259 research outputs found
Organoaluminium complexes derived from anilines or Schiff bases for the ring-opening polymerization of Δ-Caprolactone, Ύ-Valerolactone and rac-Lactide
Reaction of R1R2CHN=CH(3,5-tBu2C6H2-OH-2) (R1 = R2 = Me L1H; R1 = Me, R2 = Ph L2H; R1 = R2 = Ph L3H) with slightly greater than one equivalent of R33Al (R3 = Me, Et) afforded the complexes [(L1â3)AlR32] (L1, R3 = Me 1, R3 = Et 2; L2, R3 = Me 3, R3 = Et 4; L3 R3 = Me 5, R3 = Et 6); complex 1 has been previously reported. Use of the N,O-ligand derived from 2,2âČ-diphenylglycine afforded either 5 or the byproduct [Ph2NCH2(3,5-tBu2C6H2-O-2)AlMe2] (7). The known Schiff base complex [2-Ph2PC6H4CH2(3,5-tBu2C6H2-O-2)AlMe2] (8) and the product of the reaction of 2-diphenylphosphinoaniline 1-NH2,2-PPh2C6H4 with Me3Al, namely {Ph2PC6H4N[(Me2Al)2”-Me](”-Me2Al)} (9), were also isolated. For structural and catalytic comparisons, complexes resulting from the interaction of Me3Al with diphenylamine (or benzhydrylamine), namely {Ph2N[(Me2Al)2”-Me]} (10) and [Ph2CHNH(”-Me2Al)]2·MeCN (11), were prepared. The molecular structures of the Schiff proligands derived from Ph2CHNH2 and 2,2âČ-Ph2C(CO2H)(NH2), together with those of complexes 5, 7 and 9â11·MeCN were determined; 5 contains a chelating imino/phenoxide ligand, whereas 7 contains the imino function outside of the metallocyclic ring. Complex 9 contains three nitrogen-bound Al centres, two of which are linked by a methyl bridge, whilst the third bridges the N and P centres. In 10, the structure resembles 9 with a bridging methyl group, whereas the introduction of the extra carbon in 11 results in the formation of a dimer. All complexes have been screened for their ability to promote the ring-opening polymerization (ROP) Δ-caprolactone, ÎŽ-valerolactone or rac-lactide, in the presence of benzyl alcohol, with or without solvent present. Reasonable conversions were achievable at room temperature for Δ-caprolactone when using complexes 7, 9 and 12, whilst at higher temperatures (80â110 °C), all complexes produced good (> 65â%) to quantitative conversions over periods as short as 3 min, albeit with poor control. In the absence of solvent, conversions were nearly quantitative at 80 °C in 5 min with better agreement between observed and calculated molecular weight (Mn). For rac-lactide, conversions were typically in the range 71â86â% at 110 °C in 12 h, with poor control affording atactic polylactide (PLA), whilst for ÎŽ-valerolactone more forcing conditions (12â24 h at 110 °C) were required for high conversion. Co-polymerization of Δ-caprolactone with rac-lactide afforded co-polymers with appreciable lactide content (35â62.5â%); the reverse addition was ineffective, affording only (polycaprolactone) PCL
Mono- and tetra-nuclear copper complexes bearing bis(imino)phenoxide derived ligands: catalytic evaluation for benzene oxidation and ROP of epsilon-caprolactone
Complexes of the type [Cu(L)2] (1) and [Cu4L2(ÎŒ4âO)(OAc)4] (2) have been obtained from the reaction of the phenoxydiimine 1,3-(2,6-R22C6H3N=CH)2-5-R1C6H2OH-2 (LH) (where R1 = Me, tBu, Cl; R2 = Me, iPr) with copper(II) acetate [Cu(OAc)2]; changing the molar ratio of the reactants affords 10 differing amounts of 1 or 2. Reaction of the parent dialdehyde [1,3-(CHO)2-5-MeC6H2OH-2] with [Cu(OAc)2] in the presence of Et3N afforded, following work-up, a polymeric chain (3) comprising {[Cu2(OAc)4]OAc}n, HNEt3 and MeCN. The crystal structures of 1 (R1 = Me, R2 = iPr 1a; R1 = Cl, R2 = iPr 1b), 2 (R1 = Me, R2 = Me 2a; R1 = Me, R2 = iPr 2b; R1 = tBu, R2 = Me 2c; R1 = Cl, R2 = Me 2d; R1 = Cl, R2 = iPr 2e; R1 = tBu, R2 =iPr 2f) and 3 are reported (synchrotron radiation was necessary for 3). The 15 magnetic properties of the cluster 2b are presented. Complexes of type 2 and 3 were screened for the ring opening polymerization (ROP) of Δ-caprolactone, with or without benzyl alcohol present, under a variety of conditions, however only trace polymer was isolated. The electrochemistry of all complexes was also investigated, together with their ability to catalyze benzene oxidation (using hydrogen peroxide); although low conversions were observed, the tetra-nuclear complexes exhibited excellent selectivity
Texts of Kolima dialect of Yukaghir
<p>Clinical chemistry data of monkeys fed on diets containing GM rice or non-GM rice.</p
Parental Influences on Adolescent Friendship Pairings
Despite the fact that the processes of homophily, propinquity, and parenting have been identified as prominent precursors to friendship formation, little research has examined how they jointly affect youthsâ friendships. The current study used Add Health data to fit into random crossed effect models and extended prior literature by connecting homophily and propinquity studies to parent-peer linkage research to quantify whether and how similarity of parentsâ characteristics (SES, income, and educational aspirations) and practices (caring, monitoring, availability, and involvement) contribute to the relationship between homophily (youthsâ similar academic performance [using AHAA], educational aspirations, delinquency, and drug use) and/or propinquity (neighborhood and local position propinquity) and friendship formation.
