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We present evidence for iconicity as the motivation for two patterns of morphophonological alternation in Nigerian Pidgin, also known as Naijá. To express an ‘unconventional positive’ in all varieties of Naijá, some nouns with the tone melodies H-L and L-H surface with the tone melodies L-H and H-L, respectively. In addition to unconventional positive, the Wafi variety of Naijá also expresses ‘unconventional negative.’ In this case, the first syllable of bisyllabic nouns (analogously, the first foot of four-syllable nouns) is transposed with the second syllable. However, in onsetful monosyllabic nouns, the initial consonant is deleted to express an unconventional negative. We account for the metatheses and truncation using transderivational faithfulness constraints and other independent constraints. Expressing the notion of unconventionality by changing the prosaic linear order of phonological elements in a word is a kind of form-meaning resemblance. Similarly, the association of (unconventional) negative with a reduction in a string of segments is another pattern of iconicity. This suggests that crossmodal depiction of sensory imagery, in addition to articulatory and auditory factors, can motivate morphophonological patterns. The morphophonological metatheses and truncation in Naijá contribute to the typology of morphophonological alternations with iconicity as their motivation. Most importantly, these patterns run counter to the claim that pidgins and creoles have simplified morphophonology.

In this study, the production of propylene from 2-butene and 1-butene via the metathesis process was investigated and simulated. The effects of operational parameters, including reactor temperature, residence time, and 1-butene/2-butene molar ratio, on reactor performance were examined, and statistical models were developed. The design of experiment (DoE) was performed using the response surface methodology (RSM)-central composite design (CCD) approach for efficient experimentation and model development as well as optimization. The study's findings indicate a high conversion rate for 2-butene. By statistically analyzing the obtained data and performing analysis of variance (ANOVA), the influential parameters and their degree of importance were determined. Sensitivity analysis was conducted based on the developed models. Finally, using these models and desirability function as a powerful optimization algorithm, optimal conditions for the process were obtained. The results of the optimization showed that the maximum propylene molar fraction (32.5 %) was obtained at a temperature of 508.4 °C, a residence time of 20.7 s, and a 1-butene/2-butene molar ratio of 0.1.

Isomerization Metathesis (ISOMET) reaction is an emerging tool for "open loop" chemical recycling of polyethylene to propylene. Novel, latent N‐Alkyl substituted Cyclic(Alkyl)(Amino)Carbene (CAAC)–ruthenium catalysts (5a‐Ru, 3b‐Ru – 6c‐Ru) are developed rendering "inverted" chemical structure while showing enhanced ISOMET activity in combination with (RuHCl)(CO)(PPh3)3 (RuH) double bond isomerization co‐catalyst. Systematic investigations reveal that the steric hindrance of the substituents on nitrogen and carbon atom adjacent to carbene moiety in the CAAC ligand have significantly improved the catalytic activity and robustness. In contrast to the NHC‐Ru and CAAC‐Ru catalyst systems known so far, these systems show higher isomerization metathesis (ISOMET) activity (TON: 7400) on the model compound 1‐octadecene at as low as 3.0 bar optimized pressure, using technical grade (3.0) ethylene. The propylene content formed in the gas phase can reach up to 20% by volume. [ABSTRACT FROM AUTHOR]

Abstract Isomerization Metathesis (ISOMET) reaction is an emerging tool for “open loop” chemical recycling of polyethylene to propylene. Novel, latent N‐Alkyl substituted Cyclic(Alkyl)(Amino)Carbene (CAAC)–ruthenium catalysts (5a‐Ru, 3b‐Ru – 6c‐Ru) are developed rendering “inverted” chemical structure while showing enhanced ISOMET activity in combination with (RuHCl)(CO)(PPh3)3 (RuH) double bond isomerization co‐catalyst. Systematic investigations reveal that the steric hindrance of the substituents on nitrogen and carbon atom adjacent to carbene moiety in the CAAC ligand have significantly improved the catalytic activity and robustness. In contrast to the NHC‐Ru and CAAC‐Ru catalyst systems known so far, these systems show higher isomerization metathesis (ISOMET) activity (TON: 7400) on the model compound 1‐octadecene at as low as 3.0 bar optimized pressure, using technical grade (3.0) ethylene. The propylene content formed in the gas phase can reach up to 20% by volume.

Covalent organic frameworks (COFs) offer vast structural and chemical diversity enabling a wide and growing range of applications. While COFs are well-established as heterogeneous catalysts, so far, their high and ordered porosity has scarcely been utilized to its full potential when it comes to spatially confined reactions in COF pores to alter the outcome of reactions. Here, we present a highly porous and crystalline, large-pore COF as catalytic support in α,ω-diene ring-closing metathesis reactions, leading to increased macrocyclization selectivity. COF pore-wall modification by immobilization of a Grubbs-Hoveyda-type catalyst via a mild silylation reaction provides a molecularly precise heterogeneous olefin metathesis catalyst. An increased macro(mono)cyclization (MMC) selectivity over oligomerization (O) for the heterogeneous COF-catalyst (MMC:O=1.35) of up to 51 % compared to the homogeneous catalyst (MMC:O=0.90) was observed along with a substrate-size dependency in selectivity, pointing to diffusion limitations induced by the pore confinement.

