bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐Throughput Kinetic Study of Hydrogenation over Palladium Nanoparticles: Combination of Reaction and Analysis
Authors: Trapp Oliver , Weber Sven K. , Bauch Sabrina , Bäcker Tobias , Hofstadt Werner , Spliethoff Bernd 
Published: April 2008

AbstractThe hydrogenation of 1‐acetylcyclohexene, cyclohex‐2‐enone, nitrobenzene, and trans‐methylpent‐3‐enoate catalyzed by highly active palladium nanoparticles was studied by high‐throughput on‐column reaction gas chromatography. In these experiments, catalysis and separation of educts and products is integrated by the use of a catalytically active gas chromatographic stationary phase, which allows reaction rate measurements to be efficiently performed by employing reactant libraries. Palladium nanoparticles embedded in a stabilizing polysiloxane matrix serve as catalyst and selective chromatographic stationary phase for these multiphase reactions (gas–liquid–solid) and are coated in fused‐silica capillaries (inner diameter 250 μm) as a thin film of thickness 250 nm. The palladium nanoparticles were prepared by reduction of palladium acetate with hydridomethylsiloxane–dimethylsiloxane copolymer and self‐catalyzed hydrosilylation with methylvinylsiloxane–dimethylsiloxane copolymer to obtain a stabilizing matrix. Diphenylsiloxane–dimethylsiloxane copolymer (GE SE 52) was added to improve film stability over a wide range of compositions. Herein, we show by systematic TEM investigations that the size and morphology (crystalline or amorphous) of the nanoparticles strongly depends on the ratio of the stabilizing polysiloxanes, the conditions to immobilize the stationary phase on the surface of the fused‐silica capillary, and the loading of the palladium precursor. Furthermore, hydrogenations were performed with these catalytically active stationary phases between 60 and 100 °C at various contact times to determine the temperature‐dependent reaction rate constants and to obtain activation parameters and diffusion coefficients.
Is the μ‐Oxo‐μ‐Peroxodiiron Intermediate of a Ribonucleotide Reductase Biomimetic a Possible Oxidant of Epoxidation Reactions?
Authors: de Visser Sam P. 
Published: April 2008

AbstractDensity functional calculations on a μ‐oxo‐μ‐peroxodiiron complex (1) with a tetrapodal ligand BPP (BPP=N,N‐bis(2‐pyridylmethyl)‐3‐aminopropionate) are presented that is a biomimetic of the active site region of ribonucleotide reductase (RNR). We have studied all low‐lying electronic states and show that it has close‐lying broken‐shell singlet and undecaplet (S=0, 5) ground states with essentially two sextet spin iron atoms. In strongly distorted electronic systems in which the two iron atoms have different spin states, the peroxo group moves considerably out of the plane of the μ‐oxodiiron group due to orbital rearrangements. The calculated absorption spectra of 1,111 are in good agreement with experimental studies on biomimetics and RNR enzyme systems. Moreover, vibrational shifts in the spectrum due to 18O2 substitution of the oxygen atoms in the peroxo group follow similar trends as experimental observations. To identify whether the μ‐oxo‐μ‐1,2‐peroxodiiron or the μ‐oxo‐μ‐1,1‐peroxodiiron complexes are able to epoxidize substrates, we studied the reactivity patterns versus propene. Generally, the reactions are stepwise via radical intermediates and proceed by two‐state reactivity patterns on competing singlet and undecaplet spin state surfaces. However, both the μ‐oxo‐μ‐1,2‐peroxodiiron and μ‐oxo‐μ‐1,1‐peroxodiiron complex are sluggish oxidants with high epoxidation barriers. The epoxidation barriers for the μ‐oxo‐μ‐1,1‐peroxodiiron complex are significantly lower than the ones for the μ‐oxo‐μ‐1,2‐peroxodiiron complex but still are too high to be considered for catalytic properties. Thus, theory has ruled out two possible peroxodiiron catalysts as oxidants in RNR enzymes and biomimetics and the quest to find the actual oxidant in the enzyme mechanism continues.
Role of the NH2 Functionality and Solvent in Terdentate CNN Alkoxide Ruthenium Complexes for the Fast Transfer Hydrogenation of Ketones in 2‐Propanol
Authors: Baratta Walter , Ballico Maurizio , Esposito Gennaro , Rigo Pierluigi 
Published: April 2008

