bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ruthenium(IV)–Bis(methallyl) Complexes as UV‐Latent Initiators for Ring‐Opening Metathesis Polymerization
Authors: Wang Dongren , Unold Jörg , Bubrin Martina , Frey Wolfgang , Kaim Wolfgang , Buchmeiser Michael R. 
Published: July 2012

AbstractThe RuIV‐based transition metal catalysts [Ru(η3:η3‐C10H16)Cl2(PPh3)] (1), [Ru(η3:η3‐C10H16)Cl2(PCy3)] (2), and [Ru(η3:η3‐C10H16)(CF3COO)2(PPh3)] (3) have been synthesized and investigated for their use as initiators in the thermally and photo‐initiated ring‐opening metathesis polymerization (photo‐ROMP) of norborn‐2‐ene (NBE). Compounds 1 and 3 display significant photo‐ROMP activity with NBE whereas compound 2, although active in the ROMP of NBE, shows virtually no latency at all. The results are discussed with respect to the structural features of the novel catalysts.
Ordered Mesoporous Carbon Supported Colloidal Pd Nanoparticle Based Model Catalysts for Suzuki Coupling Reactions: Impact of Organic Capping Agents
Authors: Choi Ha Rim , Woo Hyunje , Jang Seongwan , Cheon Jae Young , Kim Chungho , Park Jongnam , Park Kang Hyun , Joo Sang Hoon 
Published: July 2012

AbstractRecent advances in the field of nanoscience have enabled the preparation of high‐surface‐area supported catalysts with precise control over the individual structural components. As such, a range of factors that affect the catalytic reactivity, such as the size, shape, and composition of the nanoparticles (NPs), have been identified. Herein, high‐surface‐area model catalysts that were based on colloidal Pd NPs and a hexagonally ordered mesoporous carbon support were prepared and the impact of various organic capping agents for the Pd NPs on their catalytic activity towards Suzuki coupling reactions was investigated. Colloidal Pd NPs (diameter: 3 nm) were synthesized with different organic capping agents, oleylamine (OA) and trioctylphosphine (TOP), and they were subsequently incorporated into the mesopores of CMK‐3 mesoporous carbon to yield OA‐Pd/CMK‐3 and TOP‐Pd/CMK‐3 nanocatalysts, respectively. The OA‐Pd/CMK‐3 catalyst was treated with acetic acid to generate a supported catalyst with surfactant‐free Pd NPs (OA‐Pd/CMK‐3‐A). Structural characterization revealed that the Pd NPs were uniformly dispersed throughout the mesopores of the CMK‐3 support and the particle size and crystallinity of the Pd NPs were preserved following the incorporation. All of the Pd/CMK‐3 nanocatalysts exhibited higher activity than commercial activated carbon supported Pd catalysts in Suzuki coupling reactions. The catalytic activities of the three Pd/CMK‐3 nanocatalysts were in the following order: OA‐Pd/CMK‐3‐A>OA‐Pd/CMK‐3>TOP‐Pd/CMK‐3. This result suggested that the presence and type of surfactants had a significant effect on the catalytic activity. The OA‐Pd/CMK‐3‐A catalyst also showed high activity for various substrates and good recycling ability in Suzuki coupling reactions.
Study of the Durability of Faceted Pt3Ni Oxygen–Reduction Electrocatalysts
Authors: Wu Jianbo , Yang Hong 
Published: July 2012

AbstractThe durability of truncated octahedral Pt3Ni (t,o‐Pt3Ni) electrocatalysts in the oxygen–reduction reaction (ORR) was investigated by using an accelerated‐durability‐testing procedure. The Pt3Ni/C catalyst lost 21 % of its initial electrochemical surface area (ECSA) and 40 % of the mass‐current density (0.55 to 0.33 A mgPt−1) after 30 000 potential cycles under acidic conditions. In comparison, the reference commercial Pt/C catalyst lost 44 % of its initial ECSA and had a final mass‐specific activity of only 0.09 A mgPt−1 under identical testing conditions. This study shows the potentials of this class of Pt3Ni/C nanostructures as highly active and durable ORR catalysts.
Lithiated Tertiary Carbanions Display Variable Coordination Modes: Evidence from DFT and NMR Studies
Authors: Vincent Mark A. , Campbell Smith Alison , Donnard Morgan , Harford Philip J. , Haywood Joanna , Hillier Ian H. , Clayden Jonathan , Wheatley Andrew E. H. 
Published: July 2012

