The novel 2,6-trimethylsilyl-3,5-(2'-pyridyl)phosphinine has been synthesized and its coordination chemistry with Cu(I) and Au(I) was investigated. Selective binding through either the phosphorus atom or the pendant pyridyl groups was achieved, yielding monomeric, dimeric, and polymeric complexes. The use of copper halides produced rather structurally diverse coordination compounds, with architectures dependent on the type of halide, copper loading, and solvent, whereas Au(I) exclusively formed monomeric species. Quaternization of the ligand with alkylating agents suppressed N-coordination, enabling further study of the resulting cationic derivative with the same metals. These results highlight strongly tuneable coordination behaviour of this new phosphinine scaffold.

The stabilization of positive and negative charges by alkyl groups (in particular) in organic compounds is often described as polarizability, but it can also be described as hyperconjugation (and related stereoelectronic effects). To a large extent, how one describes charge stabilization depends on the bonding model used. One can only talk about hyperconjugation in the context of a localized bonding model (hybridization). However, using this bonding model, it is less intuitive to talk about polarization of the whole molecule, which requires full molecular orbitals. It is important in chemical education to be aware of the limitations and intersections of the models we are using. In this work, we show that the polarization of alkyl chains in representative molecules, either by a computationally applied field or by a charge in the molecule, is reflected in changes in hyperconjugative interactions throughout the structure in a logical and predictable manner. This makes a clear and accessible point that hyperconjugation and polarizability are simply two models (at least for charge stabilization) that explain the same phenomenon. In this work, we identify advantages and limitations of each explanation, giving educators examples that can be used in teaching at various levels.

Nine {ONO} ligands were prepared and treated with ZnEt2 to form a range of complexes. The resulting complexes were characterised in solution through H-1 and C-13{H-1} NMR spectroscopy, and in the solid state through single-crystal XRD and elemental analysis. Moderate reactivity towards lactide polymerisation was demonstrated, with hydroxyl complexes reaching high conversion in 1-2 minutes at 300: 1: 1. All complexes successfully degraded PLA to methyl lactate and the effect of reaction time, temperature and catalyst loading was explored. Zn(4)(2) successfully produced ethyl and n-butyl lactate and was shown to work in ambient conditions, albeit with reduced yield and selectivity. The production of BHET from waste PET was demonstrated with a selection of the most active catalysts. Zn(4)(2) was shown to be capable of sequential PLA/PET degradation and to be tolerant of HDPE/PVC contaminants.

Flushed wet wipes pose a significant pollution risk to river systems at both macro and micro levels. However, the link between their emissions and environmental contamination remains unclear. Here we integrated emissions-based modelling with existing data on wet wipe disposal and microfibre generation to predict the quantity of emissions entering river systems and the transport pathways involved. Results indicate that wastewater pathways, including sewer overflows, wastewater treatment plants, and agricultural runoff, are major conduits for these pollutants. Despite advanced wastewater treatment, substantial microfibre emissions still enter the environment. Extrapolating to larger scales reveals wet wipe pollution as an international issue requiring urgent attention. This research offers a comprehensive modelling framework applicable to various wastewater pollutants, providing valuable insights for policymakers and the water industry. Improved data on wet wipe disposal, fate, and spatially distributed wastewater systems are necessary to pinpoint their environmental risks more accurately.

This paper discusses hyperconjugative stereoelectronic effects in borazines. A series of alkyl-substituted borazines were synthesized and analysed by NMR spectroscopy and X-ray diffraction. Supported by NBO analyses, the significant decreases in 1JCH coupling constant for the CH groups adjacent to the boron atoms are consistent with the presence of and interactions. These interactions lower the electrophilicity of boron atoms, enhancing moisture stability and establishing these molecules as valuable scaffolds in synthetic chemistry and materials science.