AbstractThe reaction of [RuCl(CNN)(dppb)] (1; HCNN=6‐(4‐methylphenyl)‐2‐pyridylmethylamine) with NaOiPr in 2‐propanol/C6D6 affords the alcohol adduct alkoxide [Ru(OiPr)(CNN)(dppb)]⋅n iPrOH (5), containing the RuNH2 linkage. The alkoxide [Ru(OiPr)(CNN)(dppb)] (4) is formed by treatment of the hydride [Ru(H)(CNN)(dppb)] (2) with acetone in C6D6. Complex 5 in 2‐propanol/C6D6 equilibrates quickly with hydride 2 and acetone with an exchange rate of (5.4±0.2) s−1 at 25 °C, higher than that found between 4 and 2 ((2.9±0.4) s−1). This fast process, involving a β‐hydrogen elimination versus ketone insertion into the RuH bond, occurs within a hydrogen‐bonding network favored by the RuNH2 motif. The cationic alcohol complex [Ru(CNN)(dppb)(iPrOH)](BArf4) (6; Arf=3,5‐C6H3(CF3)2), obtained from 1, Na[BArf4], and 2‐propanol, reacts with NaOiPr to afford 5. Complex 5 reacts with either 4,4′‐difluorobenzophenone through hydride 2 or with 4,4′‐difluorobenzhydrol through protonation, affording the alkoxide [Ru{OCH(4‐C6H4F)2}(CNN)(dppb)] (7) in 90 and 85 % yield of the isolated product. The chiral CNN–ruthenium compound [RuCl(CNN){(S,S)‐Skewphos}] (8), obtained by the reaction of [RuCl2(PPh3)3] with (S,S)‐Skewphos and orthometalation of HCNN in the presence of NEt3, is a highly active catalyst for the enantioselective transfer hydrogenation of methylaryl ketones (turnover frequencies (TOFs) of up to 1.4×106 h−1 at reflux were obtained) with up to 89 % ee. Also the ketone CF3CO(4‐C6H4F), containing the strong electron‐withdrawing CF3 group, is reduced to the R alcohol with 64 % ee and a TOF of 1.5×104 h−1. The chiral alkoxide [Ru(OiPr)(CNN){(S,S)‐Skewphos}]⋅n iPrOH (9), obtained from 8 and NaOiPr in the presence of 2‐propanol, reacts with CF3CO(4‐C6H4F) to afford a mixture of the diastereomer alkoxides [Ru{OCH(CF3)(4‐C6H4F)}(CNN){(S,S)‐Skewphos}] (10/11; 74 % yield) with 67 % de. This value is very close to the enantiomeric excess of the alcohol (R)‐CF3CH(OH)(4‐C6H4F) formed in catalysis, thus suggesting that diastereoisomeric alkoxides with the RuNH2 linkage are key species in the catalytic asymmetric transfer hydrogenation reaction.
Serine Hydroxymethyl Transferase from Streptococcus thermophilus and L‐Threonine Aldolase from Escherichia coli as Stereocomplementary Biocatalysts for the Synthesis of β‐Hydroxy‐α,ω‐diamino Acid Derivatives
Authors: Gutierrez Mariana L. , Garrabou Xavier , Agosta Eleonora , Servi Stefano , Parella Teodor , Joglar Jesús , Clapés Pere 
Published: April 2008

AbstractA novel serine hydroxymethyl transferase from Streptococcus thermophilus (SHMT) and a L‐threonine aldolase from Escherichia coli (LTA) were used as stereocomplementary biocatalysts for the aldol addition of glycine to N‐Cbz amino aldehydes and benzyloxyacetaldehyde (Cbz=benzyloxycarbonyl). Both threonine aldolases were classified as low‐specific L‐allo‐threonine aldolases, and by manipulating reaction parameters, such as temperature, glycine concentration, and reaction media, SHMT yielded exclusively L‐erythro diastereomers in 34–60 % conversion, whereas LTA gave L‐threo diastereomers in 30:70 to 16:84 diastereomeric ratios and with 40–68 % conversion to product. SHMT is among the most stereoselective L‐threonine aldolases described. This is due, among other things, to its activity–temperature dependence: at 4 °C SHMT has high synthetic activity but negligible retroaldol activity on L‐threonine. Thus, the kinetic L‐erythro isomer was largely favored and the reactions were virtually irreversible, highly stereoselective, and in turn, gave excellent conversion. It was also found that treatment of the prepared N‐Cbz‐γ‐amino‐β‐hydroxy‐α‐amino acid derivatives with potassium hydroxide (1 m) resulted in the spontaneous formation of 2‐oxazolidinone derivatives of the β‐hydroxyl and γ‐amino groups in quantitative yield. This reaction might be useful for further chemical manipulations of the products.
A One‐Pot Synthesis of Constitutionally Unsymmetrical Rotaxanes Using Sequential CuI‐Catalyzed Azide–Alkyne Cycloadditions
Authors: Spruell Jason M. , Dichtel William R. , Heath James R. , Stoddart J. Fraser 
Published: April 2008

