bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoisomerizable DNA Ligands. Spectral and Electrochemical Properties and Base-Pair Selectivity of Binding of Bis[2-(1-alkylpyridinium-4-yl)vinyl]benzene Dyes
Authors: Juskowiak Bernard , Ohba Mitsuyoshi , Sato Masao , Takenaka Shigeori , Takagi Makoto , Kondo Hiroki 
Published: October 2003

Abstract
A series of bis[2-(alkylpyridinium-4-yl)vinyl]benzene ligands has been prepared and characterized, and their interactions with DNA have been studied by a combination of spectroscopic, hydrodynamic, and biochemical methods. Although bis[2-(1-alkylpyridinium-4-yl)vinyl]benzene ligands interact with DNA by both groove binding and the intercalation mode, the resulting complexes have different binding characteristics, depending on the nature of the DNA. Unexpectedly, nonplanar E,Z isomer also binds to DNA with binding features resembling those of the E,E isomer, though with lower affinity. The interaction of both isomers with a minor groove of [poly(dA-dT)]2 resulted in the formation of more stable complexes compared to the intercalation complexes formed with [poly(dG-dC)]2. Small differences in the binding parameters between planar E,E and non-planar E,Z isomers were explained in terms of an incomplete insertion of a dye molecule in the minor groove (AT polymer) or intercalation pocket (GC polymer), thus allowing trans–cis isomerization of the protruding arm of the molecule to occur without any dramatic changes in the binding affinity of the ligand. The primary redox activity combined with photophysical features of dyes resulted in a photocleavage of supercoiled circular DNA, which occurred at neutral pH under irradiation with visible light, leading mainly to single-strand nicking.
Synthesis of Enantiomerically Enriched 2,5-Dihydrofuran Derivatives from Easily Available Enantiomerically Enriched 2-Butyne-1,4-diols by Stereospecific Transformation
Authors: Saimoto Hiroyuki , Yasui Masaru , Ohrai Shin-ichiro , Oikawa Hiroshige , Yokoyama Kazuhiro , Shigemasa Yoshihiro 
Published: October 2003

Abstract
The transformation of enantiomerically enriched 1,1,4-trisubstituted 4-acyloxy-2-butyn-1-ols 3 into 2,2,5-trisubstituted 3-acyloxy-2,5-dihydrofurans 5 with complete stereospecificity was achieved by an Ag(I)-mediated rearrangement of the monoesters 3 to allenic intermediates 4, followed by Ag(I)-assisted cyclization. A stereochemical analysis revealed that the newly formed carbon–oxygen bond in 5 was formed from the back side of the cleaved carbon–oxygen bond in 3. The propargyl esters 3 were prepared by an enantioselective reduction of the corresponding alkynyl ketones 1, followed by acylation. Since 3-acyloxy-2,5-dihydrofurans 5 were easily converted to the corresponding 4,5-dihydro-3(2H)-furanones 6, this sequence was successfully applied to the synthesis of a differentiation-inducing antibiotic, (S)-(−)-ascofuranone.
Role of the Heteroatoms in the Complex Metal Hydride Reduction of 2-t-Butyl-1,3-dioxan-5-one and 3-Oxoquinolizidine: Comparison of Their Reactivity and Stereochemistry with Those of the Corresponding Carbocyclic Compounds
Authors: Senda Yasuhisa , Sakurai Hiroshi , Itoh Hiroki 
Published: October 2003

Abstract
The complex metal hydride reductions of 2-t-butyl-1,3-dioxan-5-one (1) and 3-oxoquinolizidine (3) are faster than those of the corresponding carbocyclic compounds, 4-t-butylcyclohexanone (2) and trans-2-decalone (4). The stereoselectivities were similar in the LiAlH4 reduction, but the heteracyclohexanones exhibited higher stereoselectivity with NaBH4. These facts are discussed in terms of the intramolecular orbital interaction.
Mass-Spectrometric Study on Ion-Molecule Reactions of CH5+, C2H5+, and C3H5+ with Anilines, Nitrobenzene, and Benzonitrile
Authors: Tsuji Masaharu , Arikawa Takeshi , Nishimura Yukio 
Published: October 2003

