-ichiro , Sashiwa Hitoshi , Shigemasa Yoshihiro , Hiyama Tamejiro
Published: July 2006

Convergent synthesis of an antitumor protective agent, ascofuranone, was accomplished by (1) preparation of the terpenoid side chain having a furanone moiety, (2) coupling the side chain with a protected phenol derivative, and (3) deprotection to regenerate the hydroxyl groups. This strategy was successfully applied to the synthesis of oxidized and cyclized analogs of ascofuranone. Some of the ascofuranone derivatives were found to inhibit the growth of P388 leukemia cells.
Syntheses and Characterization of Cubane-Type Clusters with Molybdenum–Iron–Sulfur (Mo3FeS4) or Molybdenum–Nickel–Sulfur (Mo3NiS4) Cores. X-Ray Structures of [Mo3FeS4(H2O)10](CH3C6H4SO3)4·7H2O and [Mo3FeS4(H2O)(NH3)9]Cl4, and Discrete Variational (DV)-Xα Calculation of the Electronic Structures of [Mo3FeS4(H2O)10]4+, [Mo3FeS4(H2O)(NH3)9]4+, and [Mo3NiS4(H2O)10]4+
Authors: Shibahara Takashi , Sakane Genta , Naruse Yoshiyuki , Taya Kazuhisa , Akashi Haruo , Ichimura Akio , Adachi Hirohiko
Published: July 2006

Reaction of the incomplete cubane-type cluster [Mo3S4(H2O)9]4+ (A) with iron gives a novel cubane-type aqua cluster [Mo3FeS4(H2O)10](CH3C6H4SO3)4·7H2O (B′). An ammonia coordinated derivative cluster [Mo3FeS4(H2O)(NH3)9]Cl4 (C′) is also synthesized. X-ray structural analyses of B′ and C′ revealed that the clusters, [Mo3FeS4(H2O)10]4+ (B) and [Mo3FeS4(H2O)(NH3)9]4+ (C), have an approximate symmetry of C3v. The iron atom has fairly regular tetrahedral geometry in both clusters. The effective magnetic moments of B′ at 2.16 K and 269.95 K are 2.78 and 3.26 B.M., respectively. 57Fe-Mössbauer spectroscopy showed that the oxidation states of iron in B′ and C′ were assignable to be +2.39 and +2.54, respectively, which indicates that the reaction is a reductive addition of an iron atom to the Mo3S4 core in A. The cyclic voltammograms of A, B, and [Mo3NiS4(H2O)10]4+ (D) show three consecutive one electron reductive steps, respectively, and the oxidation states of metals in B and D are assigned as MoIVMoIII2MII (M = Fe, Ni). Discrete variational (DV)-Xα calculation of B, C, and D explains the magnetic behavior, XPS spectra, and reactivity toward CO, C2H2, and C2H4.
Photodissociation of CF2Br2 at 248 nm: A Time-Resolved Absorption Study
Authors: Vatsa Rajesh Kumar , Kumar Awadhesh , Naik Prakash Dattatray , Rama Rao Kuchimanchi Venkata Subba , Mittal Jai Pal
Published: July 2006

Photodissociation of CF2Br2 at 248 nm has been studied in the gas phase using time-resolved optical absorption spectroscopy. A transient absorption spectrum in the range of 200—320 nm with λmax ≈ 260 nm is observed and has been assigned to the primary photodissociation product, the CF2Br radical. The absorption cross section of this radical at 260 nm has been found to be (1.05 ± 0.2) × 10−18 cm2 molecule−1. The rate constant for CF2Br dimerization is evaluated to be (3.0 ± 0.6) × 10−12 cm3 molecule−1 s−1. Laser fluence dependence in the secondary photodissociation of CF2Br radical is discussed.
Silver Ion Selective Extraction with Dithiaza-, Tetrathiaza-, and Tetrathiadiazacrown Ether Derivatives
Authors: Sakamoto Hidefumi , Ishikawa Junichi , Otomo Makoto
Published: July 2006

Dithiazacrown, tetrathiazacrown, and two tetrathiadiazacrown ether derivatives, bearing a phenyl group on each nitrogen atom at the periphery, were synthesized, and the solvent extractions of some transition metal ions with these compounds were carried out using an H2O–1,2-dichloroethane system. All of the thiazacrown compounds employed exhibited Ag+ selectivity, and formed 1 : 1 : 1 complexes of Ag+ : ligand : laurate ion as a counter anion to be extracted into a 1,2-dichloroethane solution. The extractabilities (extraction constants, Kex) for Ag+ decreased in the order: 7,16-diphenyltetrathia-7,16-diaza-18-crown-6 (3) (log Kex = 1.18 ± 0.13) > 13-phenyltetrathia-13-aza-15-crown-5 (2) (0.75 ± 0.09) > 7-phenyldithia-7-aza-9-crown-3 (1) (−0.47 ± 0.06) > 13,16-diphenyltetrathia-13,16-diaza-18-crown-6 (4) (−0.62 ± 0.16).
Enhanced Membrane-Perturbing Activities of Bundled Amphiphilic α-Helix Polypeptides on Interaction with Phospholipid Bilayer
Authors: Sakamoto Seiji , Mihara Hisakazu , Matsuo Eitarou , Niidome Takuro , Anzai Kazunori , Kirino Yutaka , Aoyagi Haruhiko
Published: July 2006

