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Health risks are often overlooked when the short-term consequences are not immediately apparent. During restoration work, cleaning actions can generate particles that pose health risks to workers through inhalation. This is particularly true in the case of asbestos fibres that might be spread out from the laser cleaning of buildings or heritage artifacts made of stone, such as serpentinite and other ultramafic rocks, that have a high probability of containing asbestos (e.g., chrysotile, tremolite asbestos, actinolite asbestos). To show workers the importance of wearing proper protection to prevent health injuries, several serpentinite samples, ascertained to contain asbestos minerals by specific investigations, have been laser ablated using ad hoc modified equipment in order to collocate a HEPA filter prone to collect all dust emitted during ablation. The powder deposited on the surface of these filters after laser ablation was analyzed, by Powder X -ray Diffraction (PXRD), Transmission Electron Microscopy combined with Energy Dispersive Spectroscopy (TEM/EDS), micro-Raman spectroscopy (μ-Raman) and Fourier-transform infrared spectroscopy (FTIR/ATR). The results confirmed the presence of asbestos fibres during the laser ablation of rocks containing Naturally Occurring Asbestos (NOA), emphasizing the importance of wearing appropriate personal protective equipment (PPE) during these procedures. Noteworthy, approximately 33 % of the analyzed fibres met the WHO criteria in size for respirable fibres. Furthermore, through our experiments, we also demonstrated that using tools that integrate filters into working tools would definitively further decrease the risk of fibres inhalation to workers., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The effects exerted by new bioactive acylpyrazolonate Ag(I) derivatives of the general formula [Ag(QPy,CF3)(R-Im)] containing different substituents on the imidazole (R-Im) ancillary ligands and the natural plasticizer castor oil when both are added to the ethylcellulose (EC) biopolymer in the preparation of thin films as potential active food packaging materials are presented. The Ag(I) complexes [Ag(QPy,CF3)(Bn-Im)] and [Ag(QPy,CF3)(Bu-Im)], having benzyl and butyl substituents, whose single crystal molecular structures are reported, have proved to be highly compatible for efficient incorporation between the EC polymer and the hydrophobic plasticizer chains, giving rise, even at low concentrations, to homogeneous, robust and elastic films. The concomitant presence of these Ag(I) complexes and castor oil in the polymer EC matrix gives rise to thin films with improved antibacterial activity against Escherichia coli ( E. coli ) as a model of Gram-negative bacterial strains when compared to the non-plasticized ones, with very low Ag(I) migration in the three food simulants used (distilled water, ethanol 10% v/v and acetic acid 3% v/v) under two assay conditions (70 °C for 2 h and 40 °C for 10 days).

Bio-active ethylcellulose (EC) polymeric films have been obtained by incorporating curcumin (curc) and Ag(I)-based compounds, known for their antioxidant and antimicrobial activity, respectively, within the polymeric matrix. The recently reported Ag(I) coordination polymer, in both its structural forms (α-[(bpy)Ag(OTf)] ∞ and β-{[(bpy)Ag][OTf]} ∞ ), and the [(bpy)Ag(OTf)] ∞ -curc polymeric co-crystal (bpy=2,2'-bipyridine; OTf=trifluoromethanesulfonate) have been selected as Ag(I) species. The hybrid composite films have been prepared through the simple solvent casting method and characterized through Powder X-Ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM), UV-vis spectroscopy. The deep investigation of the film samples highlighted the non-inert behaviour of EC towards these specific active ingredients. Antimicrobial tests showed that EC films embedding the Ag(I)-based compounds present good antimicrobial performance, in particular against Staphylococcus aureus, used as a model of Gram-positive bacteria. In addition, Silver migration tests, performed on the Ag(I)-incorporating EC films, evidenced low values of silver release particularly in the case of the EC films incorporating [(bpy)Ag(OTf)] ∞ -curc., (© 2024 Wiley-VCH GmbH.)

Many efforts have been made in the last few decades to selectively transport antitumor agents to their potential target sites with the aim to improve efficacy and selectivity. Indeed, this aspect could greatly improve the beneficial effects of a specific anticancer agent especially in the case of orphan tumors like the triple negative breast cancer. A possible strategy relies on utilizing a protective leaving group like alizarin as the Pt(II) ligand to reduce the deactivation processes of the pharmacophore enacted by Pt resistant cancer cells. In this study a new series of neutral mixed-ligand Pt(II) complexes bearing alizarin and a variety of diamine ligands were synthesized and spectroscopically characterized by FT-IR, NMR and UV-Vis analyses. Three Pt(II) compounds, i.e. , 2b, 6b and 7b, emerging as different both in terms of structural properties and cytotoxic effects (not effective, 10.49 ± 1.21 μM and 24.5 ± 1.5 μM, respectively), were chosen for a deeper investigation of the ability of alizarin to work as a selective carrier. The study comprises the in vitro cytotoxicity evaluation against triple negative breast cancer cell lines and ESI-MS interaction studies relative to the reaction of the selected Pt(II) complexes with model proteins and DNA fragments, mimicking potential biological targets. The results allow us to suggest the use of complex 6b as a prospective anticancer agent worthy of further investigations.

