We report on the synthesis of optically pure cyclometalated iridium(III) complex-peptide hybrids as amphiphilic peptide conjugates (IPH-ACs) from Δ- and Λ-Ir(tpyCO2H)3 (tpy: 2-(4’-tolyl)pyridine) by optical resolution via diastereomeric intermediates conjugated with the chiral alcohol, (1R,2R)-2-aminocyclohexanol ((R,R)-11).  Spectroscopic spectra of the optically pure IPH-ACs that were prepared from Δ- and Λ-Ir(tpyCO2H)3 are reported.  It was found that both optically pure IPH-ACs induce paraptotic cell death in Jurkat cells and the EC50 values were evaluated by MTT assays.  We also performed TEM analyses of Jurkat cells treated with Λ-13 to observe morphological changes that occurred, and cytoplasmic vacuolization, a characteristic feature of paraptosis, was observed.  The intracellular uptake of IPH-ACs by the cells measured by ICP-MS (inductively coupled plasma-mass spectrometry) was higher for the Λ-forms and the EC50 values of the Λ-forms were slightly lower than those of the Δ-IPH-ACs.  The intrinsic cytotoxicity of the IPH-ACs, taking into account the fact that the intracellular uptake and the intrinsic cytotoxicity is almost equal for the Δ- and Λ-forms, suggests that the difference in cytotoxicity against Jurkat cells is due to the selectivity in the intracellular uptake of each stereoisomer.

Cobalt molybdenum nitrides can be obtained from the oxidic precursor by reaction with gaseous ammonia. Despite the large number of works regarding catalytical properties of these compounds, there are relatively few reports about the initial transformation from oxide to nitride. In this work, the influence of the precursor structure on the active phase formation and catalytic properties of cobalt molybdenum nitrides is examined. Oxidic precursors were obtained by precipitation at different pH values controlled by the addition of aqueous ammonia. The parameters of the precipitation process affected the composition and properties of the materials. The ammonolysis of NH4Co2OH(MoO4)2·H2O was investigated in situ with the use of X-ray powder diffraction and thermogravimetry. The ammonia synthesis activity of the obtained catalysts was compared to the reference iron catalyst. The formation of the Co3Mo intermetallic phase was suggested as the factor governing high activity.

This work presents the synthesis and characterization of mono (1) and di-nuclear (2) imidazolium salts stabilized by [AuPPh3]+ fragments. The presence of the gold moiety induces a significant decrease in the carbenic proton's acidic character (high pKa). This high stability is consistent with the pronounced instability of the conjugate bases obtained through deprotonation using strong bases. The formation of carbene species is accompanied by the identification of a 1,2-rearrangement process in which a preference for the C-bound species over the N-bound species is observed. Experimental techniques such as NMR, single-crystal X-ray diffraction analysis, mass spectrometry, and computational calculations are employed to investigate the reactivity exhibited by the imidazolium salts. Additionally, the electrochemical properties of the two imidazolium salts were also investigated. This study reveals that both species 1 and 2 display two cathodic peaks which are related to two electro-chemical irreversible reduction events. The results obtained from both experimental and theoretical studies of this system reveal a strong tendency of the [AuPPh3]+ fragment to stabilize imidazolium salts. Additionally, they demonstrate the preference of this fragment for C-bound species over N-bound ones, with the former proving to be highly unstable even under severe conditions of air and moisture exclusion.

Rare-earth-metal (Ln) alkyl and aryl compounds feature highly reactive, thermally labile [Ln–C] s-bonds which result in rapid and violent decomposition in the presence of air and moisture. Nevertheless, such [Ln–C] moieties display important intermediate species in numerous organic transformations. Reagents containing [Ln–C] bonds are deliberately generated in situ like Imamoto-type reagents Ln(III)Cl3/RLi (routinely at low temperatures) or “heavy” lanthanide-Grignard compounds RLnX. Samarium(III)-alkyl species are supposed intermediates of SmI2-promoted Barbier-type carbon– carbon coupling reactions. Alkyl/aryl ligand exchange at Ln(III) centers has been identified as the crucial step of lanthanide–halogenexchange reactions. In the meantime, several such mixed alkyl/halogenido complexes, devoid of an ancillary ligand, could be isolated and scrutinized with regard to structure and reactivity. More recently, Ln(III)-alkylidene complexes could be accessed, structurally authenticated and successfully employed in Tebbe-like olefination reactions of ketones.