The 24-peptide 46, designed to take an amphiphilic α-helix structure, had strong activity toward phospholipid membranes and could form ion-channels selective for cations on a planar membrane [J. Biol. Chem., 266, 20218 (1991)]. Four, six, and eight segments of the peptide 46 were bundled (4α-46, 6α-46, and 8α-46) on dendrimers consisting of Lys residues. These bundled peptides had highly α-helical structures with an enhanced α-helicity compared with the original 46 peptide. These peptides had hydrophobic pockets inside the bundle structures in aqueous solution in which the fluorescent hydrophobic probe, 1-anilino-8-naphthalenesulfonate (ANS), bound strongly. The peptides caused much leakage of carboxyfluorescein from small unilamellar vesicles of phospholipids at much lower concentrations of peptides than 46 did. Furthermore, the peptides induced the vesicle fusion at lower concentrations than those of the leakage. Four segments of the analogous 24-peptide 46S, in which six Ser residues were introduced instead of Ala and Leu residues in 46, were bundled by the same method (4α-46S). The fluorescent properties of the Trp residues incorporated at the 1 and 12 positions in 4α-46S, respectively, indicated that the centers of the helices were in more hydrophobic conditions than the N-terminal was. These facts caused us to conclude that the bundled conformation increased the perturbation of the phospholipid membrane, and as a result, the peptides were embedded in the membrane.
Antioxidant Activities of Dihydric Phenol Derivatives for the Autoxidation of Tetralin
Authors: Yamamura Tatsuo , Nishiwaki Kazuhiro , Tanigaki Yasumitsu , Terauchi Susumu , Tomiyama Shogo , Nishiyama Tomihiro
Published: July 2006

The antioxidant activities of dihydric phenols, such as catechol, resorcinol, and hydroquinone, and their twenty-three alkyl and benzyl substituted derivatives were evaluated by means of an oxygen-absorption method at 60 °C for determining the oxidation of tetralin. Catechols exhibited a much higher stoichiometric factor (2.0—2.3) compared with those of other compounds. The stoichiometric factors of hydroquinones (0.6—1.1) are almost half those of catechols, and are lower for the resorcinols (0.3—0.6). In addition, the rates of oxidation during the induction period (Rinh) were 1.1—1.6 × 10−6, 3.0—3.8 × 10−6, and 13.3—18.4 × 10−6 M min−1 for catechols, hydroquinones, and resorcinols, respectively. According to these results, catechols and hydroquinones are efficient antioxidants, and their activities may be dependent on the stability of phenoxyl radicals as oxidation products due to the formation of the quinone structure. Furthermore, the stability of phenoxyl radicals derived from catechols is higher than that of those from hydroquinones. In spite of having two OH substituents, resorcinols behave as monohydric phenols in the reaction with peroxyl radicals.
Theoretical Analysis of Adsorption Properties and Vibrational Behavior of O2 on Ag (110) Surface with Ab Initio CM and DAM Calculations
Authors: Fan Kangnian , Wang Wenning , Deng Jingfa
Published: July 2006

Chemisorption properties and vibrational behaviors of molecular oxygen on Ag (110) surface have been studied by the cluster model (CM) and dipped adcluster model (DAM) with an Ag6 cluster. Two stable states, 1A1 [] and 3A2 [001], have been found and assigned to peroxide (O22−) and superoxide (O2−) species, respectively. Theoretically predicted adsorption geometries and vibrational frequencies for these states are similar to those measured in the experiments. With the DAM method, the calculated adsorption energies agree well with the experimental value. The O22− species is predicted to be more stable than the O2− species. Cluster size and basis set effects have also been investigated.
Synthesis and Characterization of Tetranuclear Manganese(III) Complexes with 2,6-Bis(salicylideneaminomethyl)-4-methylphenol
Authors: Mikuriya Masahiro , Nakadera Keiichi , Kotera Takanori , Tokii Tadashi , Mori Wasuke
Published: July 2006

Tetranuclear manganese(III) complexes with 2,6-bis(salicylideneaminomethyl)-4-methylphenol (H3L), [Mn4(L)2(O)2(CH3COO)2]·2CH3CN (1) and [Mn4(L)2(O)2(C6H5COO)2]·2CH3OH (2), have been synthesized and characterized by infrared and electronic spectra, cyclic voltammetry, and temperature dependence of magnetic susceptibilities (4—300 K). The molecular structure of 1 was determined by single-crystal X-ray structure analysis. Complex 1 has a tetranuclear structure, in which two incomplete cubanes are sharing faces by the oxo-bridges. The magnetic susceptibility data show an overall antiferromagnetic interaction.
Variation of Formation Constants of Adducts of Lanthanoid(III) Chelates with Benzoic and Phenylacetic Acids across the Series
Authors: Hasegawa Yuko , Ohyama Takeshi , Katsuta Shoichi
Published: July 2006