Asbestos fibers act as complex crystal-chemical reservoirs susceptible of releasing potentially toxic elements (such as ions impurities) into the lung cellular environment during permanency and dissolution. To comprehend the exact pathological mechanisms that are triggered upon inhalation of asbestos fibers, in vitro studies on possible interactions between the mineral and the biological system have been carried out mostly by using natural asbestos. However, this latter comprises intrinsic impurities such as Fe 2+ /Fe 3+ and Ni 2+ ions, and other eventual traces of metallic pathogens. Furthermore, often, natural asbestos is characterized by the co-presence of several mineral phases, fiber dimensions of which are randomly distributed in width and in length. For these reasons, it is albeit challenging to precisely identify toxicity factors and to define the accurate role of each factor in the overall pathogenesis of asbestos. In this regard, the availability of synthetic asbestos fibers with accurate chemical composition and specific dimensions for in vitro screening tests would represent the perfect tool to correlate asbestos toxicity to its chemico-physical features. Herein, to palliate such drawbacks of natural asbestos, well-defined Ni-doped tremolite fibers were chemically synthesized in order to offer biologists adequate samples for testing the specific role of Ni 2+ in asbestos toxicity. The experimental conditions (temperature, pressure, reaction time and water amount) were optimized to produce batches of asbestos fibers of the tremolite phase, with uniformly distributed shape and dimensions and a controlled content of Ni 2+ metal ions.

The synthesis and design of two-dimensional supramolecular assemblies with specific functionalities is one of the principal goals of the emerging field of molecule-based electronics, which is relevant for many technological applications. Although a large number of molecular assemblies have been already investigated, engineering uniform and highly ordered two-dimensional molecular assemblies is still a challenge. Here we report on a novel approach to prepare wide highly crystalline molecular assemblies with tunable structural properties. We make use of the high-reactivity of the carboxylic acid functional moiety and of the predictable structural features of non-polar alkane chains to synthesize 2D supramolecular assemblies of 4-(decyloxy)benzoic acid (4DBA;C[Formula: see text]H[Formula: see text]O[Formula: see text]) on a Au(111) surface. By means of scanning tunneling microscopy, density functional theory calculations and photoemission spectroscopy, we demonstrate that these molecules form a self-limited highly ordered and defect-free two-dimensional single-layer film of micrometer-size, which exhibits a nearly-freestanding character. We prove that by changing the length of the alkoxy chain it is possible to modify in a controlled way the molecular density of the "floating" overlayer without affecting the molecular assembly. This system is especially suitable for engineering molecular assemblies because it represents one of the few 2D molecular arrays with specific functionality where the structural properties can be tuned in a controlled way, while preserving the molecular pattern., (© 2023. The Author(s).)

Incorporating carbon dots (CDs) into chiral self-assemblies will endow the system with intriguing optoelectronic, catalytic, and chiroptical activities. Utilization of chiral substituents to rationally manipulate chiral self-assembly of the CDs, however, remains a major challenge. In this work, cholesteryl monoprotected ethylene diamine was used as a precursor to synthesize CDs with a cholesteryl periphery. The rigid, apolar, and chiral cholesteryl facilitates the polarity-sensitive self-assembly of CDs in organic solvents, showing circularly polarized luminescence (CPL) with dissymmetry g -factor at 10 -3 grade. Temperature-variable characterizations suggested the formation of thermotropic liquid crystals within a wide temperature range driven by the interdigitation of cholesteryl segments, which further anchor the graphitic CD cores into tetragonal and cubic arrays. Self-assembly in a solvent-free state arouses sufficient chirality transfer and boosted the g -factors to 10 -2 order of magnitude. This work unveils multiple and chiral self-assembly of CDs controlled by the cholesteryl substituents, exhibiting variable architectures and tunable CPL.

Mono- N -alkylated primary oxalamide derivatives with different sized branched alkyl tail-groups were excellent low molecular weight gelators for a variety of different organic solvents with different polarities and hydrogen-bonding abilities. Solvent-gelator interactions were analyzed using Hansen solubility parameters, while 1 H NMR and FTIR spectroscopy were used to probe the driving forces for the supramolecular gelation. The molecular structures of the twin tail-groups did not significantly affect the supramolecular gelation behavior in different solvents. However, for select solvents, the molecular structures of the tail-groups did have a significant effect on gel properties such as the critical gelator concentration, thermal stability, gel stiffness, gel strength, network morphology, and molecular packing. Finally, metabolic activity studies showed that the primary alkyl oxalamide gelators had no effect on the metabolic activity of mouse immune cells, which suggests that the compounds are not cytotoxic and are suitable for use in biomedical applications.

A series of novel cationic curcumin-based Pt(II) complexes with neutral (N^N) ligands and triflate anions as counterions, [(N^N)Pt(curc)]CF 3 SO 3 , 1-4, were synthesised and fully characterised. The antioxidant radical scavenging activity of complexes 1-4 was measured spectrophotometrically using DPPH as the internal probe. Computational strategies have been exploited to ascertain the mechanism of antioxidant action of curcumin (H(curc)) and its Pt(II) complexes. Finally, compounds 1-4 were tested in vitro for their growth inhibitory activity against two bacteria ( Staphylococcus aureus and Escherichia coli ) by the disk diffusion technique at different Pt(II) complex solution concentrations. The effect of the complexation of H(curc) was investigated.