It is commonly stated that alkyl groups exert an inductive electron-releasing effect when compared to hydrogen. This information has been given in numerous organic chemistry textbooks over the last 75 years. The evidence for this position is weak, and does not withstand scrutiny, and there is some evidence for the contrary position. We provide a significant body of computational data that clearly show that alkyl groups exert an inductive electron-withdrawing (-I) effect when compared to hydrogen. This revised position is not in conflict with experimental data, since alkyl group inductive effects are small and are likely to be masked by hyperconjugation/polarizability effects (particularly in charged species), and also by solvent effects.

We find there to be no significant difference between the inductive effects of four representative alkyl groups as determined by Hirshfeld charge analysis. The use of alkyl group electronegativity values shows no meaningful correlation with the electron-withdrawing/donating ability of the alkyl groups. The 13C NMR chemical shift diverges significantly from the calculated Hirshfeld charges, and we consider the latter to be a more reliable indicator of charge distribution.

Borazine and its derivatives can be considered critical doping units for engineering hybrid C(sp2)-based molecules with tailored optoelectronic properties. Herein, we report the first synthesis of hexa-arylborazines that, bearing ortho-substituted aryl moieties, extend three-dimensionally. Using a one-pot protocol, we first form an electrophilic chloroborazole and then react it with an aryl lithium (ArLi). By selecting the appropriate ortho-substituent, we can guide the ArLi to add to the BN-core in a specific way, ultimately controlling the stereochemical outcome of the three-substitution reaction. Rationalization of the stereochemical model through computational analysis allowed us to show that when aryl lithium nucleophiles bearing rigid long-range ortho-substituents are used, i.e., stiff substituents. The ortho-substituent shields its side of the electrophilic B3N3 core, biasing the incoming ArLi to add anti at each addition step, forming the final tri-aryl borazine exclusively as cc-isomer. Leveraging this stereoselective approach, prototypical multichromophoric borazine derivatives were prepared, and we showcased how the stereochemical arrangement of these chromophores distinctly influences their redox behavior. This methodology paves the way for previously inaccessible borazines to serve as privileged precursors to transcend the conventional bidimensionality associated with graphenoid systems and pioneer the construction of new forms of three-dimensional C(sp2)-based architectures.

The environmental degradation and fate of cellulose-based 'biodegradable' wet wipes under real-world conditions remain underexplored, particularly in urban freshwater systems where they are frequently discharged via toilet flushing. Building on previous mesocosm-based experiment, this study quantified in-situ degradation of two commercially available cellulose-based wipes labelled 'biodegradable' across ten urban rivers and streams and identified key environmental drivers of degradation. Tensile strength loss was used as a proxy measurement for wipe degradation alongside cotton strip bioassays as ecological benchmarks. Wipes rich in natural cellulose degraded substantially faster (Brand A: 6.69 ± 3.19 % per day) than those dominated by regenerated cellulose (Brand B: 3.12 ± 1.93 % per day) or cotton bioassay controls (2.22 ± 1.00 % per day). Degradation rates were shaped by microbial biomass, total dissolved solids, temperature, and river-level fluctuations, although exposure duration had the largest effect - suggesting complex interactions between physical and biological processes. Despite early-stage degradation, most wipes persisted after five weeks, challenging their biodegradability claims. These findings highlight potential ecological risks from persistent textile fibre pollution, emphasising the need for updated labelling and biodegradability standards that appropriately reflect real-world freshwater conditions, as well as greater scrutiny of plastic-free alternative products and their environmental fates in general.

Polyvinylpyrrolidone (PVP) is a synthetic water-soluble polymer (WSP) that does not readily biodegrade and has been detected in rivers in the mg L-1 range. Whilst previous studies have highlighted sublethal impacts of this chemical on freshwater species, cause of this toxicity remains unclear. The current study investigates how polymer molecular weight impacts the freshwater model species, Daphnia magna. Following OECD 211 guidelines, D. magna were exposed to PVP at levels reflecting those detected in European rivers, where the effect of two different molecular weights of the polymer were compared, both representing sizes commonly used in domestic products (PVP 40 kDa and 360 kDa). Two experiments were performed which differed in algal ration; Experiment 1 followed OECD 211 recommended rationing and Experiment 2 used concentrated algal rations, both assessing D. magna growth, survival and reproduction. No effects of PVP on D. magna were seen when algae rations were high, contrary to the inhibited growth observed for D. magna exposed to PVP 360 kDa, and the lethal effects of PVP 40 kDa when using the OECD recommended ration. Gel-permeation chromatography (GPC) analysis of PVP tank water samples suggests a polymeric structural change occurs only in the presence of D. magna, implying that ingestion of PVP by D. magna causes polymer-algae binding. This polymeric change was not observed when D. magna were absent in an equivalent polymer-algae solution. The findings highlight the need for more research investigating the underlying toxic effects of these polymers to inform chemical legislation as well as the need to accommodate molecular weight in environmental risk assessments.