The extraction behavior of lanthanoids(III) with 1-(2-thienyl)-4,4,4-trifluoro-1,3-butanedione (TTA) and benzoic or phenylacetic acid from 0.1 M sodium perchlorate media into chloroform has been examined at 298 K. The extraction curves are interpreted by the extraction of the adducts of the TTA chelates accompanied with two molecules of the carboxylic acids at maximum as well as the extraction of the TTA chelate. The adduct formation constants decrease generally with the atomic number, but in the middle of the series, they change only slightly, then decrease more rapidly for the heavy elements. Such a trend indicates a change of the coordination number in the middle of the series.
Versatility in Complexation of Six-Membered Heterocyclic Guests by Singly Bridged Triarylmethanol Hosts. X-Ray Crystal Structures and Thermal Stabilities of Inclusion Compounds with Piperidine, Thioxane/Dioxane, and Morpholine
Authors: Csöregh Ingeborg , Gallardo Olga , Weber Edwin , Bourne Susan A , Dörpinghaus Norbert
Published: July 2006

9-Phenylfluoren-9-ol (1), 2,7-dibromo-9-phenylfluoren-9-ol (2), and 9-phenylethynylfluoren-9-ol (3) enclathrate different six-membered heterocyclic guests involving piperidine, thioxane, dioxane, and morpholine. X-Ray crystal structure determinations of corresponding inclusion compounds [1·piperidine (1 : 1), 1·thioxane·dioxane (2 : 2 : 1), 2·morpholine (1 : 2), and 3·morpholine (1 : 1)] are reported, showing remarkable variety in the packing relations. Host compound 1 forms H-bonded 1 : 1 host : guest units with both piperidine and thioxane, but in the latter case additional dioxane guests are incorporated in the crystal, thus yielding a ternary complex. Host compound 3 is capable of forming closed loops of hydrogen bonds with full hydrogen bond saturation in its inclusion compound with morpholine, whereas in the related morpholine complex of 2 H-bonded 1 : 2 associates are created without maximal saturation of the hydrogen bonds, and with different binding modes for the two guests of the stoichiometric unit. In the crystals, the various H-bonded host-guest units are linked together by Van der Waals’ forces, occasionally supported by weak electrostatic interactions. The stabilities of the four different inclusion compounds were studied by thermal analysis indicating complex decomposition modes.
Reaction of Imines with Naphthoquinones and 2-(Dicyanomethylene)-1,3-indandione
Authors: Gomaa Mohsen Abdel-Motaal
Published: July 2006

Benzylideneanilines react with 2,3-dichloro-1,4-naphthoquinone and 2,3-dicyano-1,4-naphthoquinone to give 2-arylamino-3-chloro-1,4-naphthoquinones and 2-arylamino-3-cyano-1,4-naphthoquinones respectively together with the corresponding aldehydes. Similarly benzylideneanilines react with 2-(dicyanomethylene)-1,3-indandione to give 2-arylamino-2-(1,3-dioxo-2-indanylidene)acetonitriles.
New Synthetic Route to 10,11-Dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imines through Photoamination of 5-Alkoxy- and 5-Hydroxy-5H-dibenzo[a,d]cycloheptenes Followed by a Transannular Reaction with Acetic Acid
Authors: Yasuda Masahide , Wakisaka Tomoko , Kojima Ryuji , Tanabe Kimiko , Shima Kensuke
Published: July 2006

The photoadditions of ammonia and alkylamines (RNH2) to 5-hydroxy- and 5-alkoxy-5H-dibenzo[a,d]cycloheptene derivatives (2) occurred at the C10–C11 double bond upon the irradiation of 2 with RNH2 in the presence of p-dicyanobenzene. The resulting 5-substituted 10-alkylamino-10,11-dihydro-5H-dibenzo[a,d]cycloheptenes were converted to 5-substituted N-alkyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imines by a treatment with AcOH.
Charge-Transfer Interaction and Molecular Arrangement in the Crystals of 2-(p-Nitrophenoxy)ethyl Ethers and Amines
Authors: Mazaki Yasuhiro , Mutai Kiyoshi
Published: July 2006

X-Ray crystallographic analysis of the Acceptor-(CH2)2-Donor type compounds, p-O2NC6H4OCH2CH2OAr (Ar = m- and p-Me2NC6H4, and m-Et2NC6H4) and p-O2NC6H4OCH2CH2N(CH3)C6H4OMe-p, has been carried out. Among these, only m-dimethylamino derivative (1) gives dark red prisms in which a close arrangement of the electron-donor and acceptor groups is observed. With regard to the central C–C bond in ArO–C–C–OAr′ or ArO–C–C–NAr′, three of the above-mentioned four compounds show gauche conformation: 1 is the exception. The preference of the gauche , probably characteristic of O–C–C–O (or –N) group, is suggested to be due to a small energy difference between the trans and gauche forms by using the MM2 and the PM3 approximation. Charge-transfer interaction energy in 1 as an intermolecular force is estimated to be barely large enough to make the trans conformation favorable over the gauche.
Chiral Discrimination on Polysaccharides Derivatives
Authors: Yashima Eiji , Okamoto Yoshio
Published: July 2006