The use of template molecules as chemical scaffolds that significantly influence the course of the reaction has recently been intensively studied. Peptide nucleic acids (PNA) are molecules that mimic natural nucleic acids. They are a promising matrix in such reactions because they possess high affinity and specificity in their interactions. The manner of PNA interaction is predictable based on sequence complementarity. Recently, we report the visible light-induced metathesis reaction in peptides containing a diselenide bond. Herein, we present an efficient and straightforward method of the visible light-driven diselenide-based metathesis of peptide–nucleic acid conjugates. Compared to a similar photochemical transformation in peptides, a significant increase in the metathesis efficiency was obtained due to the template effect. [ABSTRACT FROM AUTHOR]

3,3′,5,5′-Tetra-tert-butyl-2′-sulfanyl[1,1′-biphenyl]-2-ol (H2[tBu4OS]) was prepared in 24 % yield overall from the analogous biphenol using standard techniques. Addition of H2[tBu4OS] to Mo(NAr)(CHCMe2Ph)(2,5-dimethylpyrrolide)2 led to formation of Mo(NAr)(CHCMe2Ph)[tBu4OS], which was trapped with PMe3 to give Mo(NAr)(CHCMe2Ph)[tBu4OS](PMe3) (1(PMe3)). An X-ray crystallographic study of 1(PMe3) revealed that two structurally distinct square pyramidal molecules are present in which the alkylidene ligand occupies the apical position in each. Both 1(PMe3)A and 1(PMe3)B are disordered. Mo(NAd)(CHCMe2Ph)(tBu4OS)(PMe3) (2(PMe3); Ad=1-adamantyl) and W(NAr)(CHCMe2Ph)(tBu4OS)(PMe3) (3(PMe3)) were prepared using analogous approaches. 1(PMe3) reacts with ethylene (1 atm) in benzene within 45 minutes to give an ethylene complex Mo(NAr)(tBu4OS)(C2H4) (4) that is isolable and relatively stable toward loss of ethylene below 60 °C. An X-ray study shows that the bond distances and angles for the ethylene ligand in 4 are like those found for bisalkoxide ethylene complexes of the same general type. Complex 1(PMe3) in the presence of one equivalent of B(C6F5)3 catalyzes the homocoupling of 1-decene, allyltrimethylsilane, and allylboronic acid pinacol ester at ambient temperature. 1(PMe3), 2(PMe3), and 3(PMe3) all catalyze the ROMP of rac-endo,exo-5,6-dicarbomethoxynorbornene (rac-DCMNBE) in the presence of B(C6F5)3, but the polyDCMNBE that is formed has a random structure.

In the course of this work, fl uorinated catalysts MoO3 /Al2 O3 -F for the olefi ns metathesis have been synthesized. The materials have been characterized by various physicochemical methods and tested in the propylene metathesis reaction. It has been shown that the support fl uorination leads to partial replacement of surface hydroxyl groups by F, which is accompanied by an increase in the strength of both Lewis acid sites and residual bridging OH groups. Increasing the fl uorine content on γ-Al2O3 up to 3 wt. % leads to an increase in the conversion of propylene in the metathesis reaction by 1.5 times (WHSV = 1.1 h-1, Т = 100 °С, р = 9 atm.) with a selectivity of more than 95%. However, when the reaction is carried out at atmospheric pressure, fl uorinated samples show lower activity than unpromoted ones. The results of this work show that the support acidity plays an important role in propylene metathesis. The proposed method of catalyst modifi cation opens up new possibilities for improving classical metathesis catalysts.

A number of alkali organometallic complexes with suitable thermodynamic properties and high capacity for hydrogen storage have been synthesized; however, few transition metal–organic complexes have been reported for hydrogen storage. Moreover, the synthetic processes of these transition metal–organic complexes via metathesis were not well characterized previously, leading to a lack of understanding of the metathesis reaction. In the present study, yttrium phenoxide and lanthanum phenoxide were synthesized via metathesis of sodium phenoxide with YCl3 and LaCl3, respectively. Quasi in situ NMR, UV-vis, and theoretical calculations were employed to characterize the synthetic processes and the final products. It is revealed that the electron densities of phenoxides in rare-earth phenoxides are lower than in sodium phenoxide due to the stronger Lewis acidity of Y3+ and La3+. The synthetic process may follow a pathway of stepwise formation of dichloride, monochloride, and chloride-free species. Significant decreases in K-band and R-band absorption were observed in UV-vis, which may be due to the weakened conjugation effect between O and the aromatic ring after rare-earth metal substitution. Two molecular structures, i.e., planar and nonplanar, are identified by theoretical calculations for each rare-earth phenoxide. Since these two structures have very close single-point energies, they may coexist in the materials. [ABSTRACT FROM AUTHOR]