AbstractDensity functional calculations reveal that, whereas the reaction of 2‐propyl‐N,N‐diisopropylbenzamide (6) with tBuLi in the presence of potentially tridentate donor ligands may result in lateral deprotonation of 6, the behavior of the Lewis base is non‐trivial. The ability of N and O donor centers in the co‐solvent to resist Li+ coordination is found to be synonymous with interaction of lithium with the formally deprotonated carbanion center. Low‐energy structures have been identified whose predicted 1H and 13C NMR spectroscopic shifts are in excellent agreement with experiment. Reaction of 2‐isopropyl‐N,N‐diisopropylbenzamide (5) with tBuLi in the presence of bidentate Lewis base N,N,N′,N′‐tetramethylethylenediamine (TMEDA) yields material that is suggested by NMR spectroscopy to be laterally deprotonated and to have the formulation 5‐Lil⋅TMEDA. In spite of the tertiary aliphatic group at the 2‐position in 5, X‐ray crystallography reveals that the crystalline material isolated from the treatment of 5/(−)‐sparteine with tBuLi is a lateral lithiate in which amide coordination and solvation by bidentate Lewis base results in the Li+ ion interacting with the deprotonated α‐C of the 2‐iPr group (2.483(8) Å). The tertiary carbanion center remains essentially flat and the adjacent aromatic system is highly distorted. The use of a chiral co‐solvent results in two diastereomeric conformers, and their direct observation in solution suggests that interconversion is slow on the NMR timescale.
Phenalenyl‐Based Organozinc Catalysts for Intramolecular Hydroamination Reactions: A Combined Catalytic, Kinetic, and Mechanistic Investigation of the Catalytic Cycle
Authors: Mukherjee Arup , Sen Tamal K. , Ghorai Pradip Kr. , Samuel Prinson P. , Schulzke Carola , Mandal Swadhin K. 
Published: July 2012

AbstractHerein, we report the synthesis and characterization of two organozinc complexes that contain symmetrical phenalenyl (PLY)‐based N,N‐ligands. The reactions of phenalenyl‐based ligands with ZnMe2 led to the formation of organozinc complexes [N(Me),N(Me)‐PLY]ZnMe (1) and [N(iPr),N(iPr)‐PLY]ZnMe (2) under the evolution of methane. Both complexes (1 and 2) were characterized by NMR spectroscopy and elemental analysis. The solid‐state structures of complexes 1 and 2 were determined by single‐crystal X‐ray crystallography. Complexes 1 and 2 were used as catalysts for the intramolecular hydroamination of unactivated primary and secondary aminoalkenes. A combined approach of NMR spectroscopy and DFT calculations was utilized to obtain better insight into the mechanistic features of the zinc‐catalyzed hydroamination reactions. The progress of the catalysis for primary and secondary aminoalkene substrates with catalyst 2 was investigated by detailed kinetic studies, including kinetic isotope effect measurements. These results suggested pseudo‐first‐order kinetics for both primary and secondary aminoalkene activation processes. Eyring and Arrhenius analyses for the cyclization of a model secondary aminoalkene substrate afforded ΔH≠=11.3 kcal mol−1, ΔS≠=−35.75 cal K−1 mol−1, and Ea=11.68 kcal mol−1. Complex 2 exhibited much‐higher catalytic activity than complex 1 under identical reaction conditions. The in situ NMR experiments supported the formation of a catalytically active zinc cation and the DFT calculations showed that more active catalyst 2 generated a more stable cation. The stability of the catalytically active zinc cation was further supported by an in situ recycling procedure, thereby confirming the retention of catalytic activity of compound 2 for successive catalytic cycles. The DFT calculations showed that the preferred pathway for the zinc‐catalyzed hydroamination reactions is alkene activation rather than the alternative amine‐activation pathway. A detailed investigation with DFT methods emphasized that the remarkably higher catalytic efficiency of catalyst 2 originated from its superior stability and the facile formation of its cation compared to that derived from catalyst 1.
Electrochemical and Theoretical Investigations of the Role of the Appended Base on the Reduction of Protons by [Fe2(CO)4(κ2‐PNPR)(μ‐S(CH2)3S] (PNPR={Ph2PCH2}2NR, R=Me, Ph)
Authors: Lounissi Sondes , Zampella Giuseppe , Capon Jean‐François , De Gioia Luca , Matoussi Fatma , Mahfoudhi Sélim , Pétillon François Y. , Schollhammer Philippe , Talarmin Jean 
Published: July 2012

