bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intermediates in Ammonothermal GaN Crystal Growth under Ammonoacidic Conditions
Authors: Zhang Shiyu , Hintze Frauke , Schnick Wolfgang , Niewa Rainer 
Published: October 2013

AbstractCrystals of two new hexammoniates, namely, [Ga(NH3)6]I3·NH3 and [Ga(NH3)6]Br3·NH3, were grown from liquid ammonia solutions of GaI3 and GaBr3 in a wide temperature range. The known compound [Ga(NH3)5Cl]Cl2 and the new triammoniate of gallium fluoride Ga(NH3)3F3 were obtained ammonothermally during the synthesis of GaN from NH4Cl and NH4F, respectively. The compounds are characterized by crystallographic parameters derived from their X‐ray diffraction data. The crystal structures of all the ammoniates feature octahedrally coordinated Ga atoms in complex ions of the general form [Ga(NH3)6–nXn](3–n)+ (n = 0, 1, 2, 4; X = F, Cl, Br, I). The extensive N–H···X hydrogen bonding networks in these compounds are analyzed. The IR and Raman spectroscopy data for [Ga(NH3)6]X3·NH3 (X = Br, I) and Ga(NH3)2F3 are provided, and the IR spectrum of Ga(NH3)3F3 is compared with those published for the monoammoniate Ga(NH3)F3 and the diammoniate Ga(NH3)2F3. Finally, the thermal deamination features of [Ga(NH3)6]X3·NH3 (X = Br, I) and Ga(NH3)3F3 are also discussed.
An Approach to Rigid, Optically Active Chelate Ligands with C2 Symmetry: Dialkylhexaphosphapentaprismanes
Authors: Höhn Christine , Keller Irene , Rohwer Lars , Heinemann Frank W. , Zenneck Ulrich 
Published: October 2013

AbstractDiastereomeric Pd and Pt complexes with a highly rigid chelate cage ligand core have been designed on the basis of alkylated C2‐symmetric tetra‐tert‐butylhexaphosphapentaprismanes R2P6C4tBu4. The ligands are accessible by substitution of the diiodo derivative I2P6C4tBu4 with Grignard and organyllithium reagents. Depending on the optical properties of the organyl group, racemic or diastereomeric dialkylhexaphosphapentaprismanes R2P6C4tBu4 can be treated with suitable PdII or PtII precursor complexes to form neutral square‐planar cis‐[(R2P6C4tBu4)PdCl2] and cis‐[(R2P6C4tBu4)PtCl2] complexes, respectively. Monoalkylation products RIP6C4tBu4 were also observed in the reaction mixtures, but in most cases were inactive as chelate ligands towards PdII and PtII. For R = (S)‐2‐methylbutyl, the diastereomers of the PdCl2 complex were efficiently separated by column chromatography and crystallization to give the two diastereomers in up to >99 % de and they were fully characterized by NMR and CD spectroscopy as well as by X‐ray diffraction analysis. The two diastereomers of cis‐[{(S)‐2‐methylbutyl}2(P6C4tBu4)PdCl2] represent the first example of a pair of isolated optically active, C2‐symmetric, square‐planar PdII complexes with chelate P–C cage ligands. A square‐planar Pd complex with two monoanionic RP6C4tBu4 cage ligands can be obtained from the monoallylation product (allyl)IP6C4tBu4. This reaction failed for the other monoalkylation products RIP6C4tBu4 and PtII.
Misdescription of edible oils: Flowcharts of analytical choices in a forensic view
Authors: Gallina Toschi Tullia , Bendini Alessandra , Lozano‐Sánchez Jesus , Segura‐Carretero Antonio , Conte Lanfranco 
Published: October 2013

