Thionation of the monoacetal of pentacyclo[5.4.0.0.0.0]undecane-8,11-dione

As part of a programme to synthesize thione derivatives with pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane moieties it was decided to sulfurize the monoacetal 6 of pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane-8,11-dione 2. Unexpectedly the diol 9 was isolated as the product.     

Persistence of oxidation state III of gold in thione coordination

Ligands N,N'-tetramethylthiourea and 2-mercapto-1-methyl-imidazole form stable Au(III) complexes [AuCl₃(N,N'-tetramethylthiourea)] (1) and [AuCl₃(2-mercapto-1-methyl-imidazole)] (2) instead of reducing the Au(III) metal center into Au(I), which would be typical for the attachment of sulfur donors. Compounds 1 and 2 were characterized by spectroscopic methods and by X-ray crystallography. The spectroscopic details were explained by simulation of the UV-Vis spectra via the TD-DFT method. Additionally, computational DFT studies were performed in order to find the reason for the unusual oxidation state in the crystalline materials. The preference for Au(III) can be explained via various weak intra- and intermolecular interactions present in the solid state structures. The nature of the interactions was further investigated by topological charge density analysis via the QTAIM method.     

Quantification of L‐ergothioneine in whole blood by hydrophilic interaction ultra‐performance liquid chromatography and UV‐detection

A new hydrophilic interaction ultra‐performance LC method was established for the whole blood measurement of L‐ergothioneine. Chromatographic separation was achieved in a fairly short time, less than 4 min, on a 100 × 2.1 mm Acquity UPLC BEH HILIC 1.7 μm column with a mobile phase consisting of a mixture of 100 mmol/L ammonium acetate/ACN/water (5:85:10, v/v/v) that flowed isocratically at 0.250 mL/min. The LOD and the limit of quantification were 3.85 and 11.67 μmol/L, respectively. The method exhibited linearity in a concentration range of 15.63–1000 μmol/L (R² > 0.999). Mean recovery was 96.34% whereas intraassay and interassay precision were 1.52 and 1.82% RSD, respectively. On the whole, the developed method is simple, fast, precise, accurate, and sensitive and may be useful for routine analyses.     

Spectroscopic,biological activity studies,and DFT calculations,of Pd(II) and Pt(II) complexes of 4-Methylene-3-phenyl-3,4-dihydroquinazoline-2(1H)-thione

Four palladium (II) and platinum(II) complexes with the formula [MCl₂(HPhqS)₂] and [M(PhqS)₂] (M^II = Pd and Pt), were synthesized by treating Na₂PdCl₄ or K₂PtCl₄ with 2 mol of 4-Methylene-3-phenyl-3,4-dihydroquinazoline-2(1H)-thione (HPhqS) with or without the present base. The geometry around the Pd(II) and Pt(II) ions was a square planner and the HPhqS ligand was bonded as monodentate through the sulfur atom in complexes (1) and (2), while as bidentate chelating ligand through the nitrogen and sulfur atoms in complexes (3) and (4) as revealed by the data collection from spectroscopic studies. The prepared compounds were fully characterized by different physicochemical and spectroscopic methods. Furthermore, the free HPhqS ligand and its complexes were evaluated in vitro in regard to their antimicrobial activity against five bacteria species (Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, staphylococcus epidermidis and staphylococcus aureus). Moreover, the cytotoxic activity of the compounds was examined against breast (MCF-7) and lung (A549) cancer cell lines, and the [PdCl₂(LH)₂] (1) and [PtCl₂(LH)₂] (2) appeared a highest inhibitory effect against MCF-7 cell lines with IC₅₀ = 4.291 ± 0.181 μM and 3.479 ± 0.162 μM, respectively, in comparison to the standard control and other complexes. The prepared ligand accompanied by the synthesized complexes were optimized using B3LYP method and 6–311++G(d,p) biases sets for the ligand and SDD basis set for the central metal. Different quantum parameters including electron affinity, ionization energy, dipole moment, hardness and vibrational frequencies were calculated for the ligand and its complexes. The total energy calculated for the two tautomeric structures of the ligand HPhqS showed a slightly higher value of the thione form over the thiol form. In addition, the trans-[PdCl₂(HPhqS)₂] complex possessed the highest dipole moment values while the cis-[PtCl₂(HPhqS)₂] showed non. In general, the obtained theoretical results showed a good match to the experimental findings.     

Crystal structures of copper(II) complexes of 2-formylpyridine substituted thiosemicarbazones; the first example of a coordinated thiosemicarbazone with a thiol function

The crystal structures of two 5-coordinate copper(II) complexes containing neutral, tridentate 2-formylpyridine N(4)-substituted thiosemicarbazones have been determined. 2-Formylpyridine N(4)-cyclohexylthiosemicarbazone, HFo4CHex coordinates via the pyridine nitrogen, imine nitrogen and thione sulfur with two chloro ligands to produce [Cu(HFo4CHex)Cl₂]. Similarly, 2-formylpyridine 3-(4-methylpiperazine)thiosemicarbazone, HFoppz4M, produces [Cu(HFoppz4M)Cl₂] with one major difference; rather than the expected thione form of the thiosemicarbazone moiety, it coordinates as the thiol isomer. Both complexes are close to a square pyramid structure with axial and equatorial chloro ligands and the thiosemicarbazone moieties of both ligands nearly planar. Also included is the crystal structure of N-cyclohexylthiosemicarbazide, CHextsc.     

Crystal Study of Salicylaldehyde N(4)-Phenylthiosemicarbazone

Abstract The crystal structure of salicylaldehyde N(4)-phenyl thiosemicarbazone is described. The compound crystallizes in the triclinic crystal system, space group P Z = 6, V = 2002.1(5) ?³ with unit cell parameters a = 10.6733(15) ?, b = 13.8856(19) ?, c = 14.052(2) ?, α = 81.851(2)°, β = 77.061(2)° and γ = 83.482(2)°. There are three independent molecules in the asymmetric unit. The crystal structure reveals that the compound exists in the thione form and S1 and N3 are at E configuration to each other with respect to N2–C7 bond. Similarly, S2 and N6 are trans to each other with respect to N5–C21 bond in the second molecule of the asymmetric unit and S3 and N9 are trans to each other with respect to N8–C35 bond in the third molecule of the asymmetric unit. The packing of the molecules in the crystal lattice is stabilized by intermolecular hydrogen bonds. Index Abstract The compound salicylaldehyde N(4)-phenyl thiosemicarbazone crystallizes in the triclinic crystal system, space group P Z = 6, V=2002.1(5) ?³ with unit cell parameters a = 10.6733(15) ?, b = 13.8856(19) ?, c = 14.052(2) ?, α = 81.851(2)°, β = 77.061(2)° and γ = 83.482(2)°. The structure of the compound salicylaldehyde N(4)-phenylthiosemicarbazone