This research report presents a quantitative investigation into the impact of social variables including age, education and gender on a specific phonological variation (Metathesis in word [tʃoklæ]) in the Hawrami language, specifically the Paveh dialect. The study examines a group of 60 individuals (30 men and 30 women) across four different age groups, utilizing the variationist sociolinguistics framework. Data collected from the main group is compared to data gathered from a standard group of illiterate men and women over 60 years of age. The study focuses on metathesis of the word [tʃoklæ], which exhibits the most differences between the standard and main groups. The research findings indicate a significant relationship between age and gender variables and the phonological diversity under study. The level of education, however, does not show a significant relationship with the occurrence of the metathesis process in the word [tʃoklæ], as the rate of significance of the relationship is greater than 0.5 (α=0.683). Additionally, the results demonstrate that gender has a greater impact on the metathesis process in the word [tʃoklæ] than age. [ABSTRACT FROM AUTHOR]

This paper describes aspects of the phonology of Kodi, an Austronesian language of Sumba, Indonesia. Based on the analysis of recordings of an elicited word list, the description covers the segmental phonology, syllable structure, stress and the spreading of palatalization and labialization features. A pervasive feature of Kodi is a number of morphophonological processes that result in most words alternating between a longer and shorter form. These include antepenultimate vowel reduction, paragoge and apocope, as well as productive synchronic metathesis of a word-final vowel and the preceding consonant. When a word with identical vowel qualities in the two final syllables undergoes metathesis, it results in a double vowel. By measuring hundreds of vowel lengths in our data, we show that double vowels are phonetically distinct in length from stress-induced vowel lengthening in Kodi.

This study presents an analysis of synchronic metathesis in the Saraiki language based on the Optimality Theory (OT) approach. It is limited to the voiced laryngeal fricative (/ɦ/). Only voiced phonemes are the targets of /ɦ/ metathesis in Saraiki (resulting in breathy voiced consonants), while voiceless plosives are incompatible with this process. Metathesized and non-metathesized forms both occur in Saraiki. They are realized in informal and formal speech styles, respectively. This study analyses the informal speech style and identifies the reasons behind the movement of the above laryngeal fricative in phonetic optimization.

The olefin metathesis reaction has found numerous applications in organic synthesis. This is due to a number of advantages, such as the tolerance of most functional groups and sterically demanding olefins. This article reviews recent advances in the application of the metathesis reaction, particularly the metathetic cyclization of dienes and enynes, in synthesis protocols leading to (hetero)aromatic compounds. [ABSTRACT FROM AUTHOR]

Development of more sustainable and environmentally friendly polymers as alternatives to petroleum‐based polymers is a priority. We report the synthesis of six linear, aliphatic, renewable polymers by acyclic diene metathesis (ADMET) and thiol‐ene polymerization of α,ω‐polyenes resulting from thermal esterification of adipic, azelaic, and itaconic acids with 9‐decen‐1‐ol. ADMET homopolymerization was performed with 1.0 mol% Hoveyda–Grubbs second generation metathesis catalyst. Thiol‐ene copolymerization was conducted photochemically with 1 wt% 2,2‐dimethoxy‐2‐phenyl‐acetophenone and stoichiometric 1,2‐ethanedithiol (EDT). Although the thiol‐ene copolymers exhibited carbon and atom economies of 100%, the ADMET‐derived polyesters possessed superior renewable carbon content (100%) and environmental factors (<4). These results were attributed to incorporation of non‐renewable EDT into poly(thioether‐ester)s and loss of ethene during production of ADMET polyesters. The Mn (>26 kDa), Mw (>92 kDa), and dispersities (>3.4) of the poly(thioether‐ester)s were higher than the corresponding polyesters, which in part explained why the poly(thioether‐ester)s gave higher melting (>61°C), crystallization (>49°C) and glass transition (>−31°C) temperatures. The cross‐linked itaconate polymers did not melt or crystallize, thereby suggesting amorphous morphology. Lastly, the ADMET polyesters were more thermally stable (T50 > 408°C) than the poly(thioether‐ester)s (T50 < 377°C). In summary, the aliphatic biopolymers displayed a wide range of properties that were impacted by polymerization method as well as the nature of the monomer. [ABSTRACT FROM AUTHOR]

Isoflav-3-enes with natural substitution patterns were prepared in two steps from readily available starting materials by means of a one-pot Wittig methylenation -- etherification -- Wittig methylenation, followed by ring-closing metathesis catalyzed by the Grubbs second generation catalyst. This included the preparation of a series of five novel 1-[(2-phenylallyl)oxy]-2-vinylbenzenes in good yields (61 -- 89%). Olefin metathesis thus affords a common strategy for the synthesis of all three flavonoid subclasses, i.e. the flavonoids, neoflavonoids and isoflavonoids. [ABSTRACT FROM AUTHOR]