Artificial light-harvesting systems (ALHSs), which are closely related to Förster resonance energy transfer (FRET), are among the most attractive scientific topics during the past few decades. Specifically, binary ALHSs that are composed of a fluid donor and acceptor have a simplified composition and high number density of the donor units. However, largely due to the difficulty in obtaining a fluid donor, investigation of these systems is still quite limited, especially for the ionic systems. Herein, we report a new type of binary ALHS using an ionic naphthalimide (NPI) derivative as a donor, which shows greatly improved photoluminescence for its bicontinuous liquid structure. When blending with an acceptor such as rhodamine 6G or trans -4-[4-(dimethylamino)styryl]-methylpyridinium iodide, efficient FRET was confirmed by both experimental results and molecular dynamics simulations, with an energy transfer efficiency up to ∼90%. Tunable color, including white-light emission, was achieved by tuning the acceptor/donor ratio, opening the door for a variety of applications such as light-emitting diodes and photoluminescent inks.

The improvement of the antioxidant and antimicrobial activities of chitosan (CS) films can be realized by incorporating transition metal complexes as active components. In this context, bioactive films were prepared by embedding a newly synthesized acylpyrazolonate Zn(II) complex, [Zn(Q PhtBu ) 2 (MeOH) 2 ], into the eco-friendly biopolymer CS matrix. Homogeneous, amorphous, flexible, and transparent CS@Zn n films were obtained through the solvent casting method in dilute acidic solution, using different weight ratios of the Zn(II) complex to CS and characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), Raman, and scanning electron microscopy (SEM) techniques. The X-ray single-crystal analysis of [Zn(Q PhtBu ) 2 (MeOH) 2 ] and the evaluation of its intermolecular interactions with a protonated glucosamine fragment through hydrogen bond propensity (HBP) calculations are reported. The effects of the different contents of the [Zn(Q PhtBu ) 2 (MeOH) 2 ] complex on the CS biological proprieties have been evaluated, proving that the new CS@Zn n films show an improved antioxidant activity, tested according to the DPPH method, with respect to pure CS, related to the concentration of the incorporated Zn(II) complex. Finally, the CS@Zn n films were tried out as antimicrobial agents, showing an increase in antimicrobial activity against Gram-positive bacteria ( Staphylococcus aureus ) with respect to pure CS, when detected by the agar disk-diffusion method., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Policastro, Giorno, Scarpelli, Godbert, Ricciardi, Crispini, Candreva, Marchetti, Xhafa, De Rose, Nucera, Barberi, Castriota, De Bartolo and Aiello.)

Platinum compounds cytotoxicity is strictly related to their ability to be converted into active mono- and di-aquated species and consequently to the replacement of labile ligands by water molecules. This activation process makes the platinum center prone to nucleophilic substitution by DNA purines. In the present work, quantum mechanical density functional theory (DFT) computations and experimental investigations were carried out in order to shed light on the relationship between the internalization, aquation, and DNA binding of two isostructural anionic theranostic complexes previously reported by our group, NBu 4 [(PhPy)Pt(Aliz)], 1 ( IC 50 1.9 ± 1.6 μM), and NBu 4 [(PhPy)Pt(BrCat)], 2 ( IC 50 52.8 ± 3.9 μM). Cisplatin and a neutral compound [(NH 3 ) 2 Pt(Aliz)], 3 , were also taken as reference compounds. The computed energy barriers and the endergonicity of the hydrolysis reactions showed that the aquation rates are comparable for 1 and 2 , with a slightly higher reactivity of 1 . The second hydrolysis process was proved to be the rate-determining step for both 1 and 2 , unlike for compound 3 . The nucleophilic attack by the N7 site of guanine to both mono- and di-aquated forms of the complexes was computationally investigated as well, allowing to rationalize the observed different cytotoxicity. Computational results were supported by photostability data and biological assays, demonstrating DNA as the main target for compound 1 .

A new series of 5-alkylamido isophthalic acid (ISA) derivatives with varying single and twin alkyl chain lengths were designed and synthesized as potential supramolecular organogelators. 5-alkylamido ISAs with linear or branched alkyl tail-groups of different lengths were effective gelators for low polarity solvents. In particular, among the presented series, a derivative with a branched, 24 carbon atom tail-group behaves as a "supergelator" with up to twenty organic solvents forming gels that are highly stable over time. The gelation behavior was analyzed using Hansen solubility parameters, and the thermal stability and viscoelastic properties of select gels were characterized. Microscopy, spectroscopy, powder X-ray diffraction, and computer modeling studies were consistent with a hierarchical self-assembly process involving the formation of cyclic H-bonded hexamers via the ISA carboxylic acid groups, which stack into elementary fibers stabilized by H-bonding of the amide linker groups and π-π stacking of the aromatic groups. These new nanomaterials exhibited potential for the phase-selective gelation of oil from oil-water mixtures and dye uptake from contaminated water. The work expands upon the design and synthesis of supramolecular self-assembled nanomaterials and their application in water purification/remediation.