AbstractThe behavior of [Fe2(CO)4(κ2‐PNPR)(μ‐pdt)] (PNPR=(Ph2PCH2)2NR, R=Me (1), Ph (2); pdt=S(CH2)3S) in the presence of acids is investigated experimentally and theoretically (using density functional theory) in order to determine the mechanisms of the proton reduction steps supported by these complexes, and to assess the role of the PNPR appended base in these processes for different redox states of the metal centers. The nature of the R substituent of the nitrogen base does not substantially affect the course of the protonation of the neutral complex by CF3SO3H or CH3SO3H; the cation with a bridging hydride ligand, 1 μH+ (R=Me) or 2 μH+ (R=Ph) is obtained rapidly. Only 1 μH+ can be protonated at the nitrogen atom of the PNP chelate by HBF4⋅Et2O or CF3SO3H, which results in a positive shift of the proton reduction by approximately 0.15 V. The theoretical study demonstrates that in this process, dihydrogen can be released from a η2‐H2 species in the FeIFeII state. When R=Ph, the bridging hydride cation 2 μH+ cannot be protonated at the amine function by HBF4⋅Et2O or CF3SO3H, and protonation at the N atom of the one‐electron reduced analogue is also less favored than that of a S atom of the partially de‐coordinated dithiolate bridge. In this situation, proton reduction occurs at the potential of the bridging hydride cation, 2 μH+. The rate constants of the overall proton reduction processes are small for both complexes 1 and 2 (kobs≈4–7 s−1) because of the slow intramolecular proton migration and H2 release steps identified by the theoretical study.
ChemInform Abstract: An Unprecedented AB2 Tetrahedra Network Structure Type in a High‐Pressure Phase of Phosphorus Oxonitride (PON).
Authors: Baumann Dominik , Sedlmaier Stefan J. , Schnick Wolfgang 
Published: July 2012

AbstractA new high‐pressure polymorph of PON is synthesized by treating PO0.88N1.24H0.56 at around 1350 °C and 12 GPa for 120 min in a Walker‐type module.
ChemInform Abstract: Magnetocaloric Effect in RAl2 (R: Nd, Sm, and Tm): Promising for Cryogenic Refrigeration Close to Liquid Helium Temperature.
Authors: Patra M. , Majumdar S. , Giri S. , Xiao Y. , Chatterji T. 
Published: July 2012

AbstractSingle crystals of NdAl2 and TmAl2 show substantial magnetocaloric effects at their Curie temperatures, which are close to liquid nitrogen and helium temperature, respectively.
ChemInform Abstract: Synthesis, Structure, and Electrochemical Properties of the Layered Sodium Insertion Cathode Material: NaNi1/3Mn1/3Co1/3O2.
Authors: Sathiya M. , Hemalatha K. , Ramesha K. , Tarascon J.‐M. , Prakash A. S. 
Published: July 2012

AbstractThe layered title phase, which is isostructural to NaCoO2, is synthesized by the sol—gel method starting with an aqueous solution of a stoichiometric mixture of Na, Co, Ni, and Mn acetates and citric acid (900 °C, 12 h).
ChemInform Abstract: Carbon—Carbon Bond Formation by Ligand‐Free Cross‐Coupling Reaction Using Palladium Catalyst Supported on Synthetic Adsorbent.
Authors: Monguchi Yasunari , Sakai Keita , Endo Koichi , Fujita Yuki , Niimura Masaru , Yoshimura Masatoshi , Mizusaki Tomoteru , Sawama Yoshinari , Sajiki Hironao 
Published: July 2012

