Site selectivity in carbon monoxide insertion into a PtC σ-bond of the binuclear complex [(CH3)ClPt(μ-Cl) (μ-Ph2PPy) Pt(CH3)(DMSO)]DMSO. Structural characterization of the derivatives [(CH3CO)ClPt(μ-Cl)(μ-Ph2 PPy)Pt(CH3)(DMSO)] and [(CH3)ClPt(μ-Ph2PPy)2Pt(COCH3)]+

Title full: Site selectivity in carbon monoxide insertion into a PtC \u3c3-bond of the binuclear complex [(CH3)ClPt(\u3bc-Cl) (\u3bc-Ph2PPy) Pt(CH3)(DMSO)]DMSO. Structural characterization of the derivatives [(CH3CO)ClPt(\u3bc-Cl)(\u3bc-Ph2 PPy)Pt(CH3)(DMSO)] and [(CH3)ClPt(\u3bc-Ph2PPy)2Pt(COCH 3)]+. Carbon monoxide reacts with [(CH3)ClPt(\u3bc-Cl)(\u3bc-Ph2PPy)Pt(CH3) (DMSO)]DMSO, 1, to give [(CH3CO)ClPt(\u3bc-Cl)(\u3bc-Ph2 PPy)Pt(CH3)(DMSO)] 2. The insertion of CO into a platinum-carbon \u3c3-bond of 1 shows a site selectivity, occurring at the Pt CH3 bond involving the metal atom connected to the P atom of the 2-(diphenylphosphino)pyridine (Ph2PPy). Under a carbon monoxide atmosphere for about 30 h, 1 forms the ionic compound [(CH3)ClPt(\u3bc-Ph2PPy)2Pt(COCH3 )][Pt(CO)(COCH3)Cl2], 3. Complex 2 changes slowly into 3. It was not possible to obtain crystals of 2 or 3 suitable for X-ray investigations. A crystal species was isolated containing both 2 and 3 in a 1 : 1 ratio. The crystals are triclinic, space group P1 (no. 2), with a = 10.326(4) \uc5, b = 16.648(4) \uc5, c = 22.203(4) \uc5, \u3b1 = 90.95(2)\ub0, \u3b2 = 96.50(2)\ub0, \u3b3 = 95.44(2)\ub0. The refinements, based on 3255 significant reflections, gave a final R value of 0.0621. The molecular structure of the neutral species 2 is similar to that of the parent compound 1, with a CH3CO group in place of a methyl. The structure of the anion of 3 was incompletely characterized because of disorder. The [(CH3)ClPt(\u3bc-Ph2PPy)2Pt(COCH3 )]+ cation has a direct PtPt bond of 2.728(3) \uc5 bridged by the two Ph2PPy ligands in a head-to-tail fashion. One of the Pt atoms completes its coordination with an acetyl group and is four-coordinate, whereas the second containing both a chlorine atom and a methyl group, is five-coordinate. Semi-empirical MO calculations for the cation have been performed, and show the dative nature of the PtII \u2192 PtII bond

Forensic pathological study of methadone-related deaths in the Genoa (Italy) district: A six-year study

Methadone is a synthetic opioid, a pure agonist of the μ receptor. It is used for opioid maintenance therapy in heroin addiction. In recent years, Italian studies of incidence and prevalence have indicated an increase in the illegal sales of methadone and, consequently, an increase in deaths due to acute methadone intoxication as well. The present review is a prospective-observational study regarding epidemiological and toxicological analyses of methadone-related deaths recorded in the district of Genoa (Italy) from 2013 to 2018. The study includes a list of twenty-six people that have died from methadone toxicity: twenty-two males and four females. The concentration of methadone in the blood samples ranged from 181 to 4058.53 ng/mL, with an average of 964.29 ng/mL. Six subjects tested positive for methadone alone; twenty cases, however, presented drugs or substances in different concentrations in the blood samples. Illegal sales and consumption of methadone have a negative impact on the self-administration therapy of opioid addiction, inducing patients to increase their dosage or sell methadone in order to purchase illegal drugs. As shown in our study, this behaviour is associated with an increase in methadone-related deaths. Accordingly, careful monitoring of dosage administrated to patients is required in order to render the system safer

Origin of enantioselectivity in palladium-catalyzed asymmetric allylic alkylation reactions using chiral N,N-ligands with different rigidity and flexibility

The chiral bidentate-N,N ligands, (Sa)-1, (Sa)-2, (S,S)-3 and (S,S)-4, were synthesized. They were shown to contain rigid 2-pyridinyl or 8-quinolinyl building blocks and the C2-symmetric chiral frameworks trans-2,5-dimethylpyrrolidinyl or (S)-(+)-2,2′-(2- azapropane-1,3-diyl)-1,1′-binaphthalene. In the (Sa)-2, and (S,S)-4 ligands pair, the 8-quinolinyl skeleton is directly bonded to the C 2-symmetric chiral frameworks (S)-(+)-2,2′-(2-azapropane-1,3- diyl)-1,1′-binaphthalene or trans-2,5-dimethylpyrrolidinyl. This feature induces rigidity in this pair of ligands upon the N,N-framework. However, this does not occur for the (Sa)-1 and (S,S)-3 ligands, in which the presence of the -CH2- spacer between the frameworks bearing the nitrogen atom donors gives greater flexibility to the ligand. A further difference between the pairs of ligands is significant from the electronic properties of the chiral framework N-donor atom. The coordinating properties and the specific steric structural features of the (Sa)-1, (S a)-2, (S,S)-3, and (S,S)-4 ligands are explained by their reactions with the [Pd(PhCN)2Cl2] and [Pd(η3- PhCHCHCHPh)(-Cl)]2 substrates, in which the reported ligands form chelate complexes, with the exception of (Sa)-2, which failed to react with [Pd(η3-PhCHCHCHPh)(-Cl)]2. The ligands were used in the palladium-allyl catalyzed substitution reaction of 1,3-diphenylallyl acetate with dimethylmalonate, with the best result being obtained using the (Sa)-1 ligand, giving the substitution product 2-(1,3-diphenylallyl)dimethylmalonate with an enantiomeric excess of 82% in the S form and a yield of 96%. The work demonstrates that in the presence of a steric ligand control, the electronic properties of the ligand donor atoms play a role though not significant in determining the enantioselectivity of palladium(ii) catalyzed allylic substitution reactions. The results of the catalytic reaction do not provide a convincing explanation considering the coordinated chiral ligand features, as rigidity or flexibility and electronic properties of the N-donor atoms. A rationalization of the results is proposed on the basis of NMR studies and DFT calculation on the cationic complexes [Pd(η3-PhCHCHCHPh)(N-N*)]CF3SO3, (N-N* = (Sa)-1, 9; (S,S)-3, 10; (S,S)-4, 11). © The Royal Society of Chemistry 2007