Chromatographic enantioseparations, particularly resolution by high-performance liquid chromatography (HPLC), have advanced considerably in the past decade, and have become a practically useful method not only for determining their optical purity, but also for obtaining optical isomers. The preparation of a chiral stationary phase (CSP) capable of effective chiral recognition is the key to this separation technique. We have found that polysaccharide derivatives, particularly cellulose esters and phenylcarbamate derivatives of cellulose and amylose, are very effective CSPs, and can resolve a wide range of racemates, including drugs. A variety of polysaccharides derivatives involving tribenzoates and tris(phenylcarbamates) of cellulose and amylose were prepared and their chiral recognition abilities were evaluated as CSPs in HPLC. The chiral recognition and resolving ability of the derivatives depend greatly on the substituents introduced on the phenyl moieties. The introduction of electron-donating or electron-withdrawing substituents improved the chiral recognition ability. Among the many derivatives of polysaccharides, 3,5-dimethylphenylcarbamates of cellulose and amylose and cellulose tris(4-methylbenzoate) show high chiral recognition, which has allowed the resolution of more than 80% of the racemates tested. These CSPs can be used for both analytical and preparative separations of enantiomers. Some significant mechanistic aspects are also briefly reviewed.
Ultrafast Photochemistry of Ammonia Clusters: Formation and Decay of Hypervalent Molecular Clusters Containing the NH4 Radical
Authors: Fuke Kiyokazu , Takasu Ryozo
Published: July 2006

The photochemical reaction of ammonia clusters in the first excited state was studied by a femtosecond pump-probe technique and time-of-flight mass spectroscopy. Small ammonia clusters containing the NH4 radical were probed by a resonance enhanced two-photon ionization method. The NH4 radical is formed within 0.5 ps, and decomposes with a lifetime of 13 ps. The ammonia dimer ion was found to be formed mainly through the one-photon ionization of a new photolysis product such as an excited-state NH4*–NH2. This intermediate may correspond to a cage product in the predissociation process of larger ammonia clusters; its formation and decay times are ca. 1 ps and > 1 ns, respectively. We also examined the lifetimes of NH4(NH3)n using the pump-probe technique with nanosecond lasers. The lifetime of NH4 was found to be elongated by more than 106 times in ammonia clusters. The mechanism of the formation and decay processes for these species as well as for the resonance-enhanced two-photon ionization of ammonia clusters were discussed on the basis of the present results in conjunction with theoretical results from literature.
An Interpretation of Convergent Linear Energy Relationships Observed for 1 : 1 Hydrogen-Bond Complexation of OH– and NH–Acids with Phosphorus Compounds in Carbon Tetrachloride
Authors: Mishima Shozi , Nakajima Tsuyoshi
Published: July 2006

A thermodynamic interpretation is presented of the convergent linear relationships observed among the log K (K; equilibrium constant) values of 1 : 1 hydrogen-bond complexation of nine OH– and NH–acids against five phosphorus compounds in CCl4. Straight lines converging on a single point are plotted from the log K values at different temperatures. The slopes of the lines correspond to the temperature ratio and the convergence point reflects the apparent constant value of ΔS° (−35.4 J mol−1 K−1). Sets of family-independent or family-dependent straight lines all of which converge on the same point can be plotted from the log K values of the acids (or bases) against two reference bases (or acids). The convergence point also reflects the constancy of the apparent ΔS° value and the slopes of the lines correspond to the ΔH° ratio. The thermodynamic features can be correlated with local structures of the acids and bases. The interpretation presented here can be applied to other systems and is of importance as a new view of 1 : 1 hydrogen-bond systems.
Solvent Extraction of Thallium(I) with Chelating Extractants Coordinating through Oxygen Atoms
Authors: Sekine Tatsuya , Tsuda Junko
Published: July 2006

The solvent extraction of thallium(I) in aqueous 0.1 mol dm−3 sodium nitrate solutions with seven chelating extractants [(HA), 1-phenyl-1,3-butanedione (Hbza); 1,3-diphenyl-1,3-propanedione (Hdbm); 4,4,4-trifluoro-1-phenyl-1,3-butanedione (Hbfa); 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (Htta); 2-hydroxy-4-isopropyl-2,4,6-cycloheptatrien-1-one (Hipt); 5,7-dichloro-8-quinolinol (Hdcox); and 1,1,1-trifluoro-4-mercapto-4-(2-thienyl)-3-buten-2-one (Hstta)] into chloroform was studied in the absence and presence of tetrabutylammonium ions (tba+) or trioctylphosphine oxide (TOPO). The TlA type chelates were extracted, and, except for Hbza and Hdbm, tba+TlA2−-type ternary complexes were extracted. However, the extraction of adduct chelates with TOPO was not obtained. A comparison of the stability, liquid–liquid partition, and acceptability of a further ligand in the organic phase was made with TlA, AgA, and LiA when A− was 1,1,1-trifuluoro-3-(2-thienyl)-2,4-butanedionate ion (tta−) and the ligand was TOPO or tta−.
Structures and Properties of Vanadium(III) Complexes with 1,2-Diaminoethane-N,N′-diacetate-N,N′-dipropionate and N,N-Bis(carboxymethyl)-β-alanate
Authors: Kanamori Kan , Kumada Junko , Yamamoto Mayumi , Okayasu Takako , Okamoto Ken-ichi
Published: July 2006