AbstractThe catalyst is used three times in the Suzuki—Miyaura reaction of (Ia) and (II) with a slight loss in activity.
ChemInform Abstract: Iron‐Catalyzed Highly Enantioselective Reduction of Aromatic Ketones with Chiral P2N4‐Type Macrocycles.
Authors: Yu Shenluan , Shen Weiyi , Li Yanyun , Dong Zhenrong , Xu Yaqing , Li Qi , Zhang Juanni , Gao Jingxing 
Published: July 2012

AbstractThe catalytic system in situ generated from the iron carbonyl complex and chiral 22‐membered tetraazadiphospha‐macrocycle PAC exhibits high activity and excellent enantioselectivity in the transfer hydrogenation of various aromatic ketones.
ChemInform Abstract: Catalytic Asymmetric Synthesis of Chromenes and Tetrahydroquinolines via Sequential Allylic Alkylation and Intramolecular Heck Coupling.
Authors: Hornillos Valentin , van Zijl Anthoni W. , Feringa Ben L. 
Published: July 2012

AbstractHighly enantioselective synthesis of title compounds (IV) is achieved by combining asymmetric Cu‐catalyzed allylic substitution with Grignard reagents (II) and intramolecular Heck reaction.
ChemInform Abstract: Silica‐Supported 5‐(Pyrrolidin‐2‐yl)tetrazole: Development of Organocatalytic Processes from Batch to Continuous‐Flow Conditions.
Authors: Bortolini Olga , Caciolli Lorenzo , Cavazzini Alberto , Costa Valentina , Greco Roberto , Massi Alessandro , Pasti Luisa 
Published: July 2012

AbstractA novel immobilized proline mimetic is prepared and tested as a heterogeneous catalyst in α‐amination, Mannich, and Michael reactions under batch conditions.
ChemInform Abstract: Highly Efficient Synthesis of Ureas and Carbamates from Amides by Iodosylbenzene‐Induced Hofmann Rearrangement.
Authors: Liu Peng , Wang Zhiming , Hu Xianming 
Published: July 2012

AbstractThe title method is also applicable to the synthesis of imidazole and oxazole derivatives via an intramolecular rearrangement, and to the synthesis of ureidopeptides from N‐protected amino amides and amino acid esters.
ChemInform Abstract: The Iridium‐Catalyzed Synthesis of Symmetrically and Unsymmetrically Alkylated Diamines under Mild Reaction Conditions.
Authors: Michlik Stefan , Hille Toni , Kempe Rhett 
Published: July 2012

AbstractBenzene‐1,4‐, 1,3,‐ and 1,2‐diamines and antibiotic diamine dapsone (Id) are transformed to the title diamines by reaction with benzylic or aliphatic alcohols.
ChemInform Abstract: Diastereo‐ and Enantioselective Iridium‐Catalyzed Carbonyl Propargylation from the Alcohol or Aldehyde Oxidation Level: 1,3‐Enynes as Allenylmetal Equivalents.
Authors: Geary Laina M. , Woo Sang Kook , Leung Joyce C. , Krische Michael J. 
Published: July 2012

AbstractIn the presence of SEGPHOS catalysts, the reaction proceeds generally with high anti‐selectivity regardless whether alcohols or aldehydes are used.
ChemInform Abstract: A Highly Efficient Palladium‐Catalyzed One‐Pot Synthesis of Unsymmetrical Aryl Alkyl Thioethers under Mild Conditions in Water.
Authors: Wang Liang , Zhou Wei‐You , Chen Sheng‐Chun , He Ming‐Yang , Chen Qun 
Published: July 2012

AbstractThe title reaction of aryl chlorides or bromides with alkyl halides and thiourea as thiol surrogate proceeds at room temperature in many cases.
ChemInform Abstract: Copper‐Catalyzed Oxidative Hydrosulfonylation of Alkynes Using Sodium Sulfinates in Air.
Authors: Taniguchi Nobukazu 
Published: July 2012

AbstractThe reaction proceeds with high syn‐selectivity to afford a broad spectrum of (E)‐alkenyl sulfones from terminal and internal alkynes bearing both alkyl and aryl substituents.
ChemInform Abstract: Regioselective and Stereospecific Cross‐Coupling of Primary Allylic Amines with Boronic Acids and Boronates Through Palladium‐Catalyzed C—N Bond Cleavage.
Authors: Li Man‐Bo , Wang Yong , Tian Shi‐Kai 
Published: July 2012

