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C13H10ClN3O, monoclinic, P21/c (no. 14), a = 19.0933(2) Å, b = 23.0910(3) Å, c = 10.6831(2) Å, β = 90.064(1)°, V = 4710.00(12) Å3, Z = 16, R gt(F) = 0.0411, wR ref(F 2) = 0.1081, T = 160 K.

C13H8Br2N2OS2, monoclinic, Pc (no. 7), a = 13.4050(4) Å, b = 4.7716(1) Å, c = 11.7303(4) Å, β = 105.885(3)∘$105.885{(3)}^{\circ }$, V = 721.66(4) Å3, Z = 2, Rgt${R}_{gt}$(F) = 0.0294, wRref$w{R}_{ref}$(F2 = 0.0808, T = 160 K.

C18H17BrF3N3S, triclinic, P1‾ $P\overline{1}$ (no. 2), a = 8.6380(2) Å, b = 14.5082(3) Å, c = 14.8000(3) Å, α = 98.177(2)°, β = 97.015(2)°, γ = 91.111(2)°, V = 1820.89(7) Å3, Z = 4, R gt(F) = 0.0296, wR ref(F 2) = 0.0783, T = 160 K.

C14H10ClN3O3, triclinic, P1 (no. 1), a = 4.8813(2) Å, b = 6.7806(2) Å, c = 10.3135(2) Å, α = 98.101(2)∘ $98.101{\left(2\right)}^{\circ }$ , β = 94.174(2)∘ $94.174{\left(2\right)}^{\circ }$ , γ = 97.612(3)∘ $97.612{\left(3\right)}^{\circ }$ , V = 333.515(18) Å3, Z = 1, Rgt ${R}_{gt}$ (F) = 0.0270, wRref $w{R}_{ref}$ (F2) = 0.0743, T = 160 K.

C20H22N4OS, triclinic, P1‾$P\overline{1}$ (no. 2), a = 6.8528(3) Å, b = 11.3498(5) Å, c = 13.3896(9) Å, α = 114.083(5)°, β = 104.326(4)°, γ = 90.369(3)°, V = 914.38(9) Å3, Z = 2, Rgt(F) = 0.0844, wRref(F2) = 0.2217, T = 160 K.

C14H12N4O3S, monoclinic, P21/n (no. 14), a = 12.2777(3) Å, b = 9.4312(2) Å, c = 12.9412(2) Å, β = 107.945(2)°, V = 1425.61(5) Å3, Z = 4, R gt(F) = 0.0305, wR ref(F 2) = 0.0837, T = 160 K.

C14H18F3N3S, monoclinic, P21/c (no. 14), a = 4.61919(4) Å, b = 29.1507(3) Å, c = 11.27803(10) Å, β = 94.4768(8)°, V = 1513.99(3) Å3, Z = 4, R gt(F) = 0.0588, wR ref(F 2) = 0.1579, T = 160 K.

Molecularly‐modified electrode materials that maintain stability over a broad pH range are rare. Typically, each electrochemical transformation necessitates a specifically tuned system to achieve strong binding and high activity of the catalyst. Here, we report the functionalisation of mesoporous indium tin oxide (mITO) electrodes with the macrocyclic host molecule pillar[6]arene (PA[6]). These electrodes are stable within the pH range of 2.4–10.8 and can be equipped with electrochemically active ruthenium complexes through host–guest interactions to perform various oxidation reactions. Benzyl alcohol oxidation serves as a model reaction in acidic media, while ammonia oxidation is conducted to assess the systems performance under basic conditions. PA[6]‐modified electrodes demonstrate catalytic activity for both reactions when complexed to different guest molecules and can be reused by reabsorption of the catalyst after its degradation. Furthermore, the system can be employed to perform subsequent reactions in electrolyte with varying pH, enabling the same electrode to be utilised in multiple different electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