Bayoud disease poses a significant threat to date palm cultivation, and finding effective antifungal solutions is of paramount importance. Our research represents a substantial advance in this field, as we have succeeded in identifying a dinuclear complex displaying a high inhibition activity of 97 % at a low concentration of only 81.1 μmol/L.

Abstract

New coordination compounds made of two novel tetrazole and C,N-bipyrazole ligands, 2-(3,5,5′-trimethyl-1′H-[1,3′-bipyrazol]-1′-yl)acetonitrile (L1), and 1′-((1H-tetrazol-5-yl)methyl)-3,5,5′-trimethyl-1′H-1,3′-bipyrazole (HL2), were prepared and fully characterized by spectroscopic techniques. Their crystal structures were identified by single-crystal X-ray diffraction revealing mononuclear complexes: [Ni(L1)₃](ClO₄)₂ (1), [Cd(L1)₂Cl₂] (2), [Cu(HL2)(L2)]ClO₄ (3), [Cu(L2)₂] (4) and a dinuclear complex [Co₂(HL2)(L2)Cl₃] (5) comprising Co^II ions in octahedral and tetrahedral surrounding within the same unit. Noticeably, 3 and 4 show different architectural structures due to ligand deprotonation as well as the effect of the counter anion. All compounds demonstrated antimicrobial activity against Gram (+) bacteria Listeria innocua and Staphylococcus aureus, as well as Gram (−) bacteria such as Escherichia coli and Pseudomonas aeruginosa, and antifungal activity against pathogenic fungi Geotrichum candidum, Aspergillus niger, and Penicillium crustosum. Interestingly, a high inhibition activity of 97 % was reached for 5 with a low concentration of only 81.1 μmol/L against Fusarium oxysporum f. sp. Albedinis, which is commonly damaging palm trees crops.

The synthesis of the dinuclear sulfide derivative [Ti(η⁵-C₅Me₅)Cl(μ-S)]₂ led to the formation of a series of dimetallic alkyl/aryl/amide sulfide-bridged complexes of titanium, [Ti(η⁵-C₅Me₅)R(μ-S)]₂. Hydrogenolysis, using phenyl and trimethylsilyl moieties, resulted in the quantitative generation of the Ti(III) tetrametallic sulfide cluster [Ti(η⁵-C₅Me₅)(μ₃-S)]₄. Alternatively, the treatment of the dimethylamide complex with SiH₃Ph, and the reaction of [Ti(η⁵-C₅Me₅)Cl(μ-S)]₂ with MgCl(C₃H₅), led to the formation of mixed-valence dinuclear systems.

Abstract

A series of dinuclear sulfur-bridged titanium derivatives [Ti(η⁵-C₅Me₅)R(μ-S)]₂ (R=NMe₂ (1), Ph (2), CH₂Ph (3), CH₂SiMe₃ (4)) has been synthesized from the reaction of [Ti(η⁵-C₅Me₅)Cl(μ-S)]₂ with the corresponding lithium salt or Grignard reagent. Formulation of 1–4 as symmetric dimers has been confirmed by crystallographic studies. The analogous reaction with Mg(C₃H₅)Cl afforded the paramagnetic mixed-valence Ti(III)/Ti(IV) compound [{Ti(η⁵-C₅Me₅)(μ-S)}₂(μ-C₃H₅)] (5). Contrasting with complexes 1–4, compound 5 exhibits a bridging μ-CH₂CHCH₂ fragment between the titanium atoms, which prevents the formation of a planar Ti₂S₂ core in the solid-state structure. Complex 1 reacts with SiH₃Ph to give [{Ti(η⁵-C₅Me₅)(μ-S)}₂(μ-NMe₂)] (6), a paramagnetic mixed-valence Ti(III)/Ti(IV) compound, structurally and electronically similar to 5. Under mild conditions, treatment of compounds 3 and 4 with H₂ (1 atm) generates quantitatively the Ti(III) tetrametallic sulfide cluster [Ti(η⁵-C₅Me₅)(μ₃-S)]₄, along with the corresponding alkane.