Chiral assembly of metal nanoparticles (NPs) into complex superstructures has been widely studied, but their formation mechanisms still remain mysterious due to the lack of precise structural information from the metal-organic interface to metallic kernel. As "molecular models" of metal NPs, atomically precise metal nanoclusters (NCs) used in the assembly of a macroscale superstructure will provide details of microscopic structure for deep understanding of such highly sophisticated assemblies; however, chiral superstructures have not been realized starting from achiral metal NCs with atomic precision. Herein, we report the supramolecular assembly of a water-soluble silver NC ((NH 4 ) 9 [Ag 9 (mba) 9 ], H 2 mba = 2-mercaptobenzoic acid, abbreviated as Ag 9 -NCs hereafter) into chiral hydrogels induced by the coordination of secondary metal ions. Single crystal X-ray diffraction reveals the triskelion-like structure of Ag 9 -NCs with a pseudochiral conformation caused by special arrangement of the peripheral mba 2- ligands. The enantioselective orientation of the peripheral carboxyl group facilitates the assembly of Ag 9 -NCs into nanotubes with a chiral cubic ( I *) lattice when coordinating to Ba 2+ . The nanotubes can further intertwine into one-dimensional chiral nanobraids with a preferred left-handed arrangement. These multiple levels of chirality can be tuned by drying, during which the I * phase is missing but the chiral entanglement of the nanotubes is enhanced. Through the gelation of atomically precise, achiral NCs coordination of secondary metal ions, chiral amplification of superstructures was realized. The origination of the chirality at different length scales was also discussed.

The synthesis and the electrochemical, photophysical, structural, and photoconductive properties of three new heteroleptic Pd(II) complexes with various 3',5'- disubstituted-2-(2'-pyridil) pyrroles H(N^N) as coordinated ligands are reported. The coordination of the metal center was completed by a functionalized Schiff base H(O^N) used as an ancillary ligand. The [(N^N)Pd(O^N)] complexes showed highly interesting photoconductive properties which have been correlated to their electronic and molecular structures. Theoretical density functional theory (DFT) and time-dependent DFT calculations were performed, and the results were confronted with the organization in crystalline phase, allowing to point out that the photoconductive properties are mainly a consequence of an efficient intramolecular ligand-to-metal charge transfer, combined to the proximity between the central metal and the donor moieties in the solid-state molecular stacks. The reported results confirm that these new Pd(II) complexes form a novel class of organometallic photoconductors with intrinsic characteristics suitable for molecular semiconductors applications.

Over the years, the need for the synthesis of biodegradable materials has facilitated the drift of the asphalt industry towards eco-sustainable and cost-effective production of road pavements. The principal additives in the asphalt industry to improve the performance of road pavements and increase its lifespan are majorly rheological modifiers, adhesion promoters and anti-oxidant agents. Rheological modifiers increase physico-chemical properties such as transition temperature of asphalt binder (bitumen), adhesion promoters increase the affinity between binder and stone aggregates while anti-oxidant agents reduce the effects of oxidation caused by exposure to air, water and other natural elements during the production of asphalt pavements. In this study, we tested the effectiveness of a food grade bio-additive on these three aforementioned properties. We also sought to hypothesize the mechanisms by which the additive confers these desired features on bitumen. We present this study to evaluate the effects of turmeric, a food-based additive, on bitumen. The study was conducted through dynamic shear rheology (DSR), atomic force microscopy, scanning electron microscopy (SEM) and boiling test analysis.

A nanostructured hybrid material consisting of TiO 2 nanoparticles grown and stabilized on graphene oxide (GO) platelets, was synthesized and tested as nanofiller in a polymeric matrix of sulfonated polysulfone (sPSU) for the preparation of new and low-cost nanocomposite electrolytes for proton exchange membrane fuel cell (PEMFC) applications. GO-TiO 2 hybrid material combines the nanoscale structure, large interfacial area, and mechanical features of a 2D, layered material, and the hygroscopicity properties of ceramic oxides, able to maintain a suitable hydration of the membrane under harsh fuel cell operative conditions. GO-TiO 2 was synthetized through a new, simple, one-pot hydrothermal procedure, while nanocomposite membranes were prepared by casting using different filler loadings. Both material and membranes were investigated by a combination of XRD, Raman, FTIR, thermo-mechanical analysis (TGA and Dynamic Mechanical Analysis) and SEM microscopy, while extensive studies on the proton transport properties were carried out by Electrochemical Impedance Spectroscopy (EIS) measurements and pulse field gradient (PFG) NMR spectroscopy. The addition of GO-TiO 2 to the sPSU produced a highly stable network, with an increasing of the storage modulus three-fold higher than the filler-free sPSU membrane. Moreover, the composite membrane with 3 wt.% of filler content demonstrated very high water-retention capacity at high temperatures as well as a remarkable proton mobility, especially in very low relative humidity conditions, marking a step ahead of the state of the art in PEMs. This suggests that an architecture between polymer and filler was created with interconnected routes for an efficient proton transport.