The diagnosis and treatment of Chagas disease (CD) in the chronic phase remains a challenge. With that in mind, a potential theranostic device based on the trypanocidal agent known as megazol and the fac-M(CO)3+ (M = Re or 99mTc) fragment is proposed in the present work. The peripheral structure of megazol (LH,H) was modified to obtain the compounds LR1,R2 (R1 = H, R2 = Me and R1 = R2 = Me), which were used in the syntheses of complexes of composition [ReBr(CO)3LR1,R2]. These compounds were studied by elemental analysis, FTIR, UV-vis, NMR (1H and 13C), HR-ESI-MS, HPLC/UPLC and single-crystal XRD. The trypanocidal activity of the rhenium complexes was evaluated in vitro against the intracellular form of Trypanosoma cruzi. With exception of the [ReBr(CO)3LMe,Me] complex, all compounds are more active than the standard drug, benznidazole (Bzn), while [ReBr(CO)3LH,H] also exhibited a much higher selectivity index. In addition, the interaction of megazol and its ReI complex was evaluated with the T. cruzi Old Yellow Enzyme (TcOYE) by both experimental and computational methods. The data showed that megazol as well as its metal complex exhibited a higher affinity for TcOYE compared to Bzn. Finally, the labelling of megazol with 99mTc was successfully carried out. However, the results indicated that the Re complexes used as standards were not homologous with the 99mTc complexes. Despite this discrepancy, this research suggests that the investigation into Re and 99mTc complexes with megazol could lead to the development of a theranostic device for CD in a near future. [ABSTRACT FROM AUTHOR]

C18H18N4O5, monoclinic, P21/c (no. 14), a = 11.7553(8) Å, b = 6.4876(4) Å, c = 22.3442(15) Å, β = 91.263(7)°, V = 1703.64(19) Å3, Z = 4, Rgt (F) = 0.0531, wRref (F 2) = 0.1376, T = 160 K.

The benzimidazole moiety in the title molecule, C19H25N5O, is almost planar and oriented nearly perpendicular to the triazole ring. In the crystal, C—H...O hydrogen bonds link the molecules into a network structure. There are noμ-μinteractions present but two weak C—H...π(ring) interactions are observed. A Hirshfield surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H...H (62.0%), H...C/ C...H (16.1%), H...N/N...H (13.7%) and H...O/O...H (7.5%) interactions. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated via the dispersion energy contributions in the title compound. [ABSTRACT FROM AUTHOR]

The replacement of pyridyl by pyrazinyl in ligands of polypyridyl‐based cobalt water reducing catalysts (WRC) shifts reduction potentials anodically. Together with a new, trinuclear ReI photosensitizer, these WRCs show strongly improved photocatalytic performances in turnover numbers (TONs) and maximal H2 evolution rate. Depending on the catalyst structure, up to 65 kTONs at 1 μM WRC concentration were reached. Under electrocatalytic conditions in both DMF and H2O, one of the reported WRCs displays remarkable stability, producing H2 steadily over 21 and 14 d, respectively. [ABSTRACT FROM AUTHOR]

The search for new metal-based anticancer drug candidates is a fundamental task in medicinal inorganic chemistry. In this work, we assessed the potential of two new Ru(II)–phosphine–mercapto complexes as potential anticancer agents. The complexes, with the formula [Ru(bipy)(dppen)(Lx)]PF6 [(1), HL1 = 2-mercapto–pyridine and (2), HL2 = 2-mercapto–pyrimidine, bipy = 2,2′-bipyridine, dppen = cis-1,2-bis(diphenylphosphino)-ethylene] were synthesized and characterized by nuclear magnetic resonance (NMR) [1H, 31P(1H), and 13C], high resolution mass spectrometry (HR-MS), cyclic voltammetry, infrared and UV-Vis spectroscopies. Complex 2 was obtained as a mixture of two isomers, 2a and 2b, respectively. The composition of these metal complexes was confirmed by elemental analysis and liquid chromatography-mass spectrometry (LC-MS). To obtain insights into their lipophilicity, their distribution coefficients between n-octanol/PBS were determined. Both complexes showed affinity mainly for the organic phase, presenting positive log P values. Also, their stability was confirmed over 48 h in different media (i.e., DMSO, PBS and cell culture medium) via HPLC, UV-Vis and 31P{1H} NMR spectroscopies. Since enzymes from the P-450 system play a crucial role in cellular detoxification and metabolism, the microsomal stability of 1, which was found to be the most interesting compound of this study, was investigated using human microsomes to verify its potential oxidation in the liver. The analyses by LC-MS and ESI-MS reveal three main metabolites, obtained by oxidation in the dppen and bipy moieties. Moreover, 1 was able to interact with human serum albumin (HSA). The cytotoxicity of the metal complexes was tested in different cancerous and non-cancerous cell lines. Complex 1 was found to be more selective than cisplatin against MDA-MB-231 breast cancer cells when compared to MCF-10A non-cancerous cells. In addition, complex 1 affects cell morphology and migration, and inhibits colony formation in MDA-MB-231 cells, making it a promising cytotoxic agent against breast cancer. [ABSTRACT FROM AUTHOR]