The first commercial differentiation of edible oils, from a technological point of view, distinguishes them as non‐refined (e.g., virgin) and refined, due to the higher commercial value of the former. From this basic quality originates one of the most diffused oils' fraud, the misdeclaration of one or all the phases of the refining process (i). However there are many other ways in which an oil can be misdescribed, such as by: (ii) substituting all or a part of it with a similar but cheaper oil and (iii) declaring a false geographical or botanical origin. The present review addresses the problem of authenticity and misdescriptions of the oils (i–iii) through analytical schemes that can be followed and then used in a forensic view, to provide clues or evidence of fraud. It mentions official methods, known and innovative approaches, from chromatographic or derived methods to spectrometric, spectroscopic, DNA‐based, thermogravimetric, and calorimetric procedures for discriminating genuine from defrauded olive and seed oils.Practical applications: The forensic use of a chemical marker of a fraud, or of an analytical method is questionable if a legal limit or range is not yet defined, or when an official procedure has not been published at least in one State. On the other hand, a validated procedure or evidence can be used for legal purposes when it is possible to demonstrate that the scientific knowledge is more advanced than the existing official methods. In this paper known or promising methods, to discover and prove the most common misdescription of edible oils, which could be useful for a forensic application, are reported and reviewed.
Capsaicinoids, antioxidant activity, and volatile compounds in olive oil flavored with dried chili pepper (Capsicum annuum)
Authors: Caporaso Nicola , Paduano Antonello , Nicoletti Giovanna , Sacchi Raffaele 
Published: October 2013

Spices and herbs are traditionally added to olive oil in Mediterranean gastronomy to enhance its aroma and taste. This paper aims to characterize olive oil aromatized by addition of dried chili pepper (Capsicum annum) (DCP) at different concentrations (10% and 20% by weight) up to 30 days of infusion. Capsaicinoids quantification by HPLC‐DAD, volatile compounds analysis by SPME‐GC–MS and antioxidant activity by ABTS method were performed on chili pepper flavored olive oil (CPOO) in comparison to whole olive oil. At day 7 of infusion, the maximum capsaicinoids content was reached for both the concentrations used and no significant increase was observed for longer infusion times. The volatile headspace composition of CPOOs was influenced by the concentration of DCP added. The addition of DCP caused a significant increase in hexanal, related to oxidation processes. 2‐Methylbutanal, 3‐methylbutanal and 6‐methyl‐5‐hepten‐2‐one were also detected in CPOO and derived from chili as degradation products of the drying process. DCP infusion significantly enriched olive oil with antioxidant compounds and also modified its volatile profile. Capsaicinoids and aroma compounds were rapidly released within the first week of chili infusion in CPOOs, thus suggesting reducing infusion time by optimizing DCP concentration in order to improve CPOO quality and shelf life.Practical applications: The present research is relevant at industrial level for the optimization of olive oil flavoring and the aromatization process. In particular, we defined that the common infusion times of chili, used at industry production for flavoring olive oil, is longer than needed and we suggest reducing infusion time thus also avoiding problems of free acidity and PV increase. Also, we highlighted the importance of quality control for the chili pepper drying procedure and storage time before use, due to the possible formation of off‐flavors in the final product. Moreover, in the present paper a quantification method of the pungent molecules capsaicin and dihydrocapsaicin directly from flavored olive oil was applied. This method could be applied instead of empirical techniques such as Scoville units, for the definition and standardization of the capsaicinoids content in flavored oils and their pungency levels.
Environmentally Benign Lewis Acid Promoted [2+3] Dipolar Cycloaddition Reactions of Nitrile Imines with Alkenes in Water
Authors: Dadiboyena Sureshbabu , Hamme Ashton T. 
Published: October 2013