The crystal structures of K[V(eddda)]·2H2O (1) and [V(β-alada)(H2O)2]·H2O (2) were determined by X-ray crystallography, where eddda and β-alada denote 1,2-diaminoethane-N,N′-diacetate-N,N′-dipropionate and N,N-bis(carboxymethyl)-β-alanate, respectively. The crystal of 1 is monoclinic, space group P21/n, a = 10.2753(8), b = 11.3007(8), c = 15.278(2) Å, β = 104.857(9)°, V = 1714.7(3) Å3, Z = 4, and R = 0.052. The crystal of 2 is orthorhombic, space group P212121, a = 7.451(1), b = 11.852(2), c = 13.403(2) Å, V = 1183.6(3) Å3, Z = 4, and R = 0.053. Complexes 1 and 2 adopt a hexacoordinate structure in contrast to the heptacoordinate one of the closely related ethylenediamine-N,N,N′,N′-tetraacetate and nitrilotriacetate complexes. Complexes 1 and 2 yield oxo-bridged dinuclear complexes upon base hydrolysis. The reaction of 2 with CO32− results in the formation of the heptacoordinate species with the bidentate carbonato ligand.
A Novel Methylation of Allylic Alcohols Using cis-Dichlorobis(triphenylphosphine)platinum(II)–Tin(II) Chloride Dihydrate Complex Catalyst
Authors: Sakamaki Hiroshi , Kameda Noriyuki , Iwadare Tsukasa , Ichinohe Yoshiyuki
Published: July 2006

The reaction of allylic alcohols in benzene–methanol (3 : 2) solvent in the presence of cis-dichlorobis(triphenylphosphine)platinum(II)–tin(II) chloride dihydrate complex catalyst afforded allylic methyl ethers. The structure of the obtained compounds was identified by direct comparison with authentic sample. Cholest-4-en-3α-ol, with a quasi-axial hydroxy group, gave a quantitative yield of 3α-methoxycholest-4-ene. On the other hand, cholest-4-en-3β-ol, with a quasi-equatorial hydroxy group, yielded 3β-methoxycholest-4-ene preferentially, but it also yielded 3α-methoxy compound as a by-product, lowering the selectivity of the reaction.
Mass-Spectrometric Study on Ion–Molecule Reactions of CF3+ with PhX [X = H, CH3, and C2Hn (n = 1, 3, 5)] at Near-Thermal Energy
Authors: Tsuji Masaharu , Aizawa Masato , Nishimura Yukio
Published: July 2006

The gas-phase ion-molecule reactions of CF3+ with benzene, toluene, ethylbenzene, styrene, and ethynylbenzene have been studied at near-thermal energy using an ion-beam apparatus. The major product channels are electrophilic addition followed by HF elimination for benzene (93.4 ± 2.2%), toluene (84.3 ± 2.4%), and ethynylbenzene (76.9 ± 0.9%). The dominant product channels for ethylbenzene are electrophilic addition followed by C2H4 and C2H4+HF eliminations (78.9 ± 4.7%), while those for styrene are electrophilic addition followed by one or two HF eliminations and C2H2F2 elimination (91.7 ± 5.4%). Only ethynylbenzene gives an initial adduct ion with a small branching ratio of 6.2 ± 0.4%. As minor product channels, hydride transfer occurs for benzene (6.6 ± 2.2%) and toluene (7.8 ± 1.5%), and charge transfer takes place for toluene (7.9 ± 2.0%), styrene (8.3 ± 1.4%), and ethynylbenzene (6.2 ± 0.4%). The reaction mechanisms are discussed on the basis of product ion distributions and semi-empirical calculations of potential energies of reaction pathways.
Preparation of New Nitrogen-Bridged Heterocycles. 40. Synthesis of 1,4-Dihydropyrido[2,3-b]indolizin-4-one Derivatives
Authors: Kakehi Akikazu , Ito Suketaka , Hayashi Shigetoshi , Fujii Takashi
Published: July 2006

The title compounds, 1,4-dihydropyrido[2,3-b]indolizin-4-one derivatives, were prepared in moderate to good yields via the N-formylation of some 3-acetyl-2-(alkylamino)indolizines with triethyl orthoformate and acetic anhydride in the presence of zinc chloride followed by the intramolecular dehydration of the resulting 3-acetyl-2-(N-alkylformamido)indolizines under strong alkaline conditions.
Optical Resolution of dl-threo-2-(2,4-Difluorophenyl)-2-[1-(methylthio)ethyl]oxirane: Its Application to the Synthesis of SM-9164, a Biologically Active Enantiomer of Antifungal Agent SM-8668
Authors: Miyauchi Hiroshi , Ohashi Naohito
Published: July 2006