Widespread environmental contamination from chlorpyrifos (CPF) is well acknowledged and has led to the proposal to ban or limit its use in agricultural and domestic, within the regulatory context of both America and Europe. Furthermore, great concerns arise as to whether exposure to CPF represents a potential risk to human health. In the present study, by subjecting the goldfish model to three environmentally realistic concentrations of CPF (1, 4, and 8 μg/L) for 96 h, we demonstrated that this pesticide has the potential to induce severe morphological, ultrastructural and functional alterations in gills, even at very low concentrations. The degree of pathological effects was dose-dependent, and the main morphological alterations recorded were: regression of interlamellar cellular mass (ILCM), hypertrophy, and hyperplasia of epithelial cells, degeneration of both chloride cells and pillar cells. CPF exposure resulted in a decrease of Na + /K + -ATPase expression and the induction of iNOS, as revealed by immunohistochemical analysis. In order to determine the overall toxicity of CPF, we also investigated the recovery capability of goldfish gills following a period of 7 days in pesticide-free water. Our results clearly showed that there exists a threshold of CPF dose below which the effects on gills are reversible and beyond which the ability of gills to recover their typical features is completely lost. The information presented in this paper emphasises the importance of evaluating the recovery ability of organisms after chemical input and enhances our knowledge of the potential hazard of organophosphorus pesticides (OPs) on freshwater ecosystems., Competing Interests: Declaration of competing interest Authors declare that the research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Neutral cyclometalated Ir(iii) complexes of general formula [Ir(ppy)2(O^O)squi], where ppy = 2-phenylpyridine and (O^O)squi = TBC (tetrabromocatechol) or TCC (tetrachlorocatechol) in their semiquinone (squi) monoanionic redox state, were synthesized by chemically oxidizing the anionic parent complexes NBu4[Ir(ppy)2(O^O)cat], in which (O^O)cat represents the corresponding ancillary dioxolene ligand in its dianionic catecholate (cat) redox state. This chemical oxidation leads to the modification of both the photophysical and the magnetic properties of the complexes. While the NBu4[Ir(ppy)2(O^O)cat] complexes are diamagnetic (D) and yellow-orange solids, the corresponding oxidized complexes [Ir(ppy)2(O^O)squi] display paramagnetic (P) properties and are characterized by a dark-green color. The conversion between the two forms (squi vs. cat) is electrochemically and chemically fully reversible. Indeed, the anionic NBu4[Ir(ppy)2(O^O)cat] complexes are quantitatively restored by chemical reduction of the neutral [Ir(ppy)2(O^O)squi] parents. These complexes therefore represent interesting redox based switches between multi-parameter states since they allow switching from a neutral paramagnetic to an anionic diamagnetic form together with a significant change in chromicity. Taking advantage of the significant color difference between the oxidized and the reduced form, an electrochromic cell was prepared with [Ir(ppy)2(TBC)squi] and its spectroelectrochemical properties are reported.

The ability of Nile Red to self-assemble into supramolecular packings on Au(111) was studied using scanning tunneling microscopy and modeled through theoretical semiempirical calculations. At both submonolayer (sub-ML) and ML coverages, two distinct molecular packings, that is, four-leaf clover and dense chain, were observed, both weakly interacting with the underlying metal surface. Theoretical calculations suggested that the dipole moment plays a subtle role in both molecular assemblies, held together by hydrogen bonds between the Nile Red molecules. Furthermore, although both molecular assemblies were observed in as-deposited samples, a mild thermal annealing caused the transition from the four-leaf clover to the dense-chain packing, pointing out the greater stability of the dense-chain configuration. The study further emphasized how the established interactions between the Nile Red molecules are strongly influenced by the surrounding environment.

A series of electropolymerizable cyclometallated Ir III complexes were synthesized and their electrochemical and photophysical properties studied. The triphenylamine electropolymerizable fragment was introduced by using triphenylamine-2-phenylpyridine and, respectively, triphenylamine-benzothiazole as cyclometalated ligands. The coordination sphere was completed by two differently substituted β-ketoiminate ligands deriving from the condensation of acetylacetone or hexafluoroacetylacetone with para-bromoaniline. The influence of the -CH 3 /-CF 3 substitution to the electrochemical and photophysical properties was investigated. Both complexes with CH 3 substituted β-ketoiminate were emissive in solution and in solid state. Highly stable films were electrodeposited onto ITO coated glass substrates. Their emission was quenched by electron trapping within the polymeric network as proven by electrochemical studies. The -CF 3 substitution of the β-ketoiminate leads instead to the quenching of the emission and inhibits electropolymerization., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Lead is one of the most alarming toxic pollutants for the environment due to its acute toxicity and high bioaccumulation tendency. Despite legislative efforts, world lead production has more than doubled since the early 1970s to 2016. Due to extensive exploitation and human activity, the coastal and estuarine regions belong to marine environments that are mostly and more rapidly deteriorated by pollutants including lead. A limited number of studies examined the effects of lead in fishes, compared to other aquatic models and even fewer studies have been dedicated to seawater fishes especially regarding Pb adsorption and accumulation in specific organs. Fish gills, key compartments involved in several crucial functions such as gas exchange, osmoregulation, and excretion, are also the organs in which Pb is mainly accumulated. Herein, we investigated the morphofunctional and ultrastructural modifications in the gills of a marine teleost (Thalassoma pavo) after acute exposure (48, 96, 192 h) to three lead concentrations. We showed that pathological alterations can be detected in all the examined samples. The most common modifications observed were: the curling of the lamellae and the dilation of their apical tips, the lamellar edema, the proliferation and the hypertrophy of CCs, the progressive epithelial disorganization with detachment of the epithelium from connective tissue. This study also demonstrates that there is a weak influence on the expression pattern of Na + /K + -ATPase and AQP3 biomarker enzymes while high metallothioneins expression has been observed. The described alterations may adversely affect gas exchange and ionic balance, with a long chain of cascading effects. This is the first evidence of the effects exerted by lead on gills of seawater fishes that highlights the harmful properties of this metal, even at low concentration., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Novel anionic cyclometalated Pt(ii) square-planar complexes NBu4[(C^N)PtII(S^S)], containing 2-phenylpyridine H(PhPy), 2-(2,4-difluorophenyl)-pyridine H(F2PhPy) and benzo[h]quinoline H(Bzq), respectively, as a cyclometalated ligand and the dianionic 1,2-benzenedithiolate (Thio)2- fragment as an (S^S) ligand, were synthesised. By the simple addition of an equivalent of (Thio)2- to the NBu4[(C^N)PtII(Thio)] complexes, octahedral anionic NBu4[(C^N)PtIV(Thio)2] analogues were obtained, representing, to the best of our knowledge, the first examples of Pt(iv) anionic cyclometalated complexes. The molecular structures of the obtained complexes in the case of the NBu4[(Bzq)PtII(Thio)] and the NBu4[(Bzq)PtIV(Thio)2] complexes were confirmed by single crystal X-ray diffraction analysis. Furthermore, the electrochemical and photophysical properties of the two series of Pt(ii) and Pt(iv) newly synthesised complexes were studied and DFT and TD-DFT calculations were performed in order to comprehensively investigate the displayed behaviour. All Pt(ii) and Pt(iv) complexes show intense luminescence in the solid state, with remarkable enhancement of the emission quantum yields, proving to be excellent examples of aggregation-induced emission systems.

