Exploring a possibility of β-myrcene (MY) incorporation in propene copolymerization has been studied in the presence of phenoxide-modified half-titanocene, Cp’TiCl2(O-2,6-iPr2-4-C6H3) (Cp’ = Cp*, Me3SiC5H4), and ketimide-modified half-titanicene, Cp’TiCl2(N=CtBu2) (Cp’ = Cp*, Cp), catalysts. The permethylated Cp* catalysts exhibited good catalytic activities in the copolymerizations but afforded the copolymers up to 3 mol% MY incorporation; the other catalysts showed the negligible activities. The resulting copolymers were amorphous and exhibited glass transition temperatures (Tg) that de-creased with increasing the comonomer (MY) content, reaching values as low as −17 °C.

Understanding the mechanism of action of antimicrobial agents is critical for guiding the development of new drugs to overcome antimicrobial resistance. We present a label-free NMR-based approach to characterize the mechanism of action of antibacterial compounds and materials by the analysis of metabolite secretion kinetics. The method (KINEXO, KINetics of EXOmetabolites) is set up using Escherichia coli and Staphylococcus aureus as representative Gram-negative and Gram-positive model organisms. By monitoring the real-time production of key secreted metabolites (acetate, formate, lactate, ethanol, pyruvate, succinate) in response to antimicrobial treatment and analyzing the secretion kinetics, we can classify the agents' mechanisms of action. We validate KINEXO using agents with well-characterized mechanism of action (kanamycin, ampicillin, irgasan, caprylic acid, graphene-like nanoparticles, and a functionalized silicon material), and we further apply it to silver nanoparticles, whose mechanism of action remains under debate. Agents that perturb the cell envelope reduce secretion rates while maintaining end-point metabolite concentrations with only moderate lag phase extension. In contrast, agents that act on intracellular pathways drastically prolong lag phases and reduce both secretion rates and end-point concentrations. When plotted in 3D parameter space (exometabolite secretion lag time, secretion rate, end-point concentration), antibacterial agents cluster according to their mode of action, offering a mechanistically informative phenotypic readout. This platform provides a generalizable and robust analytical framework for rapid antimicrobial profiling and mechanism-based screening of novel bioactive agents.

The development of polyolefin from bio-renewables has been considered an important subject in terms of circular economy. In this study, exploring the possibility of beta-myrcene (MY) incorporation in propene copolymerization has been studied in the presence of various catalysts: phenoxide-modified half-titanocene, Cp'TiCl2(O-2,6-iPr2-4-C6H3) [Cp' = Cp* (C5Me5), Me3SiC5H4], and ketimide-modified half-titanicene, Cp'TiCl2(N=CtBu2) (Cp' = Cp*, Cp). Among the complexes tested, the permethylated Cp* catalysts, Cp*TiCl2(O-2,6-iPr2-4-C6H3) and Cp*TiCl2(N=CtBu2), exhibited moderate catalytic activities in the copolymerizations, affording the copolymers up to 3 mol% MY incorporation. The other catalysts showed negligible activity in the attempted copolymerizations. The resulting copolymers were amorphous and possessed sole glass transition temperatures (Tg), suggesting uniform compositions; the Tg values decreased with increasing comonomer (MY) content, reaching values as low as -17 degrees C. The results introduce valuable insights into the structure-property relationships of myrcene-based copolymers and pave the way for the future designs of tailored molecular catalysts for the synthesis of biobased elastomers.

The ketimide half-titanocene catalysts 1–3 yielded high molar mass propene-norbornene copolymers (P- co -N) with efficient N incorporation and tensile properties ranging from ductile and tough materials to stiff and fragile ones as N content increases.

Several nickel dichloride phosphine complexes have been synthesized, their crystalline structure determined, and their behavior, in combination with methylaluminoxane, in the polymerization of butadiene has been examined. High-cis polybutadienes were consistently obtained, regardless of the nature of the phosphine coordinated to the metal and the methylaluminoxane/Ni molar ratio used, contrary to what was previously observed in the polymerization of butadiene with analogous cobalt phosphine complexes, in which catalytic selectivity was found to be strongly influenced by these two factors. An interpretation for such different behavior is provided.

One possible way to store the excess CO2 present in atmosphere is to use it as a reagent for the synthesis of commodities. In particular, CO2 and epoxides can be copolymerized to produce a large variety of polycarbonates which appear very promising in various application fields. Further, the addition of an appropriate transfer agent in the reaction mixture promotes the formation of telechelic polycarbonates which can be used where specific functional polymers are necessary. In this work, (hydroxyethyl) methacrylate and 2-hydroxyethyl-2-bromoisobutyrate species are exploited as transfer agents in the copolymerization of CO2 and cyclohexene oxide, in the presence of a macrocyclic phenolate dimagnesium catalyst. The effect of the transfer agent concentration on the polycarbonate characteristics is evaluated. Finally, the obtained telechelic polycarbonates are used as macromonomers and macroinitiators in the synthesis of statistical and block copolymers.

