Cellulose-based wet wipes undergo limited degradation in river environments.

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.

Is there a trend in inductive effect for different alkyl groups?

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 C NMR chemical shift diverges significantly from the calculated Hirshfeld charges, and we consider the latter to be a more reliable indicator of charge distribution.

Toxicity of the water-soluble polymer PVP is dependent on molecular weight and feed concentration for a freshwater model species.

Polyvinylpyrrolidone (PVP) is a synthetic water-soluble polymer (WSP) that does not readily biodegrade and has been detected in rivers in the mg L 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.

Expression of hyperconjugative stereoelectronic interactions in borazines.

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 coupling constant for the CH groups adjacent to the boron atoms are consistent with the presence of and interactions.

Alkyl groups in organic molecules are NOT inductively electron-releasing.

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.

Escape from Flatland: Stereoselective Synthesis of Hexa-aryl Borazines and their sp-Based 3D Architectures.

Borazine and its derivatives can be considered critical doping units for engineering hybrid C(sp)-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).

Predicting flushed wet wipe emissions into rivers.

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.

Ringing the Changes: Effects of Heterocyclic Ring Size on Stereoselectivity in [(η-CMe)RhCl], [(η-CMe)IrCl] and [Ru(η-cymene)Cl] Complexes of Chiral 3-Amino-1-Azacycles.

Ring size-dependent diastereoselective coordination of unsymmetrical diamines containing one azacyclic nitrogen and one exocyclic nitrogen to [(η-CMe)MCl] cores where M = Rh, Ir and [Ru(η-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.

One-Step Catalyst-Transfer Macrocyclization: Expanding the Chemical Space of Azaparacyclophanes.

In this paper, we report on a one-step catalyst-transfer macrocyclization (CTM) reaction, based on the Pd-catalyzed Buchwald-Hartwig cross-coupling reaction, selectively affording only cyclic structures. This route offers a versatile and efficient approach to synthesize aza[1]paracyclophanes (APCs) featuring diverse functionalities and lumens. The method operates at mild reaction temperatures (40 °C) and short reaction times (∼2 h), delivering excellent isolated yields (>75% macrocycles) and up to 30% of a 6-membered cyclophane, all under nonhigh-dilution concentrations (35-350 mM).

Detection of polyvinylpyrrolidone in Daphnia magna: Development of a refractive index quantification method for water-soluble polymers in aquatic organisms.

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 in wastewater and 0.

The impacts of synthetic and cellulose-based fibres and their associated dyes on fish hosts and parasite health.

Plastic pollution is now a ubiquitous feature of freshwater systems and the majority of this is fibrous. Here, we test the effects of plastic and cellulose-based fibres (polyester, cotton, and bamboo from commercial clothing) on fish host-parasite interactions using a freshwater fish host-parasite model system (guppy Poecilia reticulata-Gyrodactylus turnbulli). For uninfected fish, polyester exposure was associated with significantly higher mortality rates compared with the other two fibre types.

Water-soluble polymers: Emerging contaminants detected, separated and quantified by a novel GPC/MALDI-TOF method.

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.

A class of their own? Water-soluble polymer pollution impacting a freshwater host-pathogen system.

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).

Do flushed biodegradable wet wipes really degrade?

Consumer wet wipes sold as biodegradable and flushable have tripled in market size in the last decade (>$3 billion in 2022), spurred by concerns over their potential harmful impact. Whilst predominantly composed of cellulosic fibres such as cotton, rayon, or wood pulp, these have been found to persist in sewers and in the environment in near equal abundance to their 'synthetic' counterparts. This questions whether flushed biodegradable wet wipes really degrade.

Organometallic Platinum(II) Photosensitisers that Demonstrate Ligand-Modulated Triplet-Triplet Annihilation Energy Upconversion Efficiencies.

A series of 2-phenylquinoxaline ligands have been synthesised that introduce either CF or OCF electron-withdrawing groups at different positions of the phenyl ring. These ligands were investigated as cyclometalating reagents for platinum(II) to give neutral complexes of the form [Pt(C^N)(acac)] (in which C^N=cyclometalating ligand; acac=acetyl acetonate). X-ray crystallographic studies on three examples showed that the complexes adopt an approximate square planar geometry.

Simple Zn(ii) complexes for the production and degradation of polyesters.

Nine new complexes based on thioether appended iminophenolate (ONS) ligands have been prepared and fully characterized in solution by NMR spectroscopy. Solid-state structures were also obtained for seven complexes. In solution, all complexes were monomeric.

Boron-Nitrogen-Doped Nanographenes: A Synthetic Tale from Borazine Precursors.