AbstractA one‐pot sequential CuI‐catalyzed azide–alkyne cycloaddition (CuAAC) strategy is presented for the synthesis of constitutionally unsymmetrical cyclobis(paraquat‐p‐phenylene)‐based rotaxanes in good yields from simple starting materials. The methodology consists of performing multiple CuAAC reactions to stopper a pseudorotaxane in a stepwise manner, the order of which is controlled through silyl‐protection and AgI‐catalyzed deprotection of a terminal alkyne. The methodology is highlighted by the synthesis of an amphiphilic branched [4]rotaxane. The methodology increases the ability to access ever more complicated mechanically interlocked compounds to serve in devices as sophisticated and functional molecular machinery.
A General Method for the Rapid Synthesis of Hollow Metallic or Bimetallic Nanoelectrocatalysts with Urchinlike Morphology
Authors: Guo Shaojun , Dong Shaojun , Wang Erkang 
Published: April 2008

AbstractWe have reported a facile and general method for the rapid synthesis of hollow nanostructures with urchinlike morphology. In‐situ produced Ag nanoparticles can be used as sacrificial templates to rapidly synthesize diverse hollow urchinlike metallic or bimetallic (such as Au/Pt) nanostructures. It has been found that heating the solution at 100 °C during the galvanic replacement is very necessary for obtaining urchinlike nanostructures. Through changing the molar ratios of Ag to Pt, the wall thickness of hollow nanospheres can be easily controlled; through changing the diameter of Ag nanoparticles, the size of cavity of hollow nanospheres can be facilely controlled; through changing the morphologies of Ag nanostructures from nanoparticle to nanowire, hollow Pt nanotubes can be easily designed. This one‐pot approach can be extended to synthesize other hollow nanospheres such as Pd, Pd/Pt, Au/Pd, and Au/Pt. The features of this technique are that it is facile, quick, economical, and versatile. Most importantly, the hollow bimetallic nanospheres (Au/Pt and Pd/Pt) obtained here exhibit an area of greater electrochemical activity than other Pt hollow or solid nanospheres. In addition, the ≈6 nm hollow urchinlike Pt nanospheres can achieve a potential of up to 0.57 V for oxygen reduction, which is about 200 mV more positive than that obtained by using a ≈6 nm Pt nanoparticle modified glassy carbon (GC) electrode. Rotating ring‐disk electrode (RRDE) voltammetry demonstrates that ≈6 nm hollow Pt nanospheres can catalyze an almost four‐electron reduction of O2 to H2O in air‐saturated H2SO4 (0.5 M). Finally, compared to the ≈6 nm Pt nanoparticle catalyst, the ≈6 nm hollow urchinlike Pt nanosphere catalyst exhibits a superior electrocatalytic activity toward the methanol oxidation reaction at the same Pt loadings.
ChemInform Abstract: High‐Pressure Polymorphism as a Step Towards Destabilization of LiBH4.
Authors: Filinchuk Yaroslav , Chernyshov Dmitry , Nevidomskyy Andriy , Dmitriev Vladimir 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis, Crystal and Electronic Structure of Li13Ag5Si6, a Potential Anode for Li‐Ion Batteries.
Authors: Lacroix‐Orio Laurence , Tillard Monique , Belin Claude 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A Simple and Novel Route for the Preparation of Chiral Sodium Zincophosphate.
Authors: Liao Sen , Wu Wen‐Wei , Sun Ya‐Bo , Song Bao‐Ling 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A New Approach to Hg1‐xCdxTe: Syntheses, Crystal and Band Structures, and Optical Properties.
Authors: Zou Jian‐Ping , Wang Ming‐Sheng , Wu Ke‐Jun , Guo Guo‐Cong , Li Yan , Zhang Zhang‐Jing , Huang Jin‐Shun 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Facile Synthesis of the Tridecameric Al13 Nanocluster Al13(μ3‐OH)6 (μ2‐OH)18(H2O)24 (NO3)15.
Authors: Gatlin Jason T. , Mensinger Zachary L. , Zakharov Lev N. , MacInnes David , Johnson Darren 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Electrochemical Synthesis of Perovskites in the System K/Ba/Pr/Bi/O.