Abstract
The gas-phase ion-molecule reactions of CH5+, C2H5+, and C3H5+ with five monosubstituted benzenes carrying a nitrogen atom in the substituent [PhX: X = NH2, NHCH3, N(CH3)2, NO2, CN] have been studied using an ion-trap type of GC/MS at a low chemical-ionization gas pressure of CH4. The major product channels for anilines with low ionization potentials are proton transfer and charge transfer, while the channel for PhNO2 and PhCN with high ionization potentials is proton transfer. The PhX+/(PhX + H)+ ratios increases with decreasing the acidity of the reactant hydrocarbon ion and decreasing the ionization potential of reagent. Small amounts of initial adduct ions, produced by radiative association, and their decomposition products are found in the reactions with C2H5+ and C3H5+. The reaction mechanism is discussed based on product ion distributions and semi-empirical calculations of the energies of intermediates and products.
Reaction of 2-Hydroxybenzaldehydes with Alkynes, Alkenes, or Allenes via Cleavage of the Aldehyde C–H Bond Using a Rhodium Catalyst System
Authors: Kokubo Ken , Matsumasa Kenji , Nishinaka Yuko , Miura Masahiro , Nomura Masakatsu 
Published: October 2003

Abstract
2-Hydroxybenzaldehydes smoothly and efficiently react with various internal and terminal alkynes accompanied by cleavage of the aldehyde C–H bond by using a rhodium-based catalyst system of [RhCl(cod)]2/dppf/Na2CO3 [cod = 1,5-cyclooctadiene; dppf = 1,1′-bis(diphenylphosphino)ferrocene] to give the corresponding 2-alkenoylphenols in good to excellent yields. The regioselectivity of the reaction depends on the substituents of acetylene; an oxygen function on the propargylic position shows a considerable directing effect. The aldehydes can also react with some alkenes or allenes, such as triethylvinylsilane and 2-norbornene or 3-methyl-1,2-butadiene and 1,2-nonadienes, in place of alkynes.
Low-Temperature Oxidation of Methane over Pd Supported on SnO2-Based Oxides
Authors: Widjaja Hardiyanto , Sekizawa Koshi , Eguchi Koichi 
Published: October 2003

Abstract
Pd catalysts supported on various metal oxides were investigated for the low-temperature catalytic combustion of methane. Of the catalysts examined, a Pd/SnO2 catalyst demonstrated excellent activity despite its low specific surface area. The activity of the Pd/SnO2 catalyst was lowered with the addition of M ( = Al, Ce, Fe, Mn, Ni, and Zr) oxide to the support, Pd/SnO2–MOx. It was observed by a transmission electron-microscope observation that the PdO phase was well-dispersed on the outer surface of SnO2support uniformly, observed as an intimately contacted layer on fine SnO2 particles. The temperature-programmed desorption of oxygen has revealed that the catalytic activity depends on the adsorption state of oxygen on palladium. An X-ray photoelectron spectroscopic analysis suggested that reduction of the palladium surface proceeded slowly under a strong palladium-support interaction for Pd/SnO2. In situ X-ray diffraction indicated that the PdO phase was stabilized at higher temperature on SnO2 than on the Al2O3 support. It is considered that the catalytic activity is strongly influenced by the interaction between palladium and SnO2.
Formation of Li-Doped NiO and LiNiO2 in Molten Carbonate
Authors: Iinou Satoshi , Motohira Naobumi , Kamiya Nobuyuki , Ota Ken-ichiro 
Published: October 2003

Abstract
The formations of Li-doped NiO and LiNiO2 in molten carbonate have been studied in CO2–O2 atmospheres from 761 to 1173 K by TGA, color change and XRD. After 24 h of immersion into a Li2CO3 or (Li0.62K0.38)2CO3 melt, the lithiation reaction of NiO was confirmed by both XRD and the color change of a specimen. The rate of the lithiation reaction was very slow, especially in a CO2-rich atmosphere. LiNiO2 was formed in an O2 atmosphere at higher temperatures. The temperature of LiNiO2formation in Li/K carbonate was higher than that in Li2CO3. Oxygen in the atmosphere would have an important role for the formation of LiNiO2 as well as the reaction temperature.
Double Addition of CO2 and CH3OH to Ruthenium Carbonyl Complex with Novel Monodentate Dithiolene
Authors: Sugimoto Hideki , Tsuge Kiyoshi , Tanaka Koji 
Published: October 2003