In this report, a Cu(II) complex Cu-L4 containing a new tetradentate benzotriazole-appended bipyridine ligand was synthesized and characterized fully via spectroscopic and crystallographic techniques. The crystal structure of the complex revealed that the ligand is bound to copper in a tetradentate fashion in a plane and the axial positions are occupied by an anion and a solvent molecule, resulting in a distorted octahedral geometry of the complex in solid-state. This air-stable complex was utilized as homogeneous precatalyst for the synthesis of several propargylamine derivatives by 3-component A3 coupling reactions of aldehydes, amines, and alkynes under aerial atmosphere.

The cytotoxicity, protein binding affinity, interactions with DNA, spectral and structural features of two new Ru(II) compounds, [RuCl(η⁶-p-cymene)(3-DNPH)] chlorido(η⁶-p-cymene)(3-nitrophenylhydrazine-k² N,N′)ruthenium(II) and [RuCl(η⁶-p-cymene)(3-CNPH)] chlorido(3-chlorophenylhydrazine-k² N,N′)(η⁶-p-cymene)ruthenium(II), are examined experimentally and theoretically.

Abstract

Ru(II)-arene compounds are being investigated as anticancer agents due to the biocompatibility of ruthenium and their structural diversity. Two newly synthesized Ru(II) complexes, [RuCl(η⁶-p-cymene)(3-DNPH)] (chlorido(η⁶-p-cymene)(3-nitrophenylhydrazine-k² N,N′)ruthenium(II)) (1) and [RuCl(η⁶-p-cymene)(3-CNPH)] (chlorido(3-chlorophenylhydrazine-k² N,N′)(η⁶-p-cymene)ruthenium(II)) (2), are experimentally (IR, NMR) and theoretically (B3LYP/6-31+G(d,p)(H,C,N,Cl)/LanL2DZ(Ru)) characterized. Experimental and theoretical values of ¹H and ¹³C chemical shifts and position of the most intense vibrational bands showed high correlation coefficients and low mean absolute errors, proving the predicted structure and applicability of the selected level of theory. Cell viability studies performed on MDA-MB-468, BT-474, and PC3 cells using MTT and CV assay indicated the activity of the second complex similar to the activity of cisplatin towards BT-474 breast cancer cells. The spectrofluorimetric measurements of Bovine Serum Albumin showed the binding process‘s spontaneity of complexes and protein, with a binding energy of around −30 kJ mol⁻¹. Detailed molecular docking analysis allowed the elucidation of the binding mechanism through specific intermolecular interactions. Both compounds showed a higher affinity towards BSA than naproxen and cisplatin. Molecular docking simulations proved the spontaneity of the complexes binding to DNA. Based on these promising results, further biological examinations of these compounds are advised.

The Front Cover shows a conceptual approach to the production of organophosphorus compounds in accordance with the main principles of “green chemistry” based on atom-economic click reactions of intermolecular insertion of various organic molecules into the phosphorus−phosphorus bond. The scope of the elaborated method is represented by a chamomile flower with organic substrates on the petals painted in the colors of the national flags of the international research team. The hard-working bees and butterflies bringing organic substrates represent the scientists who developed this type of unique chemistry. The ample opportunities of this powerful and environmentally friendly tool for the preparation of organophosphorus derivatives are shown by the great Volga River on the main background of the image. More information can be found in the Review by E. Hey-Hawkins, D. Yakhvarov, and co-workers.

The Cover Feature shows a small section of a layer in the structure of the new Li₄[Si(NCN)₄]. The solid-state metathesis reaction (SSM) of mixtures of SiI₄ and Li₂(CN₂) are controlled in situ by differential scanning calorimetry (DSC), revealing a polymeric reaction stage and the subsequent product formation under successive elimination of LiI. Tetracyanamidosilicates are closely related to orthosilicates and can exist with several cations of the PSE. As demonstrated in our previous research, metal tetracyanamidosilicates can act as robust host structures for luminescent materials to show second harmonic generation (SHG). More information can be found in the Research Article by H.-J. Meyer and co-workers.