This article discusses the distribution of rhotic and non-rhotic English in the United States between 1770 and 1849. For the study, handwritten documents belonging to individuals from different social classes were inspected to identify misspellings that deviated from conventional spelling patterns (if compared to dictionaries and spellers of the time) regarding or the previous vowel. The investigation shows that during the period elision was never the most frequent occurrence. In fact, the results indicate that it was the quality of the previous vowel that underwent significant oscillations. Regarding the distribution of rhotic and non-rhotic English in the United States, the evidence suggests that r-lessness happened mostly in states that are predominantly non-rhotic today. In terms of social variation, there was a tendency for the middle classes to produce more non-rhotic misspellings than other classes. Lastly, the data indicates a strong possibility of a rapid expansion of non-rhotic English after 1850. [ABSTRACT FROM AUTHOR]

Copyright of Athar alrafedain is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, two types of Rare Earth (RE) 3-furoate complexes were synthesized by metathesis reactions between RE chlorides or nitrates and preformed sodium 3-furoate. Two different structural motifs were identified as Type 1RE and Type 2RE. The Type 1RE monometallic complexes form 2D polymeric networks with the composition [RE(3fur)3(H2O)2]n (1RE = 1La, 1Ce, 1Pr, 1Nd, 1Gd, 1Dy, 1Ho, 1Y; 3furH = 3-furoic acid) while Type 2RE bimetallic complexes form 3D polymeric systems [NaRE(3fur)4]n (2RE = 2Ho, 2Y, 2Er, 2Yb, 2Lu). The stoichiometric mole ratio used (RE: Na(3fur) = 1:3 or 1:4) in the metathesis reaction determines whether 1RE or 2RE (RE = Ho or Y) is formed, but 2RE (RE = Er, Yb, Lu) were obtained regardless of the ratio. The corrosion inhibition behaviour of the compounds has been examined using immersion studies and electrochemical measurements on AS1020 mild steel surfaces by a 0.01 M NaCl medium. Immersion test results revealed that [Y(3fur)3(H2O)2]n has the highest corrosion inhibition capability with 90% resistance after 168 h of immersion. Potentiodynamic polarisation (PP) measurements also indicate the dominant behaviour of the 1Y compound, and the PP curves show that these rare earth carboxylate compounds act predominantly as anodic inhibitors. [ABSTRACT FROM AUTHOR]

The use of template molecules as chemical scaffolds that significantly influence the course of the reaction has recently been intensively studied. Peptide nucleic acids (PNA) are molecules that mimic natural nucleic acids. They are a promising matrix in such reactions because they possess high affinity and specificity in their interactions. The manner of PNA interaction is predictable based on sequence complementarity. Recently, we report the visible light-induced metathesis reaction in peptides containing a diselenide bond. Herein, we present an efficient and straightforward method of the visible light-driven diselenide-based metathesis of peptide–nucleic acid conjugates. Compared to a similar photochemical transformation in peptides, a significant increase in the metathesis efficiency was obtained due to the template effect.

Stereoselective control of the cross metathesis of olefins is highly desired in synthetic procedures. In this work, guided by thermodynamic and kinetic descriptors calculated using density functional theory methods, we performed an exhaustive exploration of the stereoselectivity of the cross metathesis of allylbenzene and 2-butene-1,4-diyl diacetate, catalyzed by a second-generation Grubbs catalyst. The kinetics of all possible propagation routes resulted in an E/Z 5:1 distribution of the metathesis product, in agreement with the experimental value of 7:1. Structural strain of olefins and activated catalyst was evaluated to reveal insights into the design of stereoselective catalysts within a strain-driven approach.

The phase complex of a ternary reciprocal system of lithium and rubidium bromides and chromates has been studied theoretically and experimentally for the first time. We have divided the phase complex into secondary phase compatibility triangles and obtained a linear phase tree, in which the vertices of each simplex describe crystallizing phases. Using the ion balance method, we have described chemical transformations and predicted crystallizing phases for mixtures with a preset composition. Using data for the bounding systems, we have constructed a computer 3D model of the phase complex and obtained polythermal and isothermal sections and liquidus surface isotherms. Using differential thermal analysis and X-ray diffraction, we have demonstrated adequacy of the proposed division into simplexes. Phase equilibria in the system have been studied experimentally, and we have determined the composition and melting point of ternary invariant points. The composition of the ternary eutectic E3 245 is recommended for use as a fusible electrolyte for electrochemical cells. Comparison of experimental data with prediction results derived from the model demonstrates adequacy of modeling of phase equilibria with the use of a 3D model. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metathesis is a commercially successful process for the production of lower olefins. • An increase of the F content on support leads to significant increase of the propylene conversion. • The change in the support acidity doesn't affect the structure of surface molybdenum forms. • Olefin metathesis can proceed under mild conditions on modified catalysts. • The strength of OH groups and Lewis acidity are the determining factors for propylene metathesis. Supported MoO 3 /Al 2 O 3 -F catalysts were synthesized and characterized by Raman, IR, and NMR spectroscopy. It was shown that support fluorination leads to partial substitution of surface OH groups with F which is accompanied by increases the strength of both LAS (Lewis Acid Sites) and residual bridging OH groups. But the change in the acidity doesn't affect the structure of surface molybdenum forms. An increase of the fluorine content on γ-Al 2 O 3 up to 6 wt% leads to 4.7-fold increase of the propylene conversion in metathesis reaction (WHSV = 11 h−1, T = 100 °C, p = 9 atm.) with selectivity above 95 %. The results prove that the support acidity plays an important role in the propylene metathesis. The catalyst modification method proposed here opens new opportunities for the improvement of classical metathesis catalysts. [ABSTRACT FROM AUTHOR]