Trialkylsilyl-substituted half sandwich titanium complexes containing ketimide ligands, (RC5H4)TiCl2((NCBu2)-Bu-t) (R = SiMe3, SiEt3), especially the SiEt3 analogue, exhibited superior catalytic activities with efficient norbornene (NBE) incorporation (25 700-91 400 kg polymer per mol Ti h(-1); NBE 36.2-72.7 mol%) in the ethylene/NBE copolymerisation at 50 degrees C to afford high molecular weight copolymers with high NBE contents (NBE > 60 mol%). These complexes also displayed superior capability for efficient synthesis of ethylene copolymers with tetracyclododecene (TCD) at 50 degrees C, and synthesis of high molar mass copolymers with high glass transition temperatures (T-g = 255 degrees C, TCD 52.3 mol%) has been achieved. Efficient synthesis of high molar mass cyclic olefin copolymers (COCs) possessing high T-g values has been demonstrated by using these catalysts.

Propylene polymerizations with different ketimide-modified half-titanocene catalysts, Cp’TiCl2(N=CtBu2) [Cp’ = C5H5 (1), C5Me5 (2), Me3SiC5H4 (3)], with MAO as a cocatalyst, were investigated. The obtained polymers were studied in detail by determining their microstructure, molar masses, thermal, and mechanical properties. The Cp*-ketimide, (C5Me5)TiCl2(N=CtBu2) (2), exhibited higher catalytic activities than Cp’TiCl2(N=CtBu2) (1,3), yielding higher molar mass polymers, Mw up to 1400 Kg/mol. All the synthesized polypropylenes (PP) are atactic and highly regioregular, with predominant rrrr pentads, especially PP prepared with catalyst 1. Differential scanning calorimetry (DSC) established that the polymers are fully amorphous aPP, and no melting endotherm events are detected. Glass transition temperatures were detected between −2 and 2 °C. These polypropylenes have been established to be high-performance thermoplastic elastomers endowed with remarkably high ductility, and a tensile strain at break higher than 2000%.

Some novel manganese and nickel complexes were synthesized by reacting manganese(II) dichloride and nickel(II) dichloride with pyridyl-imine ligands differing in the nature of the substituents at the imino nitrogen atom. All the complexes were characterized by analytical and infrared data: for some of them single crystals were obtained, and their molecular structure was determined by X-ray diffraction. The complexes were used in association with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene obtaining active and selective catalysts giving predominantly 1,2 polybutadiene in case of manganese catalysts and exclusively cis-1,4 polybutadiene in case of nickel catalysts.

Three poly(cyclohexene carbonates) with molecular weights ranging from 4.9 to 9.4 kg/mol were synthesized from cyclohexene oxide and CO2 using macrocyclic phenolate dimetallic catalysts and purified by conventional purification procedure. A decrease in thermal stability of approximately 100 degrees C was observed in comparison to poly(cyclohexene carbonates) with similar molecular weights synthesized using salen metal catalysts. This decrease derives from the presence of traces of dimetallic catalyst which is able to promote the depolymerisation of poly(cyclohexene carbonate) to CO2 and cyclohexene oxide in contrast to the usual backbiting mechanism that leads to cyclic carbonate. The onset of the degradation can be precisely tuned by changing the amount of residual dimetallic catalyst or including species with functional groups that can reduce the availability of the catalytic centers. Therefore, the possibility of controlling the thermal stability of poly(cyclohexene carbonates) by varying the concentration of the catalyst and the surrounding chemical environment paves the way for the use of these polymers as components in self-sacrificial materials of interest for advanced applications.

A mechanochemical process is proposed as an innovative approach to the synthesis of polypropylene-based macromolecular stabilizers with outstanding thermal behavior. Properly designed butylated hydroxytoluene antioxidants (BHT) and hindered amine light stabilizers (HALS) are covalently linked to polypropylene grafted with maleic anhydride (PP-g-MA) using a ball-mill apparatus under mild and solvent-free conditions. The study reports a quantitative evaluation of the degree of functionalization based on ATR-FTIR quantification technique and the solid-state NMR spectroscopy characterization of the ensuing materials. This strategy is a significant step towards safe and sustainable chemical synthesis in the field of macromolecular materials.

Bio-polyols (BPOs), characterized by a hydroxyl number up to around 90 mg KOH/g, narrow polydispersity index and relatively low molecular mass up to 2000 g/mol, were synthetized from partially and completely epoxidized soybean and linseed oils and caprylic acid or 3-phenyl butyric acid. These BPOs were used in the presence of toluene diisocyanate to produce polyurethane (PU) foams by using a quasi-prepolymer method involving a two-step reaction. A detailed structural investigation of the prepolymers from toluene diisocyanate and both BPOs and polypropylene glycol was conducted by SEC and solution NMR. The apparent density of the foams was in the range of 40–90 kg/m3, with higher values for foams from the aromatic acid. All the foams showed an open-cell structure with uniform and regular shape and uniform size. The specific Young’s moduli and compression deflection values suggest superior mechanical properties than the reference foams. The novel synthesized polyurethanes are excellent candidates to partially replace petroleum-based materials.