The preparation and characterization of a new metallogelator based on the Ir III discrete cyclometalated complex [(ppy) 2 Ir(bpy)](CH 3 CH 2 OCH 2 CO 2 ) are reported, where H(ppy) is 2-phenylpiridine and bpy is 2,2'-bipyridine, which is used as an ancillary ligand. The compound is able to self-assemble in water in a range of concentrations between 3 % and 6 % w/w, creating a luminescent ordered supramolecular gel. The gel and xerogel architectures were investigated through polarized optical microscopy (POM), SEM and TEM microscopies coupled with powder X-ray diffraction. The gel supramolecular organization is characterized by columnar tetragonal strands, already present at high dilution conditions, of cations surrounded by counteranions. These strands, in turn, are self-assembled in an oblique columnar cell upon gelification. The xerogel thin films obtained upon complete dehydration maintained the gel supramolecular order and can be used as a precursor for the preparation of nanostructured IrO 2 thin films., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two series of novel NBu 4 + [(C^N)Pt(O^N)] and NBu 4 [(C^N)Pt(O^O)]) are incorporated as testing examples of cyclometallating ligands 2-phenylpyridine (PhPy), 2-(2,4-difluorophenyl)-pyridine (F 4 PhPy) and 2-thienylpyridine (ThPy), and a benzo[h]quinoline (Bzq) fragment. All complexes display a square-planar coordination sphere, wherein the "(C^N)Pt" fragment is completed either by an O^N orotate (Ort) or an O^O tetrabromocatecholate (Cat) ligand. The HOMO and LUMO levels of all complexes were estimated by cyclic voltammetry and a comprehensive electrochemical and photophysical study was performed. The new complexes are emissive in solution at 298 K and the NBu 2 PhPy) and 2-thienylpyridine (ThPy), and a benzo[h]quinoline (Bzq) fragment. All complexes display a square-planar coordination sphere, wherein the "(C^N)Pt" fragment is completed either by an O^N orotate (Ort) or an O^O tetrabromocatecholate (Cat) ligand. The HOMO and LUMO levels of all complexes were estimated by cyclic voltammetry and a comprehensive electrochemical and photophysical study was performed. The new complexes are emissive in solution at 298 K and the NBu 4 [(ThPy)Pt(Ort)] complex displays good photosensitizing properties (Φ = 28% in deaerated solution vs. Φ = 1.4% in the presence of O 2 [(C^N)Pt(Ort)] and NBu 4 [(C^N)Pt(Cat)] complexes are highly luminescent in the solid state (emission quantum yields from 10 to 85%). Remarkably, the square-planar Pt(ii) anionic complexes showed an important increase in luminescence quantum yields on changing from the dilute solution to the solid state (the most significant from 0.13% to 85% for the NBu 4 [(C^N)Pt(Cat)] complexes are highly luminescent in the solid state (emission quantum yields from 10 to 85%). Remarkably, the square-planar Pt(ii) anionic complexes showed an important increase in luminescence quantum yields on changing from the dilute solution to the solid state (the most significant from 0.13% to 85% for the NBu 4 [(PhPy)Pt(Ort)] complex, an ideal candidate as an active species for LEECs).

The synthesis and photophysical characterization of a new family of luminescent water-soluble ionic iridium(iii) complexes of the general formula [(ppy) 2 Ir(bpy)]X are reported. The Ir(iii) complexes incorporate a cyclometalated 2-phenylpyridine (ppy), the ancillary ligand 2,2'-bipyridyl (bpy) and different counterions (X - = EtO - , OH - , EtOCH 2 CO 2 - , MeOCH 2 CO 2 - ). These complexes were obtained starting from the cyclometalated Ir(iii) chloro-bridged dimer [(ppy) 2 Ir(μ-Cl)] 2 , for the first time synthesized through a new microwave assisted synthetic procedure, and subsequently converted into the corresponding hydroxy-bridged dimer [(ppy) 2 Ir(μ-OH)] 2 . The latter was eventually used as a sole reagent for the synthesis of all the reported complexes by simply varying the nature of the reaction solvent from water to alcohols and glycol ethers. This study demonstrates the versatility of the [(ppy) 2 Ir(μ-OH)] 2 complex as a precursor to water soluble ionic Ir(iii) complexes. Indeed, [(ppy) 2 Ir(μ-OH)] 2 has shown its peculiar chemical reactivity due to both a strong base character and an unexpected oxidative ability towards the alcoholic function of glycol ethers. All the synthesized complexes exhibit, in water solution, an orange emission centred at 606 nm. Moreover, all complexes display the ability to give rise to gel phases in water upon increasing their concentration, and the photophysical study evidenced the various interactions governing the gelification process. The water-solubility of these new luminescent Ir(iii) complexes makes them potentially useful in bio-related systems.