Abstract
A ruthenium carbonyl complex with unique monodentate SSC2(CN)22− was prepared, while analogous SSC2Ph22− derivative underwent electrophilic and nucleophilic attacks of CO2 and CH3OH to the thiolato and the CO ligands to produce the Ru complex with thio-carboxylic acid and methoxy carbonyl units.
Remarkable Effect of Electron Acceptors on Pyrene-Sensitized Decomposition of N-Phenylglycine
Authors: Ikeda Shingo , Murata Shigeru , Ishii Kunihiko , Hamaguchi Hiro-o 
Published: October 2003

Abstract
The efficiency of the pyrene-sensitized decomposition of N-phenylglycine (NPG) was enhanced by the addition of an electron acceptor, such as p-dicyanobenzene. The reaction mechanism is discussed on the basis of observed Stern-Volmer constants for quenching of singlet excited state of pyrene (py*) and transient absorption spectra. Examination of various electron acceptors shows that the efficient quenching of py* by electron acceptors does not necessarily result in an increase in the NPG decomposition rate.
A New Flux, NaCl, to Grow Layered Perovskite-Type Na2Ca2Nb4O13 Crystals
Authors: Oishi Shuji , Kanoh Masaya , Ishizawa Nobuo 
Published: October 2003

Abstract
Sodium chloride was successfully used as a new flux to grow the layered perovskite-type Na2Ca2Nb4O13 crystals by a slow cooling method. The rectangular thin plate-shaped crystals with sizes up to 1.2 mm × 1.2 mm × 0.03 mm were grown. The obtained crystals were colorless and transparent. The most suitable solute content was 0.4 mol%.
Superiority of the Carbamoylmethyl Ester as an Acyl Donor for the Protease-catalyzed Kinetically Controlled Peptide Synthesis in Organic Media: Application to Segment Condensations
Authors: Miyazawa Toshifumi , Ensatsu Eiichi , Tanaka Kayoko , Yanagihara Ryoji , Yamada Takashi 
Published: October 2003

Abstract
The superiority of the carbamoylmethyl ester as an acyl donor for the α-chymotrypsin-catalyzed kinetically controlled peptide synthesis was demonstrated in several segment condensations carried out in organic media with low water content. Then this approach was successfully applied to the construction of the Leuenkephalin sequence via the 4 + 1 segment condensation.
High Yielding and Practical Synthesis of Rotaxanes by Acylative End-Capping Catalyzed by Tributylphosphine
Authors: Kawasaki Hiroaki , Kihara Nobuhiro , Takata Toshikazu 
Published: October 2003

Abstract
A pseudorotaxane was prepared from dibenzo-24-crown-8 and a dibenzylammonium salt possessing dimethylphenyl and hydroxy groups at the both termini. Acylation of the pseudorotaxane by 3,5-dimethylbenzoic anhydride in the presence of tributylphosphine afforded corresponding rotaxane in 90% yield. Various rotaxanes were readily synthesized in excellent yields by this method.
[VivVvO4(OH)·0.5H2O]n: The First Two-dimensional V-O Layered Cations with Interlamellar Water Molecules and OH− Anion
Authors: Xu Yan , Xu Ji-Qing , Liu Yong-Jiang 
Published: October 2003

Abstract
The new mixed valence layered cluster compound, [VvVivO4(OH)·0.5H2O]n, contains the first two-dimensional V-O cation [VvVivO4]nn+ with water molecules and OH− anions interlayer region, and it’s structure was determinated by crystal X-ray diffraction, EPR and TG analysis.
Carbene-Lithium Interactions
Authors: Arduengo Anthony J , Tamm Matthias , Calabrese Joseph C , Davidson Fredric , Marshall William J 
Published: October 2003

Abstract
The syntheses and characterizations are described for carbene•lithium complexes in which the lithium center is ligated only by carbon atoms. A single crystal X-ray diffraction structure determination on one adduct confirms the coordination environment. The C-Li distance at the carbene center is 215.5 pm. All other coordination to the lithium center originates from a substituted η5-cyclopentadienyl ligand with an average C–Li distance of 225.4 (7) pm.
Synthesis and Electrical Properties of Li1−2xCuxMn2O4
Authors: Tomita Yasumasa , Asai Kazutomo , Kobayashi Kenkichiro 
Published: October 2003