In order to investigate the structural features and antiproliferative activity of Pd(II) complexes containing halogenated ligands with different flexibility, several Schiff base and reduced Schiff base Pd(II) complexes, namely X1X2PicPd, X1X2PyPd, X1X2Pic(R)Pd, and X1X2Py(R)Pd (where X1 = X2 = Cl, Br and I; Pic: 2-picolylamine; Py = 2-(2-pyridyl)ethylamine), were synthesized and characterized by spectroscopic methods and, in the case of Br2PyPd, Cl2Py(R)Pd and ClBrPy(R)Pd, also by X-ray crystallography. The results of the X-ray crystallography showed that in both series of complexes the Pd(II) ion has a distorted square-planar geometry, although the coordination modes of the two ligands are different. In the Schiff base-type complexes the ligand acts as a tridentate chelate with NN′O donor atoms, whereas in the reduced Schiff base-type complexes the ligand acts as a bidentate chelate with NN′ donor atoms. In both series of complexes, the chloride ions occupy the residual coordination sites of the Pd(II) ion. TD-DFT calculations were performed for a better understanding of the UV-Vis spectra. From these calculations it was found that the signal appearing at ∼400 nm in the complexes with reduced Schiff base ligands (X1X2Pic(R)Pd and X1X2Py(R)Pd) is mainly due to a HOMO → LUMO transition, while for the Schiff base complex ClBrPyPd the signal is due to a HOMO → LUMO+1 transition. For the complex I2PicPd, combinations of HOMO−4 → LUMO and HOMO−2 → LUMO transitions were found to be responsible for that signal. In regard to the biological activity profile, all complexes were first investigated as proteasome inhibitors by fluorometric methods. From these enzymatic assays, it emerged that they are good inhibitors with IC50 values in the low-micromolar range and that their inhibitory activity is strictly related to the presence of the metal ion. Subsequently they were also subjected to cell-based assays (the resazurin method) to assess their antiproliferative properties by using two leukemic cell lines, namely the drug-sensitive CCRF-CEM cell line and its multidrug-resistant sub-cell line CEM/ADR5000. In this test they displayed IC50 values in the sub-micromolar and low-micromolar range determined for a selected metal complex (Br2Pic(R)Pd) and ligand (Cl2Pic(R)), respectively. Moreover, docking studies were performed on the two expected molecular targets, i.e. proteasome and DNA, to shed light on the mechanisms of action of these types of Pd(II) complexes. [ABSTRACT FROM AUTHOR]

The benzimidazole entity of the title mol­ecule, C17H21N5O, is almost planar (r.m.s. deviation = 0.0262 Å). In the crystal, bifurcated C—H⋯O hydrogen bonds link individual mol­ecules into layers extending parallel to the ac plane. Two weak C—H⋯π(ring) inter­actions may also be effective in the stabilization of the crystal structure. Hirshfeld surface analysis of the crystal structure reveals that the most important contributions for the crystal packing are from H⋯H (57.9%), H⋯C/C⋯H (18.1%) and H⋯O/O⋯H (14.9%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the most dominant forces in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization of the title compound is dominated via dispersion energy contributions. The mol­ecular structure optimized by density functional theory (DFT) at the B3LYP/6–311 G(d,p) level is compared with the experimentally determined mol­ecular structure in the solid state. [ABSTRACT FROM AUTHOR]