The phase complex of a ternary reciprocal system of lithium and rubidium bromides and chromates has been studied theoretically and experimentally for the first time. We have divided the phase complex into secondary phase compatibility triangles and obtained a linear phase tree, in which the vertices of each simplex describe crystallizing phases. Using the ion balance method, we have described chemical transformations and predicted crystallizing phases for mixtures with a preset composition. Using data for the bounding systems, we have constructed a computer 3D model of the phase complex and obtained polythermal and isothermal sections and liquidus surface isotherms. Using differential thermal analysis and X-ray diffraction, we have demonstrated adequacy of the proposed division into simplexes. Phase equilibria in the system have been studied experimentally, and we have determined the composition and melting point of ternary invariant points. The composition of the ternary eutectic E3 245 is recommended for use as a fusible electrolyte for electrochemical cells. Comparison of experimental data with prediction results derived from the model demonstrates adequacy of modeling of phase equilibria with the use of a 3D model. [ABSTRACT FROM AUTHOR]

The [Ru(PPh3)2Cl-piperidine(4-aminomethyl)] complex (mono-Ru) was synthesized from [Ru(PPh3)3Cl2] and 4-(aminomethyl)piperidine, whereas the [(PPh3)PdCl(Shiff-pip)] complex (mono-Pd) was obtained by reacting [Pd(PPh3)2Cl2] with its respective Schiff base ligand, both at a 1:1 molar ratio. The heterobimetallic [RuCl2(PPh3)2](μ-Schiff)Pd(PPh3)Cl] complex (Ru/Pd) was synthesized via a one-pot, three-component reaction of mono-Ru, [(Pd(PPh3)2Cl2] and salicylaldehyde. All complexes were fully characterized by FTIR, UV-Vis, and NMR spectroscopy, as well as elemental analysis, MALDI-TOF mass spectrometry, cyclic voltammetry, and computational studies. Ru/Pd was able to polymerize norbornene (NBE) by two different mechanisms: ROMP and vinyl polymerization. The Ru fragment was active for ROMP of NBE, reaching yields of 68 and 31% for mono-Ru and Ru/Pd, respectively, when the [NBE]/[Ru] = 3000 molar ratio and 5 μL EDA addition were employed at 50 °C. The poly(norbornene) (polyNBE) obtained presented an order of magnitude of 104 g mol−1 and Ð values between 1.48 and 1.79. For the vinyl polymerization of NBE, the Pd fragment was active using MAO as a cocatalyst, reaching a yield of 47.0% for Ru/Pd and quantitative yields for mono-Pd when [Al]/[Pd] = 2500 and [NBE]/[Pd] = 20,000 molar ratios were employed, both at 60 °C. [ABSTRACT FROM AUTHOR]

This paper adopts a morphological approach to the reduplication of the past-tense augment in Cypriot Greek and explores the morphotactic constraints that apply. Phonological reduplication phenomena have been addressed in morphology by developing a framework that can account for both doubling and metathesis. This phenomenon has been a focus of discussion, but less is known about the application of this mechanism to tense prefixes, known as augments. Doubling of the augment appears in verbal complexes depending on the position of its components, what I will argue are cases that support the post-syntactic morphological doubling and metathesis analysis in Distributed Morphology. The data from this non-standard variety provide a novel analysis of augments and contribute to a better understanding of their distribution by redefining this phenomenon as morphological and supporting a unified framework for the formalism designed to account for similar post-syntactic morphological phenomena. [ABSTRACT FROM AUTHOR]

This work presents an examination of the selective functionalization of norbornadiene through nitrile oxide 1,3-dipolar cycloaddition/ring-opening metathesis (ROM)/cross-metathesis (CM) protocols. Functionalization of commercially available norbornadiene provided novel bicyclic scaffolds with multiple stereogenic centers. The synthesis involved selective cycloadditions, with subsequent ROM of the formed cycloalkene-fused isoxazoline scaffolds and selective CM by chemodifferentiation of the olefin bonds of the resulting alkenylated derivatives. Various experimental conditions were applied for the CM transformations with the goal of exploring substrate and steric effects, catalyst influence and chemodifferentiation of the olefin bonds furnishing the corresponding functionalized, fluorine-containing isoxazoline derivatives.