A racemate of threo-2-(2,4-difluorophenyl)-2-[1-(methylthio)ethyl]oxirane was separated into two enantiomers by reaction with a chiral carboxylic acid, followed by separation of the resultant diastereomers, hydrolysis of the ester, and dehydration of the 1,2-diol to the oxirane. This new optical resolution method was applied to the synthesis of SM-9164, a biologically active enantiomer of antifungal agent SM-8668. Thus, the optically active isomer of SM-8668 was prepared efficiently in eight steps from m-difluorobenzene.
Synthesis and Dynamic Stereochemistry of Di-1-azulenyl(1- and 2-naphthyl)methyl Hexafluorophosphates. Clear Evidence of the One-Ring Flip Mechanism of a Molecular Propeller by Controlling the Flipping Ring
Authors: Ito Shunji , Fujita Miwako , Morita Noboru , Asao Toyonobu
Published: July 2006

In order to control the flipping ring of a molecular propeller and to obtain clear evidence of a one-ring flip mechanism, stable carbocations, di-1-azulenyl(1-naphthyl and 2-naphthyl)methyl cations, bis(3-methyl-1-azulenyl)(1-naphthyl (5b) and 2-naphthyl (6b))methyl cations, and bis(3,6-di-t-butyl-1-azulenyl)(1-naphthyl and 2-naphthyl)methyl cations were synthesized by hydride abstraction of the corresponding hydrocarbons. These cations showed extreme stabilities with high pKR+ values (10.3—12.7). The dynamic stereochemistries of 5b and 6b were studied by temperature-dependent 1H NMR spectra, which were analyzed by a flip mechanism. While the 1H NMR signals of 6b did not resolve satisfactorily, the low-temperature 1H NMR spectra of 5b showed that the flipping ring of the molecular propeller was controlled by a one-ring flip of the 1-naphthyl group. These analyses afforded clear evidence of the one-ring flip mechanisms of (1-azulenyl)methyl cations.
Effects of Trehalose on the Water Structure in Yeast Cells as Studied by in vivo 1H NMR Spectroscopy
Authors: Sakurai Minoru , Kawai Hidetoshi , Inoue Yoshio , Hino Akihiro , Kobayashi Syouichi
Published: July 2006

Trehalose-containing and -lacking yeast cells are prepared, and in vivo  1H NMR spectra are measured in order to investigate effects of this sugar on water structure in the cells. The T2 relaxation times for the intracellular water protons are measured as a function of water content in the yeast cells. The results indicate that the intracellular water is categorized into at least two groups: highly immobilized water (T2   5 ms), assigned to bound water, and intermediate water. One of the most important findings is that the relative population of bound water is drastically increased by the accumulation of trehalose. About 80% of the intracellular water in the trehalose-containing yeast cells is attributed to bound water. Similar results are obtained for trehalose-containing and -lacking model membranes prepared from dipalmitoylphosphatidylcholine (DPPC). Additionally, DSC measurements are carried out to examine effects of trehalose on the gel–liquid crystalline transition temperature of the DPPC membranes. On the basis of these results, a brief discussion is given about the role of trehalose as a stress tolerance-inducer in cells.
Decomposition of Cyclohexanol on the Spinel System CuCr2−xFexO4
Authors: Ahmed Ashfaq , Oak S G , Darshane V S
Published: July 2006

The System CuCr2−xFexO4 has been studied with a view to correlate the catalytic behavior of spinels on the decomposition of cyclohexanol. All the compositions between 0.0 ≤ x ≤ 1.0 had cubic symmetry and p-type semiconductivity except the compound CuCr2O4 (x = 0.0) which showed tetragonal symmetry. The activation energy for the electronic conduction varied between 0.38 and 0.13 eV. The Seebeck coefficient (α) was found to increase with increases in ‘x’. Catalytic evaluation was done in the temperature range 200—400 °C using cyclohexanol as a probe molecule. Our results show CuCrFeO4 to be a better catalyst for cyclohexanol decomposition than CuCr2O4. The percent decomposition of alcohol increased with increases in mobility of charge carriers and decreases in values of activation energy. Further, dehydrogenation selectivity increased with increases in p-type behavior of the compositions from CuCr2O4 to CuCrFeO4. X-ray and IR studies indicated that the spinel catalysts are quite stable over the temperature range investigated.
Palladium-Catalyzed Double and Single Carbonylation of Aryl Halides and Allylic Compounds
Authors: Yamamoto Akio
Published: July 2006

After a brief introduction summarizing the author’s previous work concerning the double carbonylation of aryl halides catalyzed by palladium complexes, newly found catalytic processes (1) for converting allylic formates and chlorides into β,γ-unsaturated acids and (2) the double carbonylation of allylic chlorides to β,γ-unsaturated α-keto amides are described. Mechanisms which reasonably account for the catalytic processes are proposed on the basis of studies concerning the properties of the organopalladium complexes.
Dinuclear Oxomolybdenum(V) and Oxotungsten(V) Complexes of the Hexadentate Ligands N,N,N′,N′-Tetrakis(2-pyridylmethyl)ethylenediamine and Its Propylenediamine Analog
Authors: Hazama Ryoichi , Umakoshi Keisuke , Ichimura Akio , Ikari Shinji , Sasaki Yoichi , Ito Tasuku
Published: July 2006