AbstractMild and environmentally benign Lewis acid promoted 1,3‐dipolar cycloaddition reactions of α‐hydrazonyl chlorides with alkenes in water are reported. In the presence of Lewis acids, these α‐hydrazonyl chlorides generate nitrile imines in situ, which then undergo reaction with a dipolarophile to furnish the corresponding cycloaddition product. In many cases, the required times for the completion of the Lewis acid promoted 1,3‐dipolar cycloaddition reactions in water were comparable to the equivalent reactions performed in an organic solvent. Analogous tetrahexylammonium chloride promoted 1,3‐dipolar cycloaddition reactions were also performed. The comparisons between the reaction times and cycloadduct yields for the aforementioned 1,3‐dipolar reactions in aqueous and organic media and the proposed role of the Lewis acid in the 1,3‐dipolar cycloaddition reaction are described.
Planar Chiral Flavinium Salts: Synthesis and Evaluation of the Effect of Substituents on the Catalytic Efficiency in Enantioselective Sulfoxidation Reactions
Authors: Jurok Radek , Hodačová Jana , Eigner Václav , Dvořáková Hana , Setnička Vladimír , Cibulka Radek 
Published: October 2013

AbstractA series of substituted planar chiral flavinium salts with a phenyl “cap” have been prepared as potential catalysts for enantioselective sulfoxidation reactions with hydrogen peroxide by using an approach based on the synthesis of (arylamino)uracils and their condensation with substituted nitrosobenzenes. The effect of substituents at various positions on the ability of the catalyst to promote enantioselective sulfoxidation recations was investigated. Introduction of the tyrosine group into the side‐chain of the flavinium species or substitution of the nitrogen N‐3 of the flavin unit by o‐isopropylphenyl has a remarkably positive effect on the enantioselectivity of the sulfoxidation reactions of aromatic and aliphatic substrates, respectively. On the other hand, substitution of the phenyl “cap” led to a substantial decrease in the efficiency of the catalyst. In summary, optimisation of the structures of the planar chiral flavinium catalysts led to enantioselectivities of up to 61 % ee for aromatic sulfides and of up to 65 % ee for tert‐butyl methyl sulfide.
Photoactivable Nonsymmetrical Bifunctional Linkers for Protein Immobilization on Attenuated Total Reflectance FTIR Optical Devices
Authors: Hammaecher Catherine , Joris Bernard , Goormaghtigh Erik , Marchand‐Brynaert Jacqueline 
Published: October 2013

AbstractThe photosensitive 4‐azido‐2,3,5,6‐tetrafluoro‐1‐benzoyl core has been connected to maleimide‐, chloroacetyloxy‐, or succinimidyl carbonate motifs through various spacers to furnish a series of bifunctional linkers. One linker (7a) has been used for the construction of a biosensor for β‐lactam antibiotic detection by attenuated total reflectance FTIR (ATR‐FTIR) spectroscopy.
Synthesis and Properties of Carbohydrate‐Based BODIPY‐Functionalised Fluorescent Macrocycles
Authors: Yu Yanhua , Bogliotti Nicolas , Tang Jie , Xie Juan 
Published: October 2013

AbstractCarbohydrate‐based 23‐ to 28‐membered BODIPY‐containing macrocycles have been efficiently synthesised from alkyne‐functionalised BODIPY acid, C‐glucosyl azido amine, and amino acids by employing CuAAC for the macrocyclisation step. BF(OMe) and B(OMe)2 derivatives have also been obtained by treating macrocycle 1 with BCl3 in CH2Cl2 followed by treatment with MeOH. These compounds exhibited similar excellent photophysical properties to those of BODIPY. Investigation of potential receptor properties of the 23‐ and 27‐membered macrocycles 1 and 2 showed that these compounds are sensitive to both anions (F– and CN–) and cations (Cu2+ and Fe3+) in MeCN.
Synthesis and Properties of Azulene‐Substituted Donor–Acceptor Chromophores Connected by Arylamine Cores
Authors: Shoji Taku , Shimomura Erika , Maruyama Mitsuhisa , Maruyama Akifumi , Ito Shunji , Okujima Tetsuo , Toyota Kozo , Morita Noboru 
Published: October 2013