Homogeneous thin films of controlled thickness obtained from cyclometalated complexes of general formula [(C(∧)N)M(O(∧)N)], where M = Pd(II) or Pt(II), H(C(∧)N) = 2-phenylpyridine and, respectively, 2-thienylpyridine and H(O(∧)N) = a triphenylamine functionalized Schiff base, have been deposited by oxidative electropolymerization. The films have been electrochemically and morphologically characterized. The metallopolymeric thin films present stable reversible redox behavior and typical cauliflower-like textures in agreement with a nucleation-growth electropolymerization mechanism. However, the film growth is greatly influenced by the nature of the metal center, with a higher tendency of the Pt complexes to promote the 3D growth. Furthermore, a complete spectroelectrochemical study has been performed on electrodeposited films showing near-IR absorption in the oxidized state, high contrast ratios (up to 65%) and low response times.

The complete characterization of novel electropolymerizable organometallic complexes is presented. These are newly synthesized cyclometalated complexes of general formula (PPy)M(O ∧ N)(n) (H(PPy) = 2-phenylpyridine, M = Pd(II) or Pt(II), H(O ∧ N)(n) = Schiff base). Polymeric thin films have been obtained from these complexes by electropolymerization of the triphenylamino group grafted onto the H(O ∧ N)(n) ancillary ligand. The redox behavior and the photoconductivity of both of the monomers (PPy)M(O ∧ N)(n) and the electropolymerized species have been investigated. The polymeric films of (PPy)M(O ∧ N)(n) have shown a very significant enhancement of photoconductivity when compared to their monomeric amorphous counterparts. The high stability of the obtained films strongly suggests that electropolymerization of cyclometalated complexes represents a viable deposition technique of quality thin films with improved photoconduction properties, hence opening the door to a new class of materials with suitable properties for optoelectronic applications.

Two anionic iridium complexes [(R-ppy)2Ir(O^N)]TBA with R-ppy = 2-phenylpyridine or 4,5'-dimethyl-2-phenylpyridine, O^N = dianionic form of orotic acid and TBA = tetrabutylammonium have been synthesised and fully characterised by UV-Vis, emission, IR, NMR and cyclic voltammetric studies. These cyclometallated luminescent complexes containing a dianionic bidentate ancillary ligand show bright emission (60-70% PLQY) with maxima in the green region of the visible spectrum. Coupled with the ionic iridium complexes [(ppy)2Ir(N^N)]X, where N^N = 2-picolylamine or 2,2'-bipyridyl, and X = Cl(-) or CH3CO2(-), a series of new soft salts of general formula [(ppy)2Ir(N^N)][(R-ppy)2Ir (O^N)] have been obtained and fully characterized, with enhanced luminescent properties up to ca. 80% of phosphorescence quantum yields.

The incorporation of a rigid core, formed by a cyclopalladated azobenzene fragment bonded to an ancillary Schiff base ligand, into molecules with 12 or 11 peripheral alkyl chains has been successfully achieved. These new complexes, 1 and 2, respectively, are columnar liquid crystals between room temperature and about 50 degrees C. Both cyclometallated and ancillary ligands have been polyalkylated through either aryl ester (electron-withdrawing group) or aryl ether (electron-releasing group) linkages, in order to tune the HOMO/LUMO energy levels. The photoconductive properties of 1 and 2 have been studied as a function of their absorption properties before and after annealing, from the UV/Vis to NIR region. Compared with the reference compounds, tris-alkynyl benzene discotics, these new materials gave similar performances (sigma/I approximately 8x10(-13) S cm W(-1) with E = 10 V microm(-1) at lambda = 370 nm). Moreover, complex 2 shows a normalized photoconductivity sigma/I = 8.5x10(-13) S cm W(-1) at lambda = 760 nm. Organic photoconductors in such a high wavelength spectral range are not common and are usually assembled by mixing dyes with organic semiconductors.

A comparative photophysical, electrochemical and computational study of a series of Nile Red cyclopalladated and newly synthesised cycloplatinated complexes is reported. All complexes are luminescent at room temperature and the emission properties are governed by the nature of the cyclometallated dye. However, the presence of platinum(II) as metal centre decreases severely the emission quantum yield, while the electronegativity of the ancillary hexafluoroacetylacetonato ligand enhanced the emission properties of the Nile Red complexes.

A photophysical, electrochemical and computational study has been performed on a homologous series of cyclometallated Pd(II) (1a-f) and Pt(II) (2a-f) complexes of general formula [(C,N)M(O,O)]; (H(C,N) = azobenzene, 2-phenylpyridine, benzo[h]quinoline; M = Pd, Pt; H(O,O) = acetylacetone, hexafluoroacetylacetone). Experimental and computational data have shown the strong influence exerted by electronegativity of the ancillary ligand on the frontier orbitals of the complexes, such an effect being enhanced for the Pt(II) species.

Nanocrystals (50-250 nm) of a Palladium complex within a polyisobutylmethacrylate matrix were prepared by a phase separation method. In these dispersions, a light-induced birefringence with Deltan approximately 10(-3) was induced, without the application of an electric field. This effect was related to the photoconducting properties of the dispersion. Evidence for charge photogeneration without any applied field was obtained. The photorefractive behaviour of the material confirmed that the nanocrystals reorientation is a consequence of photoconducting properties. A light-generated electric field approximaely E 3 V/microm was estimated. These results illustrate the potential of materials with a nano-crystalline dispersion morphology as light-responsive media.