Abstract
Li1−2xCuxMn2O4 (x ≤ 0.10) were synthesized and x dependence of the lattice constant and the electric conductivity were studied. For x ≤ 0.05, Li-O bond length and AC conductivity were decreased by substitution of Cu for Li, and Mn-O bond length was increased with x. Conductivity for x = 0.10 is higher than that for LiMn2O4.
Isolation and Structures of Attenols A and B. Novel Bicyclic Triols from the Chinese Bivalve Pinna attenuata
Authors: Tanaka Noboru , Suenaga Kiyotake , Yamada Kaoru , Zheng Shu-zhen , Chen Hai-sheng , Uemura Daisuke 
Published: October 2003

Abstract
Novel bicyclic triols, attenols A (1) and B (2), were isolated from the Chinese bivalve Pinna attenuata. The absolute stereostructures of 1 and 2 were determined by spectroscopic analysis and the modified Mosher’s method. These attenols exhibited moderate cytotoxicity against P388 cells.
Measurement of Magnetic Susceptibility of a Particle Suspended in a Liquid Phase
Authors: Shinohara Kenji , Hashimoto Kazuhito , Aogaki Ryoichi 
Published: October 2003

Abstract
It was proposed that a method to measure the magnetic susceptibility of a particle such as the biological cell suspended in a liquid phase without any kind of contact with the apparatus. This method utilizes the magnetic force acting on the particle under the high magnetic field gradient, which is balanced by the viscous force controlled by the fluid velocity. The magnetic susceptibility can be determined from the value of the fluid velocity when the suspended particle is stopped against the fluid motion by the magnetic force. An experimental result for a polystyrene micro-sphere proved a possibility of the in vivo assay and separation of the living cells by using this method.
Achievement of Crack-Free BaTiO3 Films over 1 μm in Thickness via Non-Repetitive Dip-Coating
Authors: Kozuka Hiromitsu , Kajimura Masahiro 
Published: October 2003

Abstract
BaTiO3 coating films were prepared from Ba(CH3COO)2-Ti(OC3H7i)4-H2O-CH3COOH-C3H7i OH solutions containing poly(vinylpyrrolidone) with average molecular weight of 630000. Formation of crack-free BaTiO3 films 1.2 μm in thickness was successfully achieved via single-step, non-repetitive dip-coating. The film had relatively dense mocrostructure in SEM scale and transmitted visible light.
Novel Optical Oxygen Pressure Sensing Materials: Platinum Porphyrin-Styrene-Trifluoroethylmethacrylate Copolymer Film
Authors: Amao Yutaka , Asai Keisuke , Miyashita Tokuji , Okura Ichiro 
Published: October 2003

Abstract
Poly(styrene-co-trifluoroethylmethacrylate), (poly-styrene-co-TFEM), is synthesized and applied to the matrix of optical oxygen sensing using phosphorescence quenching of PtOEP by oxygen. Stern-Volmer constant of poly-styrene-co-TFEM film is estimated to be 0.39 Torr−1 (1 Torr =133.322 Pa) indicating that PtOEP-poly-styrene-co-TFEM film is higher sensitive device for oxygen.
A New “Dimer-of-Dimers” Complex Derived from Axial Coordination of 7,7,8,8-Tetracyanoquinodimethane to Ru(II,III) Cation Dimer
Authors: Handa Makoto , Yoshioka Daisuke , Sayama Yasuyoshi , Shiomi Kimie , Mikuriya Masahiro , Hiromitsu Ichiro , Kasuga Kuninobu 
Published: October 2003

Abstract
The “dimer-of-dimers” complex of ruthenium(II,III) pivalate cation dimer [{Ru2(O2CCMe3)4}2(μ-tcnq)(H2O)2](BF4)2 (1) (tcnq=7,7,8,8-tetracyanoquinodimethane) has been prepared and characterized. The X-ray structure analysis of 1 showed that tcnq connects the Ru(II,III) dimers with an Ru-N distance of 2.323(7) Å. The Ru-Ru distance 2.263(1) Å is nearly the same as that of the parent cation dimer [Ru2(O2CCMe3)4]+ (2.260(1) Å). The antiferromagnetic interaction between the Ru(II,III) cores through the tcnq molecule is fairly weak.
Non-Covalent Combinations of Lanthanide(III) Ion and Two DNA Oligomers for Sequence-Selective RNA Scission
Authors: Kuzuya Akinori , Akai Masahiko , Komiyama Makoto 
Published: October 2003

