Hydride Migration from a Triangular Face to a Tetrahedral Cavity in Tetranuclear Iron Carbonyl Clusters upon Coordination of [AuPPh3]+ Fragments

Metal hydrides are of fundamental importance in chemistry, both as solid‐state materials and molecular compounds. The first low‐valent molecular metal cluster containing an interstitial four‐coordinate hydride in a tetrahedral site is decribed, which undergoes hydride migration from the surface to the tetrahedral cavity of the cluster upon coordination of a [AuPPh₃]⁺ fragment. The [HFe₄(CO)₁₂(AuPPh₃)₂]^? mono‐anion, which contains a surface μ₃‐H, was obtained from the reaction of [HFe₄(CO)₁₂]^3? with two equivalents of [Au(PPh₃)Cl]. This is, in turn, transformed into the neutral [HFe₄(CO)₁₂(AuPPh₃)₃] upon addition of a third [AuPPh₃]⁺ fragment, with concomitant migration of the unique hydride from the surface of the cluster to its tetrahedral cavity. All of these species have been fully characterized in solution by means of IR and multinuclear NMR spectroscopy, and in the solid state by single‐crystal X‐ray diffractometry.     

Cannabis Bioactive Compound-Based Formulations: New Perspectives for the Management of Orofacial Pain

The management of orofacial pain to alleviate the quality of life of affected patients is becoming increasingly challenging for scientific research and healthcare professionals. From this perspective, in addition to conventional therapies, new alternatives are being sought, increasingly looking at the use of both natural and synthetic products. Cannabis sativa L. represents an interesting source of bioactive compounds, including non-psychoactive cannabinoids, flavonoids, and terpenes, many of which are effective in improving pain intensity. Here, we aim to analyze the possible mechanisms of action of the bioactive natural and synthetic hemp-derived compounds responsible for the modulatory effects on pain-related pathways. The ability of these compounds to act on multiple mechanisms through a synergistic effect, reducing both the release of inflammatory mediators and regulating the response of the endocannabinoid system, makes them interesting agents for alternative formulations to be used in orofacial pain.     

A facile synthesis of hydrophilic poly(ε-caprolactone)-based poly(ether-ester-amide)s

Segmented poly(ether-ester-amide)s, (PEEA)s, of controlled hydrophilicity degree, based on poly(ε-caprolactone) (PCL), were synthesized according to a facile two-step procedure using α,ω-dihydroxy oligomeric PCL, 4,7,10-trioxa-1,13-tridecanediamine and macromers prepared from poly(ethylene glycol)s and adipoyl chloride. The PEEAs showed M _n values in the range 5–11.5 kDa. A PCL-type crystallinity was found by WAXS. DSC indicated T_m values (49–51 °C) close to that of PCL macromer. Single glass transitions were observed both by DSC and DMTA techniques and the T_g values (−58–−50 °C by DSC) were slightly higher than that of PCL. The water uptake was in the range 4.8–26.0 wt.-% depending on the length of the poly(ethylene glycol) segment.

Monomers used to prepare the PEEAs.     

Synthesis and Biological Evaluation of New Bis-Indolinone Derivatives Endowed with Cytotoxic Activity

A series of new Knoevenagel adducts, bearing two indolinone systems, has been synthesized and evaluated on 60 human cancer cell lines according to protocols available at the National Cancer Institute (Bethesda, MD, USA). Some derivatives proved to be potent antiproliferative agents, showing GI₅₀ values in the submicromolar range. Compound 5b emerged as the most active and was further studied in Jurkat cells in order to determine the effects on cell-cycle phases and the kind of cell death induced. Finally, oxidative stress and DNA damage induced by compound 5b were also analyzed.     

Characterization of the Trans-Epithelial Transport of Green Tea (C. sinensis) Catechin Extracts with In Vitro Inhibitory Effect against the SARS-CoV-2 Papain-like Protease Activity

This work describes an untargeted analytical approach for the screening, identification, and characterization of the trans-epithelial transport of green tea (Camellia sinensis) catechin extracts with in vitro inhibitory effect against the SARS-CoV-2 papain-like protease (PLpro) activity. After specific catechin extraction, a chromatographic separation obtained six fractions were carried out. The fractions were assessed in vitro against the PLpro target. Fraction 5 showed the highest inhibitory activity against the SARS-CoV-2 PLpro (IC₅₀ of 0.125 μg mL⁻¹). The untargeted characterization revealed that (−)-epicatechin-3-gallate (ECG) was the most abundant compound in the fraction and the primary molecule absorbed by differentiated Caco-2 cells. Results indicated that fraction 5 was approximately 10 times more active than ECG (IC₅₀ value equal to 11.62 ± 0.47 μg mL⁻¹) to inhibit the PLpro target. Overall, our findings highlight the synergistic effects of the various components of the crude extract compared to isolated ECG.     