The coordination of the N,N ligands 2,2-bipyridine (bipy) and 1,10-phenanthroline (phen) to Ga(III) has been investigated via the formation of new ionic hexacoordinated complexes of general formula [Q'(2)Ga(N,N)][X], where HQ' stands for 2-methyl-8-hydroxyquinoline and the counter anion X(-) is nitrate (NO(3)(-)) or hexafluorophosphate (PF(6)(-)). All synthesized complexes were characterized by single-crystal X-ray diffraction analysis. The geometry of the Ga(III) cations is octahedral and a single geometric isomer (all N, N trans conformation) has been obtained in all cases. The role of both the N,N ligand and the counter anion has been investigated in the formation of the crystal supramolecular motifs occurring in the 3D-crystal networks of these new class of ionic Ga(III) derivatives. A full investigation of the photophysical properties of the new synthesized ionic species is reported and discussed in relation to their crystalline packing and the degree of crystallinity of thin solid films as well as the nature of the N,N ligand and the counter anion.

The scope of the present work is to highlight the effects stemming from different C60/exTTF linkages (exTTF = 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene)-either via an anthracene unit or a dithiole ring. Particular emphasis is placed on photoinduced electron-transfer features. Therefore, we devised a new series of C60-exTTF ensembles, synthesized via 1,3-dipolar cycloaddition and Diels-Alder cycloaddition reactions, in which exTTF units are separated from C60 by two single bonds (3a-c, 4), one vinylene unit (5a), or two vinylene units (5b). The cyclic voltammetry reveals an amphoteric redox behavior with remarkably strong electron-donor ability of the trimethyl-substituted exTTF moiety in 4 and 5a,b. Steady-state and time-resolved photolytic techniques show that the fullerene singlet excited state in (3a-c, 4, and 5a,b) is subject to a rapid electron-transfer quenching. The resulting charge-separated states, that is C60*(-)-exTTF*+, were identified by transient absorption spectroscopy. We determined radical pair lifetimes of the order of 200 ns in benzonitrile. This suggests (i) that the positive charge of the exTTF*+ is delocalized over the entire donor rather than localized on one of the 1,3-dithiole rings and (ii) that linking exTTF via the anthracene or 1,3-dithiole ring has no appreciable influence. Increasing the donor-acceptor separation via implementing one or two vinylene units as spacers led to improved radical pair lifetimes (5a: tau = 725 ns; 5b: tau = 1465 ns).

The synthesis of novel electrochemically amphoteric TTFAQ-sigma-A compounds (TTFAQ = 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene, sigma = saturated spacer, A = polynitrofluorene acceptor) is reported. Their solution redox behavior is characterized by three single-electron reduction and one two-electron oxidation waves. Electrochemical quasireversibility of the TTFAQ(2+) state and a low E(ox) - E(red) gap ( approximately 0.25 V) for 3-(9-dicyanomethylene-4,5,7-trinitrofluorene-2-sulfonyl)-propionic acid 2-[10-(4,5-dimethyl-[1,3]dithiol-2-ylidene)-9,10-dihydroanthracen-9-ylidene]-5-methyl-[1,3]dithiol-4-ylmethyl ester (10) has enabled the electrochemical generation of the hitherto unknown transient D(2+)-sigma-A(.-) state as observed in cyclic voltammetry and time-resolved spectroelectrochemistry. The ground state of compound 10 was shown to be ionic in the solid but is essentially neutral in solution (according to electron paramagnetic resonance). The X-ray structure of an intermolecular 1:2 complex between 2-[2,7-bis(2-hydroxyethoxy)-9,10-bis(4,5-dimethyl-[1,3]dithiol-2-ylidene)-9,10-dihydroanthracene and 2,5,7-trinitro-4-bromo-9-dicyanomethylenefluorene, 14.(17)(2), reveals, for the first time, full electron transfer in a fluorene charge-transfer complex.

We report the synthesis of a new series of cyclophanes 11a-d by ester-forming macrocyclization reactions of diol 9 with the dicarbonyl chloride derivatives of benzene, thiophene, ferrocene, and diphenyl ether, 10a-d, respectively. Compounds 11a-d display a two-electron, quasireversible oxidation wave in the cyclic voltammogram to yield the dication species at Eoxpa = 0.70-0.72 V (for 11a-c) and 0.47 V (for 11d) (vs Ag/AgCl in acetonitrile). The raised oxidation potentials for 11a-c reflect the reduced stability of the twisted dication structure within the steric constraints of the smaller cyclophanes. Consistent with this, the value of delta E (defined as Eoxpa - Eoxpc) decreases (i.e., reversibility of the oxidation process increases) in the sequence 11d > 11c > 11a > 11b as the bridging chain becomes shorter. X-ray crystal structures are reported for compounds 11a-d and the dication salt 11d2+(I3-)2.(CH2Cl2)2.25. For 11a-d the typical saddle-shaped conformation of the 9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene moiety is observed, with the strain imposed by the cyclophane ring being accommodated in the structure of the bridging unit. In the dication 11d2+ both dithiolium rings are planar and the anthracene unit is essentially aromatic, with the conformation of the bridge basically the same as in neutral 11d.