The recognition of Cu 2+ and Hg 2+ ions along with the division of HeLa cells have been made using a fluorescein hydrazone. Its Cu 2+ complexes in turn recognize CN − and HSO 4 − ions.

The environmental fate of cellulose-based "biodegradable" wet wipes in freshwater ecosystems remains poorly understood, despite growing market demand and legislative shifts banning plastic-containing alternatives. This study evaluated the degradation behaviour of two commercially available biodegradable wet wipe brands in upland stream mesocosms mimicking real-world river conditions. Using tensile strength loss (TSL) as the primary degradation metric, wipe degradation was compared across varied pH, temperature, nutrient, and light regimes, alongside cotton strip controls. Results revealed that although degradation rates varied by material and environmental context, both wet wipe brands persisted in river systems for 5 weeks, with Brand A degrading ∼50 % faster than Brand B and nearly twice as fast as cotton controls. Degradation was significantly influenced by pH, temperature, and total dissolved solids, but not by wipe positioning in the water column (hyporheic, submerged, surface) or microbial biomass alone. Temperature-adjusted TSL (% per degree day) emerged as the most robust degradation metric, suggesting initial physical disintegration preceded microbial breakdown. These findings challenge current biodegradability claims and highlight the need for regulatory testing under environmentally relevant freshwater conditions to ensure truly biodegradable wet wipe products.

Water-soluble polymers (WSPs) are additives used as thickeners, stabilisers and flocculants in industry and in household products, including personal care products. Given their widespread use, it is likely WSPs enter the environment, particularly through wastewaters. This is of concern as there is little ecotoxicological research on their fate and behaviour once in the environment, which means their risk to aquatic life is not understood. The lack of suitable analytical techniques to detect, characterise and quantify WSPs hinders research on the potential impact of these polymers. A novel method has been developed that identifies polymers within a sample and separates them using gel-permeation chromatography (GPC). This is coupled with matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS), to quantify the polymer fractions using molecular weight information. This process has been carried out on a range of aqueous media. Polyethylene glycol (PEG) ingredients were successfully separated from non-polymeric material in a commercial shaving gel personal care product (PCP), before being quantified at 1.62 wt%. This method was applied to a spiked wastewater influent sample to demonstrate the extraction and separation of PEG from organic constituents such as dissolved organic matter (DOM). This highlighted the additional challenges of analysing WSPs in the environment, as factors such as sorption and biodegradation affected the total recovery of PEG, with an extraction efficiency of 53%. Overall, this method was applied for the extraction of PEG from a PCP with accurate quantification, before a proof-of-concept extraction from wastewater demonstrated the difficulties associated with WSP analysis in environmental samples. This method provides opportunities to use tandem GPC/MALDI-TOF MS to quantify WSPs in a broad array of environmental samples. Additional studies could include its application to wastewater or freshwater monitoring.