Harpagophytum procumbens extract potentiates morphine antinociception in neuropathic rats

The association of opioids and non-steroidal anti-inflammatory drugs, to enhance pain relief and reduce the development of side effects, has been demonstrated. Given many reports concerning the antinociceptive and anti-inflammatory effects of Harpagophytum procumbens extracts, the aim of our study was to investigate the advantage of a co-administration of a subanalgesic dose of morphine preceded by a low dose of H. procumbens to verify this therapeutically useful association in a neuropathic pain model. Time course, registered with the association of the natural extract, at a dose that does not induce an antinociceptive effect, followed by a subanalgesic dose of morphine showed a well-defined antiallodynic and antihyperalgesic effect, suggesting a synergism as a result of the two-drug association. H. procumbens cooperates synergistically with morphine in resolving hyperalgesia and allodynia, two typical symptoms of neuropathic pain. The results support the strategy of using an adjuvant drug to improve opioid analgesic efficacy.     

Conductive sub-micrometric wires of platinum-carbonyl clusters fabricated by soft-lithography

Conductive wires of sub-micrometer width made from platinum-carbonyl clusters have been fabricated by solution-infilling of microchannels as in microinject molding in capillaries (MIMIC). The process is driven by the liquid surface tension within the micrometric channels followed by the precipitation of the solute. Orientation of supramolecular crystalline domains is imparted by the solution confinement combined with unidirectional flow. The wires exhibit ohmic conductivity with a value of 0.2 S/cm that increases, after thermal decomposition of the platinum-carbonyl cluster precursor to Pt, to 35 S/cm.     

Putative palytoxin and its new analogue,ovatoxin-a,in <Emphasis Type="Italic">Ostreopsis ovata</Emphasis> collected along the ligurian coasts during the 2006 toxic outbreak

In this article we report on the liquid chromatography tandem mass spectrometry (LC-MS) investigation of plankton samples collected in the summer of 2006 along the Ligurian coasts, coinciding with a massive bloom of the tropical microalga Ostreopsis ovata. LC-MS analyses indicated the occurrence of putative palytoxin along with a much more abundant palytoxin-like compound never reported so far, which we named ovatoxin-a. On the basis of molecular formula, fragmentation pattern, and chromatographic behavior, the structure of ovatoxin-a appeared to be strictly related to that of palytoxin. We report also on the analysis of cultured O. ovata, which was necessary to unequivocally demonstrate that putative palytoxin and ovatoxin-a contained in field samples were actually produced by O. ovata itself.     

Ultraviolet-based bonding for perfluoropolyether low aspect-ratio microchannels and hybrid devices

Producing solvent-resistant microfluidic devices is a challenge for analytical chemistry and biochemistry. We demonstrate a simple and low-cost fabrication approach for the realization of solvent-resistant microchannels based on perfluoropolyether elastomers, exhibiting very low aspect ratios (0.01). The strength of the microchannels sealing is evaluated through the maximum internal pressure (1.52 MPa) prior to device failure, due to delamination at the bonded interface. This approach allows the elastic properties of silicone elastomers, suitable for high quality external connections, to be combined with the non-swelling character of perfluoropolyethers.     

Bimetallic Fe–Cu Carbido Carbonyl Clusters Obtained from the Reactions of [Fe<Subscript>4</Subscript>C(CO)<Subscript>12</Subscript>{Cu(MeCN)}<Subscript>2</Subscript>] with N-Donor Ligands

The reaction of [Fe₄C(CO)₁₂{Cu(MeCN)}₂] (1) with 3 equivalents of L–L (phen or Me₂phen) affords [Cu(L–L)₂][Fe₄C(CO)₁₂{Cu(L–L)}] (L–L = phen, 2; Me₂phen, 3) in good yields. These are protonated by strong acids resulting in [HFe₄C(CO)₁₂{Cu(L–L)}] (L–L = phen, 4; Me₂phen, 5). The reaction may be reversed with bases, resulting in the quaternary ammonium salts [NR₄][Fe₄C(CO)₁₂{Cu(phen)}] (6). 4 and 5 react with a slight excess of L–L resulting in the elimination of copper in the form of [Cu(L–L)₂]⁺ and formation of the previously reported [HFe₄C(CO)₁₂]^? homometallic cluster. Conversely, the reaction of 1 with a monodentate N-ligand such as quinoline, even if used in large excess, results in the substitution product [Fe₄C(CO)₁₂{Cu(quinoline)}₂] (8), which is then transformed into [Cu(Me₂phen)₂] [Fe₄C(CO)₁₂{Cu(quinoline)}] (9) after reaction with Me₂phen. By using the anionic cluster [Fe₅C(CO)₁₄{Cu(MeCN)}]^? instead of the neutral 1, only substitution has been observed by using both phen and quinoline, resulting in [Fe₅C(CO)₁₄{Cu(phen)}]^? (10) and [Fe₅C(CO)₁₄{Cu(quinoline)}]^? (11), respectively. Finally, the reaction of 1 with [Ru(tpy)(bpy)(N₄C-C₆H₄-CN)]Cl affords crystals of [Fe₄C(CO)₁₂Cu₂Cl{Ru(tpy)(bpy)(N₄C-C₆H₄-CN)}] (12). All compounds 2-12 have been characterized by a combination of spectroscopic (IR, NMR) and crystallographic methods. All these clusters may be viewed as composed by a butterfly [Fe₄C(CO)₁₂]^2? core bonded to Cu(I) fragments and/or H⁺ ions.