Four new dinuclear oxomolybdenum(V) and oxotungsten(V) complexes, [M2O2(μ-O)2(μ-tpen-N,N′)]2+ and [M2O2(μ-O)2(μ-tppn-N,N′)]2+ (tpen = N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine, tppn = N,N,N′,N′-tetrakis(2-pyridylmethyl)propylenediamine ((R)- and (R,S)-forms have been used); M = Mo, W), have been prepared. X-Ray structural analysis (except for the W–tppn complex) revealed ‘basket type’ structures similar to those of the edta and pdta analogs, [M2O2(μ-O)2(μ-edta-N,N′ or μ-pdta-N,N′)]2− (edta = ethylenediamine-N,N,N′,N′ -tetraacetate(4−); pdta = propylenediamine-N,N,N′,N′-tetraacetate(4−)).

The metal–metal distances of the Mo–tpen, Mo–tppn, and W–tpen complexes are 2.546(1), 2.541(2), and 2.561(1) Å, respectively. Asymmetric distortion along the Mo–Mo axis of the Mo–R-tppn complex is in the opposite direction to that of the corresponding R-pdta complex. The difference may be related to the longer Mo–N(pyridyl) distance and larger N(pyridyl)–Mo–N(pyridyl) angle of the tppn complex as well as the direction of skew conformation of five membered chelate rings M–N(pyridyl)–C–C–N(amine). Electronic absorption spectral patterns of the new complexes are generally similar to the corresponding edta complexes. Circular dichroism (CD) spectra of the R-tppn complexes in the region >300 nm show a pattern nearly enantiomeric to those of the corresponding R-pdta complexes, indicating that the asymmetric distortion is retained in water and in acetonitrile. Kinetic parameters of the inversion of the pseudo-gauche conformation of diamine moiety in the tpen complexes were evaluated from the temperature dependence of 1H NMR spectra in acetonitrile. ΔH‡’s are significantly larger and ΔS‡’s are significantly more positive than those of the edta analogs. The inversion may take place through dissociative bond cleavage of the metal–N(pyridyl) bond. The new dimolybdenum complexes show two reversible one electron reduction processes (at −1.40 and −1.86 V vs. Ag/Ag+) in acetonitrile (0.1 mol dm−3). Electronic absorption spectrum of the Mo2(IV,V) mixed valence state was obtained using spectroelectrochemical techniques.

(Remark: This summary is partially truncated in the html because it exceeds the limit of the system (4000 characters per note). The complete text is given in the pdf.)
A Heuristic Molecular-Dynamics Approach for the Prediction of a Molecular Crystal Structure
Authors: Tajima Nobuo , Tanaka Takayuki , Arikawa Tomoko , Sakurai Takashi , Teramae Shoichi , Hirano Tsuneo
Published: July 2006

A general method has been developed to predict the structures of molecular crystals without any constraints on the space symmetry nor on the lattice constants. A constant-pressure molecular dynamics (MD) technique, treating the lattice constants as variables, is employed in the search of candidate structures (“shaking” process). A heuristic MD search is proposed to reduce redundant sampling in the shaking process. The structures of the thus sampled species are further optimized in geometry by the steepest descent method (“quenching” process). This general method was coded in a program named MDCP (Molecular Dynamics for Crystal Packing), and was applied to the prediction of the crystal structures of CO2, benzene, and pyrimidine molecules, as test examples. For CO2 and benzene crystals, the experimentally observed structures were well reproduced through our method. For pyrimidine, however, a slight difficulty was observed under the atom–atom potentials employed here, although near-miss structures were frequently encountered.
Hydrate Cluster Formation of Diol Compounds in Aqueous Solution
Authors: Takahashi Satoru , Nishi Nobuyuki
Published: July 2006

Dilute aqueous solutions of seven diols (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-pentanediol, 2,4-pentanediol, 1,4-pentanediol, and 1,5-pentanediol) were examined by mass spectrometric analysis of the clusters isolated through adiabatic expansion of liquid droplets in vacuum. Stability constants of the solute m-mer hydrate clusters κm (m = 1, 2) were estimated by analyzing the obtained mass spectra. All the stability constants for the diols were found to be approximately equal to or less than 1.0, suggesting that the hydrate clusters of the solute species are as strong as or weaker than those of pure water clusters. Stabilities of the diol hydrate clusters are also dependent on the distance between the two OH groups and/or the number of methylene groups between the two OH groups. From the temperature dependence of the population ratio of the diol-hydrate clusters to pure water ones, we evaluated thermochemical values for the elemental association-dissociation processes.
Short Synthesis of (3S,4R)- and (3R,4R)-3-Hydroxy-4-hydroxymethyl-4-butanolides, Two Lactones from Levoglucosenone
Authors: Matsumoto Katsuya , Ebata Takashi , Koseki Koshi , Okano Koji , Kawakami Hiroshi , Matsushita Hajime
Published: July 2006