Abstract1‐Ethynylazulenes connected by several arylamine cores reacted with tetracyanoethylene (TCNE) and 7,7,8,8‐tetracyanoquinodimethane (TCNQ) in a formal [2+2] cycloaddition–cycloreversion reaction to afford the corresponding tetracyanobutadiene (TCBD) and dicyanoquinodimethane (DCNQ) chromophores, respectively, in excellent yields. The intramolecular charge‐transfer (ICT) characters between the donor (azulene and arylamine cores) and acceptor (TCBD and DCNQ units) moieties were investigated by UV/Vis spectroscopy and theoretical calculations. The redox behavior of the new TCBD and DCNQ derivatives was examined by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which revealed their multistep electrochemical reduction properties. Moreover, significant color changes were observed by visible spectroscopy under the electrochemical reduction conditions.
Stereoselective Synthesis of Oxa‐Bowls by Nucleophilic Addition to Oxonium Ions: Observation of Nucleophile‐Dependent Hydride Migration
Authors: Gharpure Santosh J. , Porwal Suheel K. 
Published: October 2013

AbstractA simple and reliable platform was developed for the synthesis of symmetrical oxa‐bowls through the Lewis acid mediated etherification of dimethyl acetals. An intramolecular hydride transfer was observed with the use of electron‐rich aryl nucleophiles, which also gave access to unsymmetrical oxa‐bowls.
A General Approach to 1‐Hydroxymethylquinolizidine and 8‐Hydroxymethylindolizidine Stereoisomers: Synthesis of (+)‐Epitashiromine and Formal Syntheses of (+)‐Epilupinine and (+)‐Tashiromine
Authors: Thorat Rakesh G. , Pansare Sunil V. 
Published: October 2013

AbstractA general strategy for the synthesis of structurally and stereochemically related indolizidine and quinolizidine alkaloids was developed. The methodology involves regio‐ and stereoselective 1,3‐dipolar cycloadditions of simple nitrones with ephedrine‐derived alkylidenemorpholinones. The intermediate isoxazolidines can be converted into either the indolizidine or the quinolizidine motif depending on the nitrone and the substituent on the dipolarophile. The approach was applied to the synthesis of (+)‐epitashiromine and to the formal syntheses of (+)‐epilupinine and (+)‐tashiromine.
Metal‐Free Desulfonylation Reaction Through Visible‐Light Photoredox Catalysis
Authors: Yang Deng‐Tao , Meng Qing‐Yuan , Zhong Jian‐Ji , Xiang Ming , Liu Qiang , Wu Li‐Zhu 
Published: October 2013

AbstractThe desulfonylation of β‐arylketosulfones has been achieved in good to excellent yields by using 3‐W blue LEDs light, 1 mol‐% organic dye eosin Y bis(tetrabutylammonium salt) as photocatalyst, and diisopropylethylamine as reducing agent. Mechanistic studies demonstrate that oxidative quenching of the excited eosin Y by β‐arylketosulfones plays a crucial role in the present photoredox catalytic cycle.
Synthesis of Hydroxylated Analogues of α‐Galactosyl Ceramide (KRN7000) with Varying Stereochemistry
Authors: Sawant Ratnnadeep C. , Hung Jung‐Tung , Chuang Huei‐Lin , Lin Huan‐Shuan , Chen Wan‐Shin , Yu Alice L. , Luo Shun‐Yuan 
Published: October 2013

AbstractThe synthesis of analogues of α‐galactosyl ceramide (KRN7000) with an additional hydroxy group in the phytosphingosine chains and with varying stereochemistry is described. Careful selection of glucose, galactose, mannose, and talose hexopyranoses allowed us to control the stereochemistry of some of the hydroxy groups in the sphingosine chain to give some interesting hydroxylated KRN7000 analogues.
Organocatalysis for the Acid‐Free O‐Arylidenation of Carbohydrates
Authors: Geng Yiqun , Faidallah Hassan M. , Albar Hassan A. , Mhkalid Ibrahim A. , Schmidt Richard R. 
Published: October 2013