The alternating copolymerization of CO2 and CHO with salen-type chromium complexes salenCrX, where X is chloride (1) or azide (2) with different cocatalysts under the same experimental conditions, has been described. The cocatalysts include TPPCl, DMAP, UHFFA, PPNY and PPZY salts, where Y is chloride or azide. A detailed end-group analysis via MALDI-TOF was performed and the complex patterns of MALDI-TOF spectra of the co-polymers were rationalized for comparison with results obtained by 1H NMR spectroscopy, as well as by the catalytic behavior and copolymer characteristics. It appears that the entire structure of the cocatalyst, and not only the anion, should be considered in designing the structure of polycarbonates.

Branched phosphazenium salts are tested as alternative cocatalysts to traditional PPNX salts in the CO2/epoxide copolymerization with different catalysts. Higher molecular weights and comparable or superior conversions and selectivities are achieved.

Water-blown polyurethane (PU) foams were prepared by bio-polyols from epoxidized linseed oils and caprylic acid in combination with toluene diisocianate (TDI). A series of terpenes (menthol, geraniol, terpineol, and borneol), natural compounds with recognized antibacterial properties, were included in the starting formulations to confer bactericidal properties to the final material. Foams additivated with Irgasan®, a broad-spectrum antimicrobial molecule, were prepared as reference. The bactericidal activity of foams against planktonic and sessile E. coli (ATCC 11229) and S. aureus (ATCC 6538) was evaluated following a modified AATCC 100-2012 static method. Menthol-additivated foams showed broad-spectrum antibacterial activity, reducing Gram+ and Gram− viability by more than 60%. Foams prepared with borneol and terpineol showed selective antibacterial activity against E. coli and S. aureus, respectively. NMR analysis of foams leaking in water supported a bactericidal mechanism mediated by contact killing rather than molecule release. The results represent the proof of concept of the possibility to develop bio-based PU foams with intrinsic bactericidal properties through a simple and innovative synthetic approach.

Organosulfur polymers prepared via the inverse vulcanization of elemental sulfur with olefinic comonomers represent a new class of high-chalcogenide content organic/inorganic macromolecules. Extensive reporting on new synthetic advances and materials derived from the inverse vulcanization process have been explored in the past decade. However, detailed structural analysis of these sulfur copolymers have not been rigorously conducted, due to the poor solubility of many of these materials, coupled with the numerous side-reactions that result in complex microstructures from these synthetic methods. In the current report, we revisit analysis of the solution C-13 NMR spectral data for poly(S-r-Sty) and identify for the first time previously unidentified carbon peaks that offer new insights into a corrected repeating unit structure of this sulfur copolymer.

The catalytic activity of various zinc(II) complexes bearing a chelating nitrogen-donor ligand and different ancillary ligands (Cl, acetate, triflate) is investigated for the solvent-free coupling reaction of cyclohexene oxide and CO2. The effect of a co-catalyst is also studied. Whereas the investigated zinc(II) complexes with chloride or acetate as ancillary ligand are inactive, those with triflate are active, allowing the selective formation of polyether or cyclic carbonate controlled by the presence of a suitable amount of [PPN]Cl.

Stable ter-polysulfides from bio-based low cost dipentene and crosslinkers with a sulfur content greater than 50 wt% were synthesized by catalytic inverse vulcanization. Shape persistent polystyrene-polysulfide blends able to bind Fe 2+ were obtained.

Synthesis of unique poly(E-ter–N-ter–O)s using half-titanocene catalysts: 1-octene does not behave as a chain termination/transfer agent unlike ansa-metallocenes.

Bio-polyols from epoxidized soybean and linseed oils and caprylic acid or 3-phenyl butyric acid were prepared using an environmentally friendly, solvent-free method evaluating the presence of triethylamine as catalyst. Side reactions, leading to a cross-linking structure with high density, were reduced, introducing the catalyst and properly tuning the reaction conditions. A medium functionality value of around 3 along with a hydroxyl number up to around 90 mg KOH/g, narrow polydispersity index, and relatively low molecular mass up to 2400 g/mol were the experimental targets. From selected bio-polyols and an aliphatic partially bio-based isocyanate, a series of water blown polyurethane (PU) foams was produced, estimating the effect of the chemical nature of substituents in the polyol backbone on the PU properties. The apparent density of the foams was in the range of 79–113 kg/m3, with higher values for foams from the aromatic acid. Flexible polyurethane foams with open cell structure from bio-based polyols were obtained, with higher cavity size and lower pore sizes for foams from caprylic acid. The bio-based flexible PU foams showed comparable Young’s moduli (14–18 kPa) and compression deflection values (4.6–5.5 kPa) and exhibited an almost complete recovery of their initial size.