AbstractThe method is based on the exploiting of the free amino group as an effective leaving group.
ChemInform Abstract: Gold‐Catalyzed Oxidative Cyclizations of cis‐3‐En‐1‐ynes To Form Cyclopentenone Derivatives.
Authors: Bhunia Sabyasachi , Ghorpade Satish , Huple Deepak B. , Liu Rai‐Shung 
Published: July 2012

AbstractVarious indanone and cyclopentenone products are obtained from the corresponding benzene‐ and non‐benzene‐derived substrates.
ChemInform Abstract: A Cobalt‐Catalyzed Domino Route to the ABC Tricyclic Core of Strigolactones and Analogues.
Authors: Le Floch Camille , Laymand Kevin , Le Gall Erwan , Leonel Eric 
Published: July 2012

Abstractortho‐Bromobenzaldehydes or β‐bromo‐α,β‐unsaturated cyclic aldehydes undergo with itaconate (II) a cyclization reaction to give tricyclic cis‐fused cyclopenta[b]furanones as single diastereomers.
ChemInform Abstract: Pd‐Catalyzed Diastereo‐ and Enantioselective [3 + 2]‐Cycloaddition Reaction of Vinyl Epoxide with Nitroalkenes.
Authors: Wu Wen‐Qiong , Ding Chang‐Hua , Hou Xue‐Long 
Published: July 2012

AbstractA convenient protocol employing a chiral ferrocenyl‐based oxazoline ligand is developed which affords highly substituted tetrahydrofurans.
ChemInform Abstract: A New Copper(I)‐Catalyzed Cycloetherification/Acid‐Catalyzed Allylic Nucleophilic Substitution for One‐Pot Synthesis of 2‐Substituted Benzofurans.
Authors: Li Xin , Xue Jijun , Chen Rui , Li Ying 
Published: July 2012

AbstractThe cycloetherification process affords alkylidene‐substituted dihydrobenzofuran structures.
ChemInform Abstract: Benzofurans from Benzophenones and Dimethylacetamide: Copper‐Promoted Cascade Formation of Furan O1—C2 and C2—C3 Bonds under Oxidative Conditions.
Authors: Moure Maria J. , SanMartin Raul , Dominguez Esther 
Published: July 2012

AbstractFor the title synthesis, commercially available or readily synthesized starting materials are used.
ChemInform Abstract: Ruthenium(II)‐Catalyzed Regio‐ and Stereoselective Hydroarylation of Alkynes via Directed C—H Functionalization.
Authors: Hashimoto Yuto , Hirano Koji , Satoh Tetsuya , Kakiuchi Fumitoshi , Miura Masahiro 
Published: July 2012

AbstractStereo‐ and regioselective reaction of various benzamides with internal and terminal alkynes is best achieved under conditions A).
ChemInform Abstract: Regioselective Intramolecular [3 + 2] Annulation of Allene‐Nitrones.
Authors: Inagaki Fuyuhiko , Kobayashi Harumi , Mukai Chisato 
Published: July 2012

AbstractIntramolecular cycloaddition of a variety of in situ generated phenylsulfonyl‐substituted allene‐nitrones proceeds exclusively at the distal double bond to afford fused isoxazoles, irrespective of the substitution pattern at the allene.
ChemInform Abstract: Synthesis and Antimicrobial Evaluation of New Pyrano[4,3‐b]pyran and Pyrano[3,2‐c]chromene Derivatives Bearing a 2‐Thiophenoxyquinoline Nucleus.
Authors: Makawana Jigar A. , Patel Manish P. , Patel Ranjan G. 
Published: July 2012

AbstractEighteen compounds of type (IV) and nine compounds of type (VI) are prepared and evaluated for their antimicrobial activities.
ChemInform Abstract: One‐Pot Preparation of Piperazines by Regioselective Ring‐Opening of Non‐Activated Arylaziridines.
Authors: Trinchera Piera , Musio Biagia , Degennaro Leonardo , Moliterni Anna , Falcicchio Aurelia , Luisi Renzo 
Published: July 2012

AbstractThe method provides a new straightforward approach to cis‐ and trans‐2,5‐disubstituted piperazines.
9‐Benzylidene‐9H‐fluorene Derivatives Linked to Monoaza‐15‐crown‐5: Synthesis and Metal Ion Sensing
Authors: Cao Jing , Li Yang , Feng Junxiang 
Published: July 2012