Authors: Oberndorfer C. P. M. , Konuma M. , Jansen M. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Homologous Silver Bismuth Chalcogenide Halides (N,x)P. Part 3. The (4,x)P, (5,x)P and (7,x)P Structure Families of Modular Compounds with Tunable Composition and Structure.
Authors: Ruck Michael , Poudeu Pierre Ferdinand Poudeu 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Trivalent‐Intermediate Valent Cerium Ordering in Ce2RuZn4.
Authors: Mishra Ratikanta , Hermes Wilfried , Rodewald Ute Ch. , Hoffmann Rolf‐Dieter , Poettgen Rainer 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Diastereoselective Production of Homoallylic Alcohols Bearing Quaternary Centers from γ‐Substituted Allylic Indiums and Ketones.
Authors: Babu Srinivasarao Arulananda , Yasuda Makoto , Baba Akio 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Reliable and General Method for the Cleavage of α‐Arylheteroatom‐Substituted Carboxylic Acids.
Authors: Spurg Anke , Waldvogel Siegfried R. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Novel Rearrangement of 1H‐2,3‐Benzoxazines to Cyclic N‐Acyl Hemiaminals: Application to the Synthesis of 1‐Arylnaphthalene Skeletal Congeners.
Authors: Zheng Xiu Fang , Wang Xiao Lei , Chang Jun Biao , Zhao Kang 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Microwave‐Assisted Kornblum Oxidation of Organic Halides.
Authors: Xu Gang , Wu Jian Ping , Ai Xin Miao , Yang Li Rong 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Activation of DMSO by Phosphonitrilic Chloride: An Efficient Method for Oxidation of Alcohols.
Authors: Pandey Sanjay K. , Bisai Alakesh , Singh Vinod K. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ionene‐Bound Borohydrides: Efficient, Selective, and Versatile Polymer‐Supported Reducing Agents.
Authors: Lakouraj Moslem M. , Tajbakhsh Mahmood , Mahalli Majid S. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of Sterically Hindered 1,3‐Diketones.
Authors: Nandurkar Nitin S. , Bhanushali Mayur J. , Patil Dinkar S. , Bhanage Bhalchandra M. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of N‐Heterocyclic Compounds via Ene—yne Metathesis Reactions.
Authors: Groaz Elisabetta , Banti Donatella , North Michael 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Alkyl Alk‐1‐enyl Alanes in Reissert‐Like Reaction.
Authors: Signore G. , Malanga C. , Menicagli R. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ultrasound‐Promoted Rapid Oxidative Cleavage Oximes with NaBrO3/Ion Exchange Resin.
Authors: Shaabani Ahmad , Rahmati Abbas , Naderi Soheila 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Reactions of Lithium Silylcuprates with Pyrazolium and Indazolium Salts.
Authors: Gonzalez‐Nogal Ana M. , Calle Mariola , Cuadrado Purificacion 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Convergent and Stereospecific Synthesis of Molecules Containing α‐Functionalized Guanidiniums via α‐Guanidino Acids.
Authors: Balakrishnan Shalini , Zhao Chen , Zondlo Neal J. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: An Efficient Catalytic Protocol for the Pauson—Khand Reaction.
Authors: Blanco‐Urgoiti Jaime , Abdi Delbrin , Dominguez Gema , Perez‐Castells Javier 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis of Polysubstituted Cyclopentenones via [4 + 1] Reactions of TIPS‐Vinylketenes.
Authors: Li Zhi , Moser William H. , Deng Ruixue , Sun Liangdong 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: 4‐Hydroxy‐2‐quinolones. Part 125. Ethyl 3‐Bromo‐2,4‐dioxo‐1,2,3,4‐tetrahydroquinoline‐3‐carboxylates as Potential Brominating Agents.
Authors: Ukrainets I. V. , Sidorenko L. V. , Golovchenko O. S. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Allylation and Vinylation of Aryl Radicals Generated from Diazonium Salts.
Authors: Heinrich Markus R. , Blank Olga , Ullrich Daniela , Kirschstein Marcel 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Palladium‐Catalyzed Decarboxylative sp3—sp3 Coupling of Nitrobenzene Acetic Esters.
Authors: Waetzig Shelli R. , Tunge Jon A. 
Published: April 2008

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.