Calcium and zinc carboxylates were prepared from palm fatty acid distillate, a byproduct of palm oil refining, via metathesis in aqueous ethanol. The formations of both metal carboxylates have been confirmed by infrared spectroscopy and x-ray diffraction analysis. Thermogravimetric analysis has shown that the prepared calcium and zinc carboxylates are practically stable while their weight losses are 14% at 393 °C and 19% at 311 °C, respectively. The efficacy of the metal carboxylates in their mixtures in stabilizing polyvinyl chloride against heat has also been studied by using static and dynamic tests. The calcium to zinc ratio of 4:1 has been found to give the longest stability time under the studied condition. The mixed calcium/zinc carboxylates demonstrate a synergism effect with pentaerythritol. The results reveal that mixed calcium/zinc carboxylates from palm fatty acid distillate are effective in stabilizing polyvinyl chloride against heat.

[Display omitted] • Olefin metathesis is a commercially successful method for converting less valuable olefins into more valuable ones; • Modification of the γ-Al 2 O 3 acidic properties by treatment with NH 4 HF 2 , (NH 4) 2 SiF 6 , H 3 BO 3 leads to a significant increase in the catalytic activity of MoO 3 /Al 2 O 3 systems in propylene metathesis; • An increase in conversion in the propylene metathesis reaction correlates with an increase in the concentration of strong Brønsted acid sites on the surface of the catalysts; • The formation of centers active in propylene metathesis occurs when the substrate interacts with strong Brønsted, but not Lewis acid sites on the surface of the catalyst; • Highly selective promoted olefin metathesis catalyst provides propylene conversion 8.5 times higher compared to classical, unmodified MoO 3 /Al 2 O 3 systems. One important way to increase the production of higher-margin products from less valuable unsaturated hydrocarbons is the widely used process of catalytic metathesis. Progress in the development of more advanced metathesis catalysts is hampered by obvious gaps in scientific knowledge about this process. This work is aimed at establishing the influence of physicochemical properties of Mo-containing lower olefins metathesis catalysts and developing methods for increasing their activity through promotion. A classic support for Mo-oxide metathesis catalyst was promoted with NH 4 HF 2 , (NH 4) 2 SiF 6 , H 3 BO 3 additives. The synthesized systems were analyzed by a large set of methods. The catalytic properties of obtained systems were determined in the propylene metathesis reaction. It was shown that the proposed promotion leads to an increase in activity of the catalyst up to 8.5 times. It was shown that strong Brønsted acid sites play a decisive role in increasing activity. In addition, it has been experimentally proven that the formation of active centers occurs when the substrate interacts with Brønsted, but not Lewis acid sites on the surface of the catalyst. The discoveries obtained in this work can serve as the basis for the creation of a new generation highly active lower olefins metathesis catalysts. [ABSTRACT FROM AUTHOR]

A number of alkali organometallic complexes with suitable thermodynamic properties and high capacity for hydrogen storage have been synthesized; however, few transition metal–organic complexes have been reported for hydrogen storage. Moreover, the synthetic processes of these transition metal–organic complexes via metathesis were not well characterized previously, leading to a lack of understanding of the metathesis reaction. In the present study, yttrium phenoxide and lanthanum phenoxide were synthesized via metathesis of sodium phenoxide with YCl3 and LaCl3, respectively. Quasi in situ NMR, UV-vis, and theoretical calculations were employed to characterize the synthetic processes and the final products. It is revealed that the electron densities of phenoxides in rare-earth phenoxides are lower than in sodium phenoxide due to the stronger Lewis acidity of Y3+ and La3+. The synthetic process may follow a pathway of stepwise formation of dichloride, monochloride, and chloride-free species. Significant decreases in K-band and R-band absorption were observed in UV-vis, which may be due to the weakened conjugation effect between O and the aromatic ring after rare-earth metal substitution. Two molecular structures, i.e., planar and nonplanar, are identified by theoretical calculations for each rare-earth phenoxide. Since these two structures have very close single-point energies, they may coexist in the materials.

Herein, we report the enantiospecific synthesis of two artificial glutamate analogs designed based on IKM-159, an antagonist selective to the AMPA-type ionotropic glutamate receptor. The synthesis features the chiral resolution of the carboxylic acid intermediate by the esterification with ʟ-menthol, followed by a configurational analysis by NMR, conformational calculation, and X-ray crystallography. A mice in vivo assay showed that (2R)-MC-27, with a six-membered oxacycle, is neuroactive, whereas the (2S)-counterpart is inactive. It was also found that TKM-38, with an eight-membered azacycle, is neuronally inactive, showing that the activity is controlled by the ring C.