Abstract
By using non-covalent combinations of Lu(III) ion and two DNA oligomers, each of which is complementary with a part of RNA, the RNA is sequence-selectively hydrolyzed. When all the ribonucleotides, except for three consecutive ones, form base-pairs with the DNA oligomers, the selective scission occurs at the 3′-side of the middle of these three non-pairing ribonucleotides.
Chemical Modification of Carbon Hexagonal Plane by Ligand Exchange Reaction of Ferrocene
Authors: Miyake Mikio , Yasuda Koji , Kashihara Takayuki , Teranishi Toshiharu 
Published: October 2003

Abstract
Introduction of the functional groups to the carbon hexagonal plane of the sp2-carbon, which may provide the novel properties to carbon materials, proceeds by the ligand exchange reaction of ferrocene with the sp2-carbon.
Excimer Fluorescence from anti-[2.3](2,7)Phenanthrenophane
Authors: Nakamura Yosuke , Fujii Takahiro , Sugita Sachiko , Nishimura Jun 
Published: October 2003

Abstract
In the [2.3](2,7)phenanthrenophanes prepared by the intramolecular [2 + 2] photocycloaddition of 1,3-bis(7-vinyl-2-phenanthryl)propane, excimer fluorescence was observed for not only syn- but also anti-isomer, though the maximal position of the latter was slightly blue-shifted relative to the former.
Aggregation of DNA-Modified Nanospheres Depending on Added Polynucleotides
Authors: Ihara Toshio , Kurohara Kenta , Jyo Akinori 
Published: October 2003

Abstract
DNA oligomer, dT20 , was immobilized onto the organic nanospheres. The spheres aggregated only in the presence of complementary RNA under a special set of conditions. The aggregation was pseudo-reversible for the temperature change. The techniques of the polynucleotide-directed aggregation should be useful for constructing the structure having mesoscopic dimensions.
N2O Oxidation of Phosphines Catalyzed by Low-Valent Nickel Complexes
Authors: Yamada Tohru , Suzuki Kyosuke , Hashimoto Kentaro , Ikeno Taketo 
Published: October 2003

Abstract
In the presence of a catalytic amount of the nickel(0) complex derived from Ni(acac)2 or NiCl2 with DIBAL or BuLi, nitrous oxide (N2O) was captured and activated to oxidize phosphine(III) into the corresponding phosphine oxide. Bidentate phosphines, for example, 1,3-bis(diphenylphosphino)propane (dppp), were employed as effective ligands for N2O oxidation and were recovered after the reaction.
Mechanism of Thermal Isomerization of Azobenzene in Zeolite Cavities
Authors: Kuriyama Yasunao , Oishi Shigero 
Published: October 2003

Abstract
The life time of cis-azobenzene in zeolite supercage is twenty times longer than that in benzene at room temperature. The kinetic studies indicate that the thermal isomerization proceeds through inversion mechanism. Activation parameters show that the zeolite nanospace gives the same environment as that of gas phase.
Solvents and Molecular Weights of Nitrated Poly(p-phenylene) and Poly(pyridine-2,5-diyl)
Authors: Yamamoto Takakazu , Choi Byoung-Ki , Takeuchi Masataka , Kubota Kenji 
Published: October 2003

Abstract
Poly(p-phenylene), PPP, becomes soluble by nitration and two types of nitrated PPPs give an Mn of 5800 ± 400 in the GPC analysis. Poly(pyridine-2,5-diyl), PPy, has been found to be soluble in hexafluoro-i-propanol, and its GPC analysis gives an Mn and Mw of 6800 and 23000, respectively.
Contribution of Methyls in Retinal Side Chain to Regioselective Photoisomerization of Retinochromes
Authors: Tsujimoto Kazuo , Sugiura Jun’ichirou , Takemori Nobuaki , Mizukami Taku 
Published: October 2003

