Waste not, want not: CO2 (re)cycling into block polymers

A new way to combine two different polymerisation reactions, using a single catalyst, results in efficient block polymer synthesis. The selective polymerisation of mixtures of L-lactide-O-carboxyanhydride and cyclohexene oxide, using a di-zinc catalyst in a one-pot procedure, allows the preparation of poly(L-lactide-b-cyclohexene carbonate). The catalysis near quantitatively recycles the carbon dioxide released during polyester formation into the subsequent polycarbonate block, with an atom economy of up to of 91%

Positive Reappraisals After an Offense: Event-related Potentials and Emotional Effects of Benefit-finding and Compassion

Using a within subjects design, three emotion regulation strategies (compassion‐focused reappraisal, benefit‐focused reappraisal, and offense rumination) were tested for their effects on forgiveness, well‐being, and event‐related potentials (ERPs). Participants (N = 37) recalled a recent interpersonal offense as the context for each emotion regulation strategy. Both decisional and emotional forgiveness increased significantly for the two reappraisal strategies compared to offense rumination. Compassion‐focused reappraisal prompted the greatest increase in both decisional and emotional forgiveness. Furthermore, both reappraisal strategies increased positively oriented well‐being measures (e.g., joy, gratitude) compared to offense rumination, with compassion‐focused reappraisal demonstrating the largest effect on empathy. Late positive potential (LPP) amplitudes in response to unpleasant affect words were larger following the benefit‐focused reappraisal strategy, indicating frontal LPP augmentation due to affective incongruence of the unpleasant stimuli with the positive, silver‐lining orientation of the benefit‐focused reappraisal emotion regulation strategy

Simple phosphinate ligands access zinc clusters identified in the synthesis of zinc oxide nanoparticles

The bottom-up synthesis of ligand-stabilized functional nanoparticles from molecular precursors is widely applied but is difficult to study mechanistically. Here we use 31P NMR spectroscopy to follow the trajectory of phosphinate ligands during the synthesis of a range of ligated zinc oxo clusters, containing 4, 6 and 11 zinc atoms. Using an organometallic route, the clusters interconvert rapidly and self-assemble in solution based on thermodynamic equilibria rather than nucleation kinetics. These clusters are also identified in situ during the synthesis of phosphinate-capped zinc oxide nanoparticles. Unexpectedly, the ligand is sequestered to a stable Zn11 cluster during the majority of the synthesis and only becomes coordinated to the nanoparticle surface, in the final step. In addition to a versatile and accessible route to (optionally doped) zinc clusters, the findings provide an understanding of the role of well-defined molecular precursors during the synthesis of small (2–4 nm) nanoparticles

Polynuclear alkoxy–zinc complexes of bowl-shaped macrocycles and their use in the copolymerisation of cyclohexene oxide and CO2

The reactions between alcohols and the tetranuclear ethyl-Zn complexes of an ortho-phenylene-bridged polypyrrole macrocycle, Zn4Et4(L1) 1 and the related anthracenyl-bridged macrocyclic complex, Zn4Et4(THF)4(L2) 2 have been studied. With long-chain alcohols such as n-hexanol, the clean formation of the tetranuclear hexoxide complex Zn4(OC6H13)4(L1) 3 occurs. In contrast, the use of shorter-chain alcohols such as i-propanol results in the trinuclear complex Zn3(μ2-OiPr)2(μ3-OiPr)(HL1) 4 that arises from demetalation; this complex was characterised by X-ray crystallography. The clean formation of these polynuclear zinc clusters allowed a study of their use as catalysts in the ring-opening copolymerisation (ROCOP) reaction between cyclohexene oxide and CO2. In situ reactions involving the pre-catalyst 1 and n-hexanol formed the desired polymer with the best selectivity for polycarbonate (90%) at 30 atm CO2, whilst the activity and performance of pre-catalyst 2 was poor in comparison

Ultrarapid cerium(III)–NHC catalysts for high molar mass cyclic polylactide

The EPSRC are acknowledged for research funding through the Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT, EP/ L016419/1, R. W. F. K., P. M. D. A. E.), EP/J018139/1, the UK Catalysis Hub (EP/K014714/1, P. L. A., C. K. W., S. K. R.), EP/M010554/1 (P. L. A.) and EP/S018603/1 (C. K. W.). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 740311, P.L.A.).Cyclic polyesters could improve the properties of degradable plastics, but routes to them that provide a product with faster rates, higher molar mass, and greater selectivity for cyclic vs linear polymer are needed. Here, homogeneous Ce(III)–N-heterocyclic carbene (NHC) catalysts show outstanding activities (turn-over-frequency (TOF) > 864 000 h–1), excellent control, and selectivity for cyclic polylactide (PLA) topology (>95%), yielding high molar mass PLA (60 < Mn < 250 kg mol–1). They efficiently produce cyclic PLA from rac-lactide or l-lactide and aliphatic cyclic polyesters from ε-caprolactone or β-butyrolactone. The enhanced performances are only achievable from combining cooperative Lewis acidic cerium(III) and hemilabile N-heterocyclic carbene functionalities.PostprintPostprintPeer reviewe