Two lactones, (3S,4R)- and (3R,4R)-3-hydroxy-4-hydroxymethyl-4-butanolides, were easily and stereoselectively synthesized in good yield from levoglucosenone (1,6-anhydro-3,4-dideoxy-β-d-glycero-hex-3-enopyranos-2-ulose).
Apparent and Partial Molar Volumes of Some Symmetrical Tetraalkylammonium Perchlorates in 2-Methoxyethanol at 25, 35, and 45 °C
Authors: Das Bijan , Hazra Dilip K
Published: July 2006

The apparent and partial molar volumes (φv) of six symmetrical tetraalkylammonium perchlorates (Me4NClO4 to Hex4NClO4) have been determined in 2-methoxyethanol at 25, 35, and 45 °C. The apparent molar volumes were extrapolated to zero concentration to obtain limiting values at infinite dilution. Ionic limiting partial molar volumes have been estimated using the extrapolation method. The analysis of the data shows that the tetraalkylammonium ions are scarcely solvated and that strong ion–ion interaction exists between the oppositely charged ions in this medium. The temperature dependence of the limiting partial molar volumes have been explained on the basis of ion–solvent interactions.
Synthesis and Characterization of trans[CoCl2(232N4x)]+ (232N4x = 1,4,8,11Tetraazacyclopentadecane, -cyclohexadecane, -cycloheptadecane, -cyclooctadecane, -cyclononadecane, -cycloicosane, -cyclohenicosane, and -cyclotricosane)
Authors: Tsuchimoto Masanobu , Ito Yasuhiro , Fujita Junnosuke
Published: July 2006

Five new macrocyclic ligands which form a large (10—15) chelate ring upon coordination (1,4,8,11-tetraazacyclooctadecane(232N410), -cyclononadecane(232N411), -cycloicosane (232N412), -cyclohenicosane(232N413), and -cyclotricosane(232N415)), and the Co(III) complexes, trans-[CoCl2(232N4x)]+ (x = 7—13, 15) were prepared and characterized. Of six isomers arising from the combination of four chiral nitrogen donor atoms in this type of complex, three and two isomers were obtained, respectively, for complexes with x = 7 and 8, and x = 9—13 and 15. The ligand field parameter of the nitrogen donor atom (Δ(N)) of 232N4x decreases largely from x = 6 to 7, and then shows a small fluctuation with a small decrease at x = even-numbers and a small increase at x = odd-numbers, while a smaller change is observed for the parameter of the chloride ion (Δ(Cl)). The reduction potential for the Co(III)/Co(II) couple (E1/2) shifts to the positive side from the complex with x = 6 to those with x = 7 and 8, and then shows a small change depending on the ring members. The ΔEp(Epa − Epc) values of complexes with x = 8—11 are large, indicating an instability of the medium-sized chelate Co(II) complexes.
Crystal Structures of Cobalt(III)–Methyldiphenylphosphine Complexes. Co(III)–P Bond Lengths and Their Cleavages
Authors: Kashiwabara Kazuo , Kita Masakazu , Masuda Hideki , Kurachi Saeko , Ohba Shigeru
Published: July 2006

The crystal structures of trans-[Co(acac)2(PMePh2)2]PF6 (acac = 2,4-pentanedionate ion) (1), trans-[Co(acac)2(H2O)(PMePh2)]ClO4 (2), and trans(P,P)-[Co(acac)(CN)2(PMePh2)2] (3) were determined by the X-ray diffraction method. Complex 1 crystallizes in the monoclinic, space group P2/n, with two molecules in a unit cell of dimensions a = 17.151(2), b = 10.347(2), c = 10.996(2) Å, β = 107.84(1)°, V = 1857.6(6) Å3. Complex 2 crystallizes in the monoclinic, space group P21/c, with four molecules in a unit cell of dimensions a = 10.161(3), b = 17.291(5), c = 14.938(3) Å, β = 91.76(2)°, V = 2623(1) Å3. Complex 3 crystallizes in the monoclinic, space group C2/c, with four molecules in a unit cell of dimensions a = 21.628(1), b = 8.974(1), c = 16.203(1) Å, β = 106.396(2)°, V = 3012.9(1) Å3. The Co–P bond length for complex 1, 2.329(1) Å, is significantly longer than those for complexes 2 (2.213(1) Å) and 3 (2.2698(4) Å). These lengths are discussed with the hydrolytic properties.
Photodegradation of Humic Substances on MWCNT/Nanotubular-TiO2 Composites
Authors: Zhu Zhiping , Zhou Yi , Yu Hongwen , Nomura Tomoko , Fugetsu Bunshi
Published: July 2006

We report on the first use of MWCNT/nanotubular-TiO2 (multiwalled carbon nanotube, MWCNT; TiO2-derived nanotube, nanotubular-TiO2) composites as catalysts for photodegradation of aquatic humic substances (HSs). The MWCNT was demonstrated to be capable of enhancing the activity of the photocatalyst. The best degradation efficiency was obtained by using MWCNT/nanotubular-TiO2 composites having 20% MWCNTs as the photocatalyst.