Abstract
All-trans-9-demethyl-11-methylretinal was synthesized to elucidate the chromophoric interaction between hydrophobic part in retinochrome and 9-methyl substituent of retinal. Photoirradiation of its pigment efficiently gave the 11-cis-isomer in 90% regioselectivity, whereas that of 9-demethylretinochrome provided the 11-cis isomer in 49% selectivity. Structural contribution to regiospecific photoisomerization was proved, in comparison with the other retinochrome analogues, that 9- or 11-methyl substituent is a requisite for highly regioselective photoisomerization, but 13-methyl group is not.
Efficient Electrochemical N-Glycosylation of Silylated Pyrimidines with Protected Arylthioriboses in the Presence of a Catalytic Amount of NBS or Br2
Authors: Nokami Junzo , Osafune Masahiro , Ito Yuichiro , Miyake Fumiaki , Sumida Shin-ichi , Torii Sigeru 
Published: October 2003

Abstract
Electrolysis of silylated pyrimidines with protected arylthioribose, in the presence of a catalytic amount of NBS or Br2 as a mediator in an undivided cell, gave the corresponding N-glycosides (nucleosides) in good yield.
Enantio-Differentiating Hydrogenation of Methyl 2-Furoylacetate and Its Analogs over Tartaric Acid-Modified Raney Nickel
Authors: Nakagawa Satoshi , Haruna Noriko , Acosta Delicia E , Endo Tadateru , Sugimura Takashi , Tai Akira 
Published: October 2003

Abstract
Hydrogenation of methyl 2-furoylacetate over TA-MRNi reduced the three unsaturated bonds to give methyl tetrahydro-2-furoylacetate, the enantiomeric excess (ee) of which at the 3-position was 77%, whereas the 4-position was racemic. Under the same conditions, the substrate of 4-methoxycarbonyl analogue was resulted in hydrogenation of only the ketone moiety to give the corresponding chiral sec-alcohol having a furan ring in 69% ee.
Magnetic-field Induced Orientation of Paraffin
Authors: Kimura Tsunehisa , Yamato Masafumi , Koshimizu Wataru , Kawai Takahiko 
Published: October 2003

Abstract
Paraffin aligns in the magnetic field (9T) during crystallization from melt, forming crystallites oriented with respect to the magnetic field. Discussion is made about the anisotropic structure responsible for the magnetic orientation.
The Facilitated Ion-Transfer of Lauryltrimethyl and Hexadecyltrimethylammonium Cations by Dibenzo Crown Ethers across the Water | 1,2-Dichloroethane Interface
Authors: Bakshi Mandeep Singh , Doe Hidekazu , Sakurada Norio , Arakawa Ryuichi 
Published: October 2003

Abstract
The transfer of lauryltrimethylammonium (LTA+) and hexadecyltrimethyl-ammonium (HTA+) cations facilitated by dibenzo-15-crown-5 (DB15C5), DB18C6 and DB21C7, from aqueous phase to 1,2-dichloroethane (DCE) phase were studied. In the presence of DB15C5, ambiguous wave was observed which became somewhat prominent in the presence of DB18C6 and then irreversible in the presence of DB21C7. Such waves have been attributed to the facilitated transfer of LTA+ and HTA+ cations across the interface in the form of surfactant ion-crown ether (CR) complexes. On the basis of electrospray ionization mass spectroscopy (ESI-MS) measurements, the stoichiometry of such a complex has been proposed to be 1:1. It has also been observed by interfacial tension (γ) measurements that the facilitated transfer becomes irreversible once the immiscible interface is fully occupied by the adsorption of amphiphilic surfactant monomers.
Preparation of Cationic Gold Nanoparticles and Their Monolayer Formation on an Anionic Amphiphile Layer
Authors: Yonezawa Tetsu , Onoue Shin-ya , Kunitake Toyoki 
Published: October 2003

Abstract
Reduction of AuCl4− by sodium borohydride in the presence of quaternary ammonium disulfide gave an aqueous dispersion of cationic gold particles in nano-dimension. These cationic nanoparticles could be assembled effectively on an anionic amphiphile layer with a close-packed structure.
New Bis(salicylaldiminato) Titanium Complexes for Ethylene Polymerization
Authors: Matsui Shigekazu , Tohi Yasushi , Mitani Makoto , Saito Junji , Makio Haruyuki , Tanaka Hidetsugu , Nitabaru Masatoshi , Nakano Takashi , Fujita Terunori 
Published: October 2003

Abstract
New bis(salicylaldiminato) titanium complexes were synthesized and investigated as ethylene polymerization catalysts. These complexes, when activated with methylalumoxane, exhibited one of the highest activities displayed by group 4 transition metal complexes having no cyclopentadienyl ligand(s).