A detailed investigation was conducted on the factors influencing the properties of silica-supported tungsten oxide catalysts for propene metathesis. A principal goal of this work was to identify the processes involved in the formation of catalytically active sites. To probe the influence of dispersion, samples were prepared across a range of W loadings using two methods of catalyst preparation: incipient wetness impregnation of amorphous silica and ion exchange of mesoporous SBA-15. The samples were characterized by nitrogen adsorption, UV-vis, Raman, and X-ray absorption spectroscopy (XAS). Catalytic activity was observed to increase with W surface concentration up to the point where WO3 nanoparticles formed. The catalytic performance of all samples was enhanced 2-fold by pretreatment in He, in comparison to pretreatment in air. In situ characterization of samples pretreated in He by Raman and XAS shows an increase in the relative concentration of isolated dioxo W(6+) species relative to mono-oxo W(6+) species, and in situ XAS data collected during propene metathesis indicated that a similar conversion occurs for air-pretreated samples in the presence of propene. For both air- and He-pretreated catalysts an activation period was observed, during which the activity increased and attained steady-state activity. This period was significantly longer for air-pretreated catalysts and was accompanied by the transient formation of acetone. While acetone was not observed during the much shorter transient of He-pretreated samples, in situ XAS provided evidence of reduction occurring in these samples upon contact with propene. It is also notable that, independent of the manner of catalyst preparation or pretreatment, the rate of propene metathesis is first order in propene and exhibits an activation energy of 200 kJ/mol. A model is proposed to explain why only a fraction of the isolated tungstate species is active for propene metathesis (∼5%) and why this fraction increases with increasing concentration of W dispersed on silica. (Chemical Equation Presented).

A series of neoflav-3-enes with a variety of natural substitution patterns was prepared from 1-(allyloxy)-2-[1-(aryl)vinyl]benzenes by Grubbs second generation (GII) catalyst-promoted ring-closing metathesis (67 - 99% yield). The 1-(allyloxy)-2-[1-(phenyl)vinyl]benzene substrates were accessible in yields of 52 - 94% from the corresponding 2-(allyloxy)acetophenones via a Grignard reaction and Lewis acid-promoted dehydration, either in a one pot process in the presence of Al(OTf)3 or in consecutive steps with CuSO4 as dehydrating agent. [ABSTRACT FROM AUTHOR]

Tebbe methylenation and ring-closing metathesis with Grubbs second generation catalyst were investigated as key steps in the synthesis of flav-2-enes with natural substitution patterns. The effect of aromatic substituents on the electron densities of the allyl and vinyl moieties and the effect thereof on methylenation and ringclosing metathesis, is discussed. [ABSTRACT FROM AUTHOR]

Copyright of Cuadernos de Lingüística de el Colegio de México is the property of El Colegio de Mexico AC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Linguistica Lithuanica is the property of Institute of the Lithuanian Language and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Scholars have discussed metathesis as a phonological process involving only the segmental phonemes. There have also been seminal papers on tone as a very important issue in phonology, but none has considered studying metathesis in relation to tone. This paper re-examines metathesis in Igbo with a view to establishing that the process involves both the segmental phonemes and the supra-segments (tone). Data obtained from Igbo texts and Ogbunike Igbo variety are descriptively and acoustically analysed. The results reveal that tone metathesis sometimes occurs in Igbo during connected speech, particularly across word boundary where the first word must have a High Downstep (H ↓H) tone sequence and the second word is High High (H H) tone sequence. Irrespective of the application of the correct tone sequences, tone metathesis can never occur if the first word is in its infinitive form. It is concluded that metathesis involves both the segmental phonemes and suprasegments (tone) in the Igbo language. [ABSTRACT FROM AUTHOR]

This paper studies the process of sound correspondences that occur in Modern Standard Arabic (MSA), Moroccan Arabic (MAR), and Najdi Arabic (NAR). It attempts to find answers for the following questions: a) What are the identical word pairs, words couples that have a phonemic correspondence, a phonetic similarity, and a pair of words that contains difference of one phoneme, b) What are the process of morphophonemic in the form of assimilation, metathesis, and epenthesis. It is addressed to portray the process of morphophonemic assimilation, metathesis and epenthesis in three Arabic languages using Crowley’s theory. This study used 207 of Morris Swadesh's basic vocabulary as the key standard procedure for collecting data. The criteria adopted to analyze the data were orthographic, sound-change, phonological, and morpheme contrast. This research used descriptive qualitative method. The source of the data was basic-word vocabulary. The data were gathered from three dictionaries as sources to get information. The data were analyzed by using structural linguistics, especially phonology, morphology, and semantics. This investigation informed several aspects of findings such as identifying prefixes, suffixes, assimilation, metathesis, and epenthesis. Using the Swadesh vocabulary list, the results of this study found 207 vocabularies for each language. By analyzing parts of speech, it was found that these vocabularies can be classified into five-word classes, namely, nouns, pronouns, verb, adjectives, adverbs, and determiners.

The discovery and preparation of important molecules rely on the synthetic chemist's ability to valorize common feedstock materials, such as petroleum or biomass. Key to this endeavor is the design of efficient methods to introduce, remove or interconvert functional groups. Our group has a longstanding interest in developing conceptually novel catalytic reactions for the installation of unprotected amines, the selective activation of C–O bonds (in polyols) and the transfer (shuttle) or exchange (metathesis) of functionalities between two molecules. This account describes representative examples from our group in these different research areas.