The result indicates two pathways: fundamental influences and moderation influences through which parents influence the likelihood of friendship pairing. Findings suggested that parental influences worked more through homophily than through propinquity to fundamentally affect friendship pairings for both female and male. In terms of moderation, parental influences moderated propinquity more than homophily to affect friendship pairings. The research also identified gender differences. Three parental measures: SES, Educational Aspiration for Youths, and Smoking and Drinking had fundamental and moderation influences on same race female friendship pairings. Three parental measures: SES, Educational Aspiration for Youths, and Monitoring had fundamental and moderation influences on same race and age male friendship pairing
When to Appeal to Cultural Capital in Advertisements? Cultural Capital Appeals Increase Purchase Intentions for High- But Not Low-priced Products
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Additional file 3: of Cochrane systematic reviews and co-publication: dissemination of evidence on interventions for ophthalmic conditions
Reasons six co-publications had a different number of included studies compared to the CEVG review
Smartphone use increases the likelihood of making short-sighted financial decisions
Contextualizing in the digitalization of personal finance (e.g., mobile banking), the present research explores how financial decisions made on smartphones (vs. laptops or tablets) are more likely to be shortsighted, manifesting in being unwilling to save for retirement, referring to recent information while making financial decisions, and opting for instant but smaller rewards. We trace the effect to smartphonesâ affordance of ubiquity, an attribute that allows users to satisfy various needs with considerable flexibility of time and space and prompts users to seek instant gratifications. We also rule out potential alternative factors that might account for this effect, including haptic gratification, direct-touch effect, task difficulty, thinking style, concentration, and the hedonic usage of the devices by users. Furthermore, we demonstrate that prompting users to deliberate on their decisions successfully attenuates the effect. Implications for the development of interventions are discussed
Hybridized ElectromagneticâTriboelectric Nanogenerator for Scavenging Air-Flow Energy to Sustainably Power Temperature Sensors
We report a hybridized nanogenerator with dimensions of 6.7 cm Ă 4.5 cm Ă 2 cm and a weight of 42.3 g that consists of two triboelectric nanogenerators (TENGs) and two electromagnetic generators (EMGs) for scavenging air-flow energy. Under an air-flow speed of about 18 m/s, the hybridized nanogenerator can deliver largest output powers of 3.5 mW for one TENG (in correspondence of power per unit mass/volume: 8.8 mW/g and 14.6 kW/m<sup>3</sup>) at a loading resistance of 3 MΩ and 1.8 mW for one EMG (in correspondence of power per unit mass/volume: 0.3 mW/g and 0.4 kW/m<sup>3</sup>) at a loading resistance of 2 kΩ, respectively. The hybridized nanogenerator can be utilized to charge a capacitor of 3300 ÎŒF to sustainably power four temperature sensors for realizing self-powered temperature sensor networks. Moreover, a wireless temperature sensor driven by a hybridized nanogenerator charged Li-ion battery can work well to send the temperature data to a receiver/computer at a distance of 1.5 m. This work takes a significant step toward air-flow energy harvesting and its potential applications in self-powered wireless sensor networks
Hybridized ElectromagneticâTriboelectric Nanogenerator for Scavenging Biomechanical Energy for Sustainably Powering Wearable Electronics
We report a hybridized electromagneticâtriboelectric nanogenerator for highly efficient scavenging of biomechanical energy to sustainably power wearable electronics by human walking. Based on the effective conjunction of triboelectrification and electromagnetic induction, the hybridized nanogenerator, with dimensions of 5 cm Ă 5 cm Ă 2.5 cm and a light weight of 60 g, integrates a triboelectric nanogenerator (TENG) that can deliver a peak output power of 4.9 mW under a loading resistance of 6 MΩ and an electromagnetic generator (EMG) that can deliver a peak output power of 3.5 mW under a loading resistance of 2 kΩ. The hybridized nanogenerator exhibits a good stability for the output performance and a much better charging performance than that of an individual energy-harvesting unit (TENG or EMG). Furthermore, the hybridized nanogenerator integrated in a commercial shoe has been utilized to harvest biomechanical energy induced by human walking to directly light up tens of light-emitting diodes in the shoe and sustainably power a smart pedometer for reading the data of a walking step, distance, and energy consumption. A wireless pedometer driven by the hybrid nanogenerator can work well to send the walking data to an iPhone under the distance of 25 m. This work pushes forward a significant step toward energy harvesting from human walking and its potential applications in sustainably powering wearable electronics
sj-docx-1-pac-10.1177_18344909221147782 - Supplemental material for Smartphone use increases the likelihood of making short-sighted financial decisions
Supplemental material, sj-docx-1-pac-10.1177_18344909221147782 for Smartphone use increases the likelihood of making short-sighted financial decisions by Tianran Wang, Wei-Fen Chen, Xue Wang and Xiucheng Fan in Journal of Pacific Rim Psychology</p
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