In this work, a comprehensive account of the authors' synthetic efforts to prepare borazino-doped hexabenzocoronenes by using the Friedel-Crafts-type electrophilic aromatic substitution is reported. Hexafluoro-functionalized aryl borazines, bearing an ortho fluoride leaving group on each of the N- and B-aryl rings, was shown to lead to cascade-type electrophilic aromatic substitution events in the stepwise C-C bond formation, giving higher yields of borazinocoronenes than those obtained with borazine precursors bearing fluoride leaving groups at the ortho positions of the B-aryl substituents. By using this pathway, an unprecedented boroxadizine-doped PAH featuring a gulf-type periphery could be isolated, and its structure proven by single-crystal X-ray diffraction analysis.

Aluminium-catalysed isocyanate trimerization, enhanced by exploiting a dynamic coordination sphere.

Main-group metals are inherently labile, hindering their use in catalysis. We exploit this lability in the synthesis of isocyanurates. For the first time we report a highly active catalyst that trimerizes alkyl, allyl and aryl isocyanates, and di-isocyanates, with low catalyst loadings under mild conditions, using a hemi-labile aluminium-pyridyl-bis(iminophenolate) complex.

Fluorescent functionalised naphthalimides and their Au(i)-NHC complexes for potential use in cellular bioimaging.

A series of cationic, dihydroimidazolinium-functionalized 1,8-naphthalimide fluorophores have been isolated as their hexafluorophosphate salts, [HL]PF. These pro-ligands react with [AuCl(tht)] in the presence of base to form N-heterocyclic carbene (NHC) complexes, [AuCl(L)]. Two X-ray structures represent a pro-ligand and complex pairing: the latter reveals the two-coordinate linear geometry of the NHC-Au(i) species, as well as intermolecular interactions supported by both ligand π-π stacking and a weak aurophilic interaction of 3.

Synthesis and characterisation of fluorescent aminophosphines and their coordination to gold(i).

Three novel fluorescent aminophosphine ligands have been synthesised that incorporate napthyl (L1), pyrenyl (L2) and anthraquinone (L3) chromophores into their structures. The ligands react with [AuCl(tht)] (tht = tetrahydrothiophene) to give neutral complexes of the form [AuCl(L1-3)]. Solid state, X-ray crystallographic data was obtained for the anthraquinone derivative, [AuCl(L3)], and showed a distorted linear coordination geometry at Au(i).

Shaping and enforcing coordination spheres: probing the ability of tripodal ligands to favour trigonal prismatic geometry.

We report two tripodal frameworks, mono(2,2'-bipyrid-6-yl)bis(2-pyridyl)methanol () and bis(2,2'-bipyrid-6-yl)mono(2-pyridyl)methanol () which have one and two bipyridyl arms, respectively. Both ligands form complexes with the first row transition metals. Both ligands appear to overcome the steric strain involved in twisting the ligand to produce an octahedral complex and the solid state structures in general show more octahedral character than complexes of the related ligand, tris(2,2'-bipyrid-6-yl)methanol ().

Chromophore-labelled, luminescent platinum complexes: syntheses, structures, and spectroscopic properties.

Ligands based upon 4-carboxamide-2-phenylquinoline derivatives have been synthesised with solubilising octyl hydrocarbon chains and tethered aromatic chromophores to give naphthyl (), anthracenyl () and pyrenyl () ligand variants, together with a non-chromophoric analogue () for comparison. (1)H NMR spectroscopic studies of the ligands showed that two non-interchangeable isomers exist for and while only one isomer exists for and . Supporting DFT calculations on suggest that the two isomers may be closely isoenergetic with a relatively high barrier to exchange of ca.

Near-IR luminescent lanthanide complexes with 1,8-diaminoanthraquinone-based chromophoric ligands.

Three new chromophoric anthraquinone-based multidentate ligands have been synthesised in a step-wise manner from 1,8-dichloroanthraquinone. The ligands each comprise two dipicolyl amine units and react with trivalent lanthanide ions to form monometallic complexes of the form [Ln(L)](OTf)3 as indicated by MS studies and elemental analyses. Supporting DFT studies show that the monometallic species are highly favoured (>1000 kJ mol(-1)) over the formation of a 2 : 2 dimetallic congener.

Basic knee arthroscopy part 4: chondroplasty, meniscectomy, and cruciate ligament evaluation.

Knee arthroscopy is an important diagnostic and therapeutic tool in the management of disorders of the knee. In a series of 4 articles, the basics of knee arthroscopy are reviewed. In this article (part 4), the basics of operative knee arthroscopy are reviewed including chondroplasty and meniscectomy.