AbstractMethyl glycopyranosides of glucose, galactose, and mannose, their 2,3‐di‐O‐benzyl‐protected derivatives, as well as the unprotected sugars react with p‐methoxybenzaldehyde dimethyl acetal (3) and with benzaldehyde dimethyl acetal (7) as reagents in the presence of thiourea 1 or squaramide 2 as the organocatalyst to afford regioselectively 4,6‐O‐arylidenated derivatives 5 and 8. With an excess amount of 3 or 7, diarylidenated derivatives are also obtained. In situ formation of acetals of type 3 and 7 from corresponding aldehydes 10 and 13 in the presence of an orthoester and organocatalyst 1 or 2 can be used to generate 5 and 8 directly from the aldehydes. Some substrates also lead to mixed orthoesters with this procedure. The reaction courses are discussed.
Near‐Infrared Photochromic Diarylethenes Based on the Changes in the π‐Conjugated System and the Electronic Properties of the Heteroaryl Moieties
Authors: Cheng Hong‐Bo , Tan Xin , Pang Mei‐Li 
Published: October 2013

AbstractIt is very challenging to construct photochromic materials with absorption and reactivity in the near‐infrared (NIR) spectral region. Herein, four unsymmetrical diarylethene derivatives 1o–4o, which contain both indole and thiophene moieties, have been successfully synthesized, and their photochromic behaviors have been shifted to the NIR region. These newly developed NIR photochromic materials are highly sensitive and responsive to photostimuli both in solution and in poly(methyl methacrylate) films. It has been shown that 1o–4o exhibit remarkable UV/Vis and fluorescence spectral changes, allowing them to behave as reversible optical molecular switches in the NIR region.
Spectral, Conformational and Photochemical Analyses of Photochromic Dithienylethene: cis‐1,2‐Dicyano‐1,2‐bis(2,4,5‐trimethyl‐3‐thienyl)ethene Revisited
Authors: Erko Firealem G. , Berthet Jérôme , Patra Abhijit , Guillot Régis , Nakatani Keitaro , Métivier Rémi , Delbaere Stéphanie 
Published: October 2013

AbstractThe conformational equilibrium and thermodynamic parameters of cis‐1,2‐dicyano‐1,2‐bis(2,4,5‐trimethyl‐3‐thienyl)ethene (1a) and its trans derivative 1c are presented. Irradiation of both compounds was carried out by using 365 nm light, which affects the cis/trans isomerisation process, whereas irradiation with 405 nm light preferentially promotes the formation of the cyclised product. Prolonged irradiation of 1a at 365 nm leads to the formation of a new derivative showing photochromic properties. Evidence for the formation of the novel derivative is presented, and details of its photochromic properties were investigated; a tentative mechanism has also been proposed.
Transition‐Metal‐Free Transformation of Aryl Bromides into Aromatic Esters and Amides via Aryl Trichloromethyl Ketones
Authors: Dohi Souya , Moriyama Katsuhiko , Togo Hideo 
Published: October 2013

AbstractA variety of aryl bromides have been treated with Mg and then chloral, followed by tBuOCl and subsequently alcohols or amines to produce the corresponding aromatic esters or amides in good yields via the formation of aryl trichloromethyl ketones as intermediates. These reactions are examples of a transition‐metal‐free one‐pot preparation of aromatic esters and amides from aryl bromides.
A Biomimetic Approach to the Synthesis of the Core Structure of the Marine Sponge Terpene Halichonadin G
Authors: Saito Kenta , Nishimori Ayumu , Mimura Rika , Nakano Keiji , Kotsuki Hiyoshizo , Masuda Toshiya , Ichikawa Yoshiyasu 
Published: October 2013