Perceptions, Barriers, and Suggestions for Creation of a Tobacco and Health Website among American Indian/Alaska Native College Students

Information concerning American Indian/Alaska Native (AI/AN) Internet use and health information needs is dearth. Our research team explored Internet use among AI/AN college students to determine Internet use in relation to health information seeking behaviors. We used a tobacco site example for participants to describe what they desired in a health site designed specifically for AI/AN. Using a community-based participatory research approach, we conducted 14 focus groups with AI/AN college students (N=108), to better understand their perceptions of and attitudes toward Internet use and health information needs. Daily Internet use was reported across strata yet health topics investigated differed among groups. Participants in all strata desired a health website that was easy to navigate and interactive. Respectful representation of Native culture was a concern, yet no consensus was reached for a multi-tribal audience. Participants felt a website should use caution with cultural depictions due to the possible misinterpretation. Overall, participants agreed that recreational and traditional tobacco use should be differentiated and the variation of traditional use among tribes acknowledged. Data concerning Internet use for health information among AI/AN college students are needed to establish baseline indicators to effectively address disparities

Engaging the agricultural community in the development of mental health interventions: a qualitative research study

Background: Farmers and those involved in the wider agricultural industry have a high suicide rate. They are also a ‘hard to reach’ group who make less than average use of mental health services. There is therefore a need to understand how best to develop interventions that meet their needs. The aims of this study were to develop a deeper understanding of the farming context and target population and to engage farmers in the shaping of two potential mental health interventions that could be incorporated in a pilot RCT. Methods: The study was informed throughout by a reference group, who assisted in co-production of the research materials. A snowball approach was used to recruit interested individuals who had an association with farming. Twenty one telephone interviews were undertaken and analysed using the six phases of thematic analysis proposed by Braun and Clarke. Results: Key themes (and sub-themes shown in brackets) related to the study aims were: everyday life (work-life balance; isolation and loneliness); farm management (technology and social media; production, people management, learning and teaching; external pressures; livestock and farm production; financial aspects); demographics (effects of aging); engagement (appropriate wording when talking about mental health; recognising need for help; religion; normalising mental health issues; approaching the conversation); training (mental health training for supporters of the farming community; health &amp; safety and the inclusion of mental health training); and personal stories and experiences, which was an emerging theme. Conclusions: Recruiting farmers into research studies is best done by meeting farmers where they are found, for example, farmers marts. Accessibility of content, tailoring to the farming community, and guided support are key to effective recruitment and retention

Catalytic Synergy Using Al(III) and Group 1 Metals to Accelerate Epoxide and Anhydride Ring-Opening Copolymerizations

The controlled synthesis of polyesters via epoxide/anhydride ring-opening copolymerization is a versatile and generally applicable method to make many sustainable polymers, but catalyst activities are limited and the required catalyst loadings are typically high. Here, novel heterodinuclear complexes, featuring Al(III)/M(I) (M = Na, K, Rb, Cs), show exceptional activities for phthalic anhydride and cyclohexene oxide copolymerization (catalyst = Al(III)/K(I), turnover frequency = 1072 h–1, 0.25 mol % catalyst loading vs anhydride, 100 °C). The Al(III)/K(I) catalyst is also tolerant to low loadings, maintaining a good performance at 0.025 mol % catalyst vs anhydride loading and 0.005 mol % vs epoxide. It rapidly polymerizes other epoxide/anhydride combinations yielding various semi-aromatic, rigid, and/or functionalizable polyesters and also shows activity in carbon dioxide/epoxide copolymerizations. The results of structure–activity, X-ray crystallography, polymerization kinetics, and density functional theory investigations support a mechanism with chain growth alternation between the metals. The rate-limiting step is proposed to involve epoxide coordination at Al(III) with K(I) carboxylate attack. Future exploitation of abundant and inexpensive Group 1 metals to deliver synergic polymerization catalysts is recommended