The water-soluble polymer polyvinylpyrrolidone (PVP) is an established ingredient in pharmaceutical and personal care product (PPCP) formulations. Due to its high usage and lack of biodegradability, it has been detected up to 7.0 mg L -1 in wastewater and 0.1 mg L -1 in the receiving freshwaters, with several studies showing detrimental sublethal effects in a range of aquatic species. A lack of simple analytical methods to detect and quantify PVP currently impacts further investigation into the cause of these sublethal effects. In this paper we propose a refractive index gelpermeation chromatography (GPC) method to quantify PVP, which includes the processing of raw chromatograms using line deconvolution to calculate peak area. The method was then applied to Daphnia magna exposed to PVP for 48 h. A limit of detection (LOD) and limit of quantification (LOQ) of 0.05 and 0.2 mg mL -1 respectively was determined, with a recovery of 78 % from spiked Daphnia magna . PVP was detected in the samples above the LOD but below the LOQ. This suggests PVP is ingested by Daphnia magna , which warrants further investigation into whether bioaccumulation of PVP could be causing the sublethal effects seen in other studies.

Borazine and its derivatives can be considered critical doping units for engineering hybrid C(sp2)-based molecules with tailored optoelectronic properties. Herein, we report the first synthesis of hexaarylborazines that, bearing ortho-substituted aryl moieties, extend threedimensionally. Using a one-pot protocol, we first form an electrophilic chloroborazole and then react it with an aryl lithium (ArLi). By selecting the appropriate ortho-substituent, we can guide the ArLi to add to the BN-core in a specific way, ultimately controlling the stereochemical outcome of the three-substitution reaction. Rationalization of the stereochemical model through computational analysis allowed us to show that when aryl lithium nucleophiles bearing rigid long-range ortho-substituents are used, i.e., stiff substituents. The ortho-substituent shields its side of the electrophilic B3N3 core, biasing the incoming ArLi to add anti at each addition step, forming the final tri-aryl borazine exclusively as cc-isomer. Leveraging this stereoselective approach, prototypical multichromophoric borazine derivatives were prepared, and we showcased how the stereochemical arrangement of these chromophores distinctly influences their redox behavior. This methodology paves the way for previously inaccessible borazines to serve as privileged precursors to transcend the conventional bidimensionality associated with graphenoid systems and pioneer the construction of new forms of three-dimensional C(sp2)-based architectures.

While the inclusion of synthetic polymers such as primary microplastics within personal care products have been widely restricted under EU/UK Law, water-soluble polymers (WSPs) have so far slipped the net of global chemical regulation despite evidence that these could be polluting wastewater effluents at concentrations greatly exceeding those of microplastics. Polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) represent WSPs with common industry and household uses, down-the-drain disposal and a direct route to wastewater treatment plants, conveying high risk of environmental leaching into freshwater ecosystems. The current study is the first investigating the impacts of predicted environmental concentrations of these WSPs on life-history traits of two freshwater species also constituting a disease model (fish - Poecilia reticulata and parasite - Gyrodactylus turnbulli). Single effects of WSPs on fish as well as their interactive effects with infection of the ectoparasite were determined over a 45-day exposure. Generally, WSPs reduced fish growth and increased routine metabolic rate of fish implying a depleted energetic budget, however these effects were dose, exposure time and polymer dependent. Parasitic infection alone caused a significant reduction in fish growth and enhanced fish routine metabolic rate. In contrast, a non-additive effect on metabolic rate was evident in fish experiencing simultaneous infection and WSP exposure, suggesting a protective effect of the two WSPs for fish also exposed to a metazoan ectoparasite. Off-host parasite survival was significantly lowered by both WSPs; however, parasite counts of infected fish also exposed to WSP were not significantly different from the control, implying more complex mechanisms may underpin this stressor interaction. Distinct detrimental impacts were inflicted on both organisms implying environmental leaching of WSPs may be causing significant disruption to interspecies interactions within freshwater ecosystems. Additionally, these results could contribute to sustainable development in industry, as we conclude PVA represents a less harmful alternative to PVP.

Ring size-dependent diastereoselective coordination of unsymmetrical diamines containing one azacyclic nitrogen and one exocyclic nitrogen to [(η5-C5Me5)MCl]+ cores where M = Rh, Ir and [Ru(η6-cymene)Cl]+ is reported herein. Total stereoselectivity was observed with the six- and seven-membered azacycles, whereas the five-derivative proved poorly selective. All complexes were active for transfer hydrogenation but showed no enantioselectivity with prochiral ketones.