Taqi F Hashmi Family Physician, Primary Health Care Corporation, Doha, QatarCorrespondence: Taqi F HashmiFamily Physician, Primary Health Care Corporation, PO Box 26555, Doha, QatarEmail thashmi@phcc.gov.qaAbstract: A commentary and analysis on the miscommunication of medication names between native Arabic-speaking patients and pharmacists with a native English-speaking family physician using Medical English as a Lingua Franca (MELF), in a healthcare context. An important cause of communication difficulties is the different way native English and native Arabic speakers linguistically process medication names when using MELF. This is likely to be explained by the differences in the native grammars of English and Arabic which determine differences in pronunciation and predict potential error prone groupings of letters and sounds. This in turn leads to repeating linguistic errors such as epenthesis (insertion of additional vowels between consonants) and metathesis (the swapping of adjacent consonants). The article highlights a case where both epenthesis and metathesis occur simultaneously leading to a potential serious adverse event through a medication error and suggests further avenues of research to minimise such errors.Keywords: medication errors, Arabic, metathesis, epenthesis, Medical English as a Lingua Franca, MELF

The olefin metathesis reaction has found numerous applications in organic synthesis. This is due to a number of advantages, such as the tolerance of most functional groups and sterically demanding olefins. This article reviews recent advances in the application of the metathesis reaction, particularly the metathetic cyclization of dienes and enynes, in synthesis protocols leading to (hetero)aromatic compounds.

Theoretical assessment of the protonation reaction in the activation of propene on hydroxylated Mo(VI) and W(VI) metathesis catalysts is presented in this paper using the density functional theory calculations and five support clusters varying from simple SiO4H3 clusters to a large Si4O13H9 cluster. The bond distances and thermochemical data were similar for most of the clusters. The formation of isopropoxide was more favorable than a propoxide counterpart bonded via the primary carbon atom, with the Gibbs free energies of –3.73 and –7.78 kcal/mol, respectively, for the W catalyst. Overall, the 1T cluster models with optimized H atoms or an all-relaxed alternative would be considered appropriate replacements for a larger 4T cluster model saturated with OH groups and optimized terminal hydrogen atoms. The largest deviations in the energetic data were observed between the protonated structures formed on the two larger clusters saturated with either OH or H groups.

This study sheds light on the relationship between the Sonority Sequencing Principle (SSP) and syllable structure in Sabzevari, a Persian vernacular spoken in the Sabzevar area of Northeast Iran. Optimality Theory (OT), as a constraint-based approach, is utilized to scrutinize sonority violation and its repair strategies. The results suggest that obedience to the SSP is mandatory in Sabzevari, as shown through the treatment of word-final clusters in Standard Persian words which violate the SSP. These consonant clusters are avoided in Sabzevari by two phonological processes: vowel epenthesis and metathesis. Vowel epenthesis is motivated by final consonant clusters of the forms /fricative+coronal nasal/, /plosive+bilabial nasal/, /fricative+bilabial nasal/, /plosive+rhotic/, /fricative+rhotic/, and /plosive+lateral/. Metathesis, as another repair strategy for sonority sequencing violations, occurs when dealing with final consonant clusters of the forms /plosive+fricative/and / fricative+lateral/.

In this study, two types of Rare Earth (RE) 3-furoate complexes were synthesized by metathesis reactions between RE chlorides or nitrates and preformed sodium 3-furoate. Two different structural motifs were identified as Type 1RE and Type 2RE. The Type 1RE monometallic complexes form 2D polymeric networks with the composition [RE(3fur)3(H2O)2]n (1RE = 1La, 1Ce, 1Pr, 1Nd, 1Gd, 1Dy, 1Ho, 1Y; 3furH = 3-furoic acid) while Type 2RE bimetallic complexes form 3D polymeric systems [NaRE(3fur)4]n (2RE = 2Ho, 2Y, 2Er, 2Yb, 2Lu). The stoichiometric mole ratio used (RE: Na(3fur) = 1:3 or 1:4) in the metathesis reaction determines whether 1RE or 2RE (RE = Ho or Y) is formed, but 2RE (RE = Er, Yb, Lu) were obtained regardless of the ratio. The corrosion inhibition behaviour of the compounds has been examined using immersion studies and electrochemical measurements on AS1020 mild steel surfaces by a 0.01 M NaCl medium. Immersion test results revealed that [Y(3fur)3(H2O)2]n has the highest corrosion inhibition capability with 90% resistance after 168 h of immersion. Potentiodynamic polarisation (PP) measurements also indicate the dominant behaviour of the 1Y compound, and the PP curves show that these rare earth carboxylate compounds act predominantly as anodic inhibitors.

Zinc metal soaps are of great importance in the manufacture of personal care products and other industrial applications. Variations in the soaps and their properties are usually due to the type of oil used in the synthesis. Shea butter (Vitellaria paradoxa), being a valuable industrial raw material, was investigated for the synthesis of zinc metal soap. Locally obtained shea butter was characterized, refined and used to synthesize metal soap of zinc which was characterized. The zinc soap produced exhibited an off-white appearance, pH of 7.8, non-foaming, and no free alkalinity present. The functional groups in the soap were confirmed by FTIR.