AbstractTwo kinds of novel styryl chemosensory 2‐FMNC and 3‐FMNC, were designed and synthesized by an apporiate introduction of 9‐benzylidene‐9H‐fluorene group as fluorophore with the aim at avoiding photoisomerisation. These 9‐benzylidene‐9H‐fluorene derivatives showed the similar selectivity and sensitivity upon addition of metal ions. The sensitivity of FMNC to alkaline earth metal ions was Ba2+>Sr2+>Ca2+≈Mg2+.
pH‐Dependent Metal‐Enhanced Fluorescence from CdTe@PAA Nanospheres near the Au Nanoparticles in Aqueous Solution
Authors: Li Rongqing , Wang Chunlei , Xu Shuhong , Wang Zhuyuan , Shao Haibao , Cui Yiping 
Published: July 2012

AbstractMetal‐enhanced fluorescence of semiconductor nanocrystals (NCs) is the current investigation focus. In this work, we directly observed metal‐enhanced fluorescence of CdTe@PAA nanaospheres in aqueous solution. The enhanced magnitude of photoluminescence (PL) was closely related to solution pH values, and the maximal PL enhancement is about 9 times compared with the ones without Au NPs. Furthermore, based on the results of absorptions and fluorescence lifetimes of CdTe@PAA‐Au mixed solution at different pH values, we studied the mechanisms and physics processes of pH‐dependent enhanced PL induced by Au NPs. The pH‐dependent PL of CdTe@PAA‐Au mixed solutions are due to the constantly changing distances between Au NPs and CdTe@PAA nanaospheres with pH. In the CdTe@PAA‐Au mixed solutions, CdTe@PAA nanospheres in close proximity to the Au NPs are exposed to the increased electric fields in between and around the NPs, effectively resulting in significant increases in their absorption cross section. This lends itself to a subsequent increase in the excitation and eventually in the fluorescence emission from the CdTe@PAA nanospheres.
Superior Storage Performance for NO in Modified Natural Mordenite
Authors: Wang Hui , Yu Qinqin , Xiao Liping , Liu Tong , Yu Wanjin , Jiang Xiaoyuan , Zhang Xuming , Zheng Xiaoming 
Published: July 2012

AbstractNatural mordenite (NMOR), modified by acid treatment and ion‐exchange, was employed for NO adsorption in the present study. The NO storage capacity of modified NMOR was greatly improved compared with its original correspondents, mainly due to the preservation of crystalline structure and the improvement of surface area of NMOR. Among all the modified NMOR, Ni‐NMOR exhibited the highest adsorption capacity for NO (1.20 mmol·g−1) in the presence of 10% O2 at 308 K. The influence of the main ingredients in flue gas on the storage capacity of NMOR for NO had also been investigated. In general, H2O, CO2 and SO2 all displayed negative impact on NO adsorption due to their competitive adsorption on the surface of NMOR with NO, while the presence of O2 greatly improved the adsorption of NO because of the formation of NO2 and N2O3. Moreover, Ni‐NMOR exhibited high efficiency for NOx removal through the NOx adsorption‐plasma discharge process.
Preparation of Hierarchical Mesoporous Silica Nanoparticles through a Single‐Templating Approach
Authors: Chen Yuanli , Xiao Min , Zhuang Wei , Li Yi , Li Baozong , Yang Yonggang 
Published: July 2012

AbstractSilicas with hierarchical porous architectures attracted much attention, due to their potential applications in catalysis and separation. Generally, they were prepared through dual‐ or triple‐templating approaches. Herein, mesoporous silica nanoparticles with rod‐like pore channels inside and lamellar mesopores on the surfaces were prepared using the self‐assemblies of a chiral low‐molecular‐weight amphiphile as templates through a single‐templating approach. The formation of the lamellar mesopores was studied by taking field‐emission scanning electron microscopy and transmission electron microscopy images after different reaction times. The lamellar pores were proposed to be formed by merging rod‐like micelles during the sol‐gel process. Moreover, helical nanofibers with rod‐like pore channels inside and lamellar mesopores on the surfaces were prepared with the addition of n‐octanol as a co‐structure‐directing agent.