AbstractA pathway for the biosynthesis of halichonadin G involving the unique action of ugiase and isocyanide oxidase is proposed. This hypothesis was tested in a biomimetic approach to the synthesis of the core structural unit of this marine sponge terpene, which relies on a key Ugi coupling reaction and an isocyanide‐to‐isocyanate oxidative transformation. The results of this effort demonstrate that the biomimetic strategy can be employed to construct the core structure of halichonadin G in an efficient manner.
Highly Diastereoselective Esterification of Ketenes Generated In Situ from Acyl Chlorides with (R)‐Pantolactone Derivatives
Authors: Yamagami Takafumi , Hatsuda Masanori , Utsugi Masayuki , Kobayashi Ryo , Moritani Yasunori 
Published: October 2013

AbstractOur mechanistic investigations have revealed that Et3N is a key requirement for the highly diastereoselective formation of esters from the corresponding acyl chlorides with (R)‐pantolactone via ketene‐derived complexes. Furthermore, we have discovered that (R)‐N‐benzyl‐pantolactam is a more effective chiral alcohol than (R)‐pantolactone for the esterification of in situ generated ketenes.
Organophosphorus Chemistry without PCl3: A Bridge from Hypophosphorous Acid to H‐Phosphonate Diesters
Authors: Fisher Henry C. , Prost Lucie , Montchamp Jean‐Luc 
Published: October 2013

AbstractA process for the conversion of hypophosphorous acid (H3PO2, HPA) and alcohols into various H‐phosphonate diesters [(RO)2P(O)H] is described. The new reaction provides a missing bridge between HPA and important H‐phosphonates, completely avoiding the use of PCl3. Nickel chloride or nickel on silica catalyze the oxidative phosphorylation of alkyl phosphinates with various alcohols or water. The reaction is atom economic and avoids the formation of waste products. The previous need for both chlorine and base is completely avoided.
Leader performance and prototypicality: Their inter‐relationship and impact on leaders' identity entrepreneurship
Authors: Steffens Niklas K. , Haslam S. Alexander , Ryan Michelle K. , Kessler Thomas 
Published: October 2013

AbstractResearch has demonstrated that leader performance and leader prototypicality are both predictors of leader endorsement. While performance and prototypicality have generally been considered to be independent, this paper suggests that performance and prototypicality are interdependent and have a bi‐directional impact both on each other and on leaders' capacity to engage in identity entrepreneurship (i.e., to define shared group norms and ideals). Two experimental studies indicate that followers infer leaders' prototypicality from their performance and that a leader's prototypicality determines perceptions of performance (indicating reversed causality). Moreover, there is evidence that both performance and prototypicality enhance leaders' capacity to act as identity entrepreneurs. These findings extend our understanding of the mutually dependent causal relationship between followers' perceptions that a leader is ‘one of us’ and that he or she is ‘doing it well’. They also provide the first experimental evidence that these factors are joint determinants of leaders' identity entrepreneurship. Copyright © 2013 John Wiley & Sons, Ltd.
When actions speak volumes: The role of inferences about moral character in outrage over racial bigotry
Authors: Uhlmann Eric Luis , Zhu Luke [Lei] , Diermeier Daniel 
Published: October 2013

AbstractInferences about moral character may often drive outrage over symbolic acts of racial bigotry. Study 1 demonstrates a theoretically predicted dissociation between moral evaluations of an act and the person who carries out the act. Although Americans regarded the private use of a racial slur as a less blameworthy act than physical assault, use of a slur was perceived as a clearer indicator of poor moral character. Study 2 highlights the dynamic interplay between moral judgments of acts and persons, demonstrating that first making person judgments can bias subsequent act judgments. Privately defacing a picture of Martin Luther King, Jr. led to greater moral condemnation of the agent than of the act itself only when the behavior was evaluated first. When Americans first made character judgments, symbolically defacing a picture of the civil rights leader was significantly more likely to be perceived as an immoral act. These studies support a person‐centered account of outrage over bigotry and demonstrate that moral evaluations of acts and persons converge and diverge under theoretically meaningful circumstances. Copyright © 2013 John Wiley & Sons, Ltd.