The benzimidazole entity of the title mol-ecule, C17H21N5O, is almost planar (r.m.s. deviation = 0.0262 Å). In the crystal, bifurcated C-H⋯O hydrogen bonds link individual mol-ecules into layers extending parallel to the ac plane. Two weak C-H⋯p(ring) inter-actions may also be effective in the stabilization of the crystal structure. Hirshfeld surface analysis of the crystal structure reveals that the most important contributions for the crystal packing are from H⋯H (57.9%), H⋯C/C⋯H (18.1%) and H⋯O/O⋯H (14.9%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the most dominant forces in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization of the title compound is dominated via dispersion energy contributions. The mol-ecular structure optimized by density functional theory (DFT) at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure in the solid state. [ABSTRACT FROM AUTHOR]

Reactions of open‐shell molecular graphene fragments are typically thought of as undesired decomposition processes because they lead to the loss of desired features like π‐magnetism. Oxidative dimerization of phenalenyl to peropyrene shows, however, that these transformations hold promise as a synthetic tool for making complex structures via formation of multiple bonds and rings in a single step. Here, we explore the feasibility of using this "undesired" reaction of phenalenyl to build up strain and provide access to non‐planar polycyclic aromatic hydrocarbons. To this end, we designed and synthesized a biradical system with two phenalenyl units linked via a biphenylene backbone. The design facilitates an intramolecular cascade reaction to a helically twisted saddle‐shaped product, where the key transformations—ring‐closure and ring‐fusion—occur within one reaction. The negative curvature of the final peropyrene product, induced by the formed eight‐membered ring, was confirmed by single‐crystal X‐ray diffraction analysis and the helical twist was validated via resolution of the product's enantiomers that display circularly polarized luminescence and high configurational stability. [ABSTRACT FROM AUTHOR]

Abundantly available biomass‐based platform chemicals, including 5‐hydroxymethylfurfural (HMF), are essential stepping stones in steering the chemical industry away from fossil fuels. The efficient catalytic oxidation of HMF to its diacid derivative, 2,5‐furandicarboxylic acid (FDCA), is a promising research area with potential applications in the polymer industry. Currently, the most encouraging approaches are based on solid‐state catalysts and are often conducted in basic aqueous media, conditions where HMF oxidation competes with its decomposition. Efficient molecular catalysts are practically unknown for this reaction. In this study, we report on the synthesis and electrocatalysis of surface‐bound molecular ruthenium complexes for the transformation of HMF to FDCA under acidic conditions. Catalyst immobilisation on mesoporous indium tin oxide electrodes is achieved through the incorporation of phosphonic acid anchoring groups. Screening experiments with HMF and further reaction intermediates revealed the catalytic route and bottlenecks in the catalytic synthesis of FDCA. Utilising these immobilised electrocatalysts, FDCA yields of up to 85 % and faradaic efficiencies of 91 % were achieved, without any indication of substrate decomposition. Surface analysis by X‐ray photoelectron spectroscopy (XPS) post‐electrocatalysis unveiled the desorption of the catalyst from the electrode surface as a limiting factor in terms of catalytic performance. [ABSTRACT FROM AUTHOR]

Four Ni4O4 cubanes with formula [Ni4(Cl2-L)4(μ3-OMe)4(MeOH)4] (1), [Ni4(Br2-L)4(μ3-OMe)4(MeOH)4] (2), [Ni4(I2-L)4(μ3-OMe)4(MeOH)4] (3) and [Ni4(BrCl-L)4(μ3-OMe)4(MeOH)4] (4) (Cl2-LH = 3,5-dichlorosalicylaldehyde, Br2-LH = 3,5-dibromosalicylaldehyde, I2-LH = 3,5-diiodosalicylaldehyde, BrCl-LH = 3-bromo-5-chlorosalicylaldehyde) were obtained by self-assembly from commercially available 3,5-halogen-substituted salicylaldehydes and NiCl2·6H2O in high yields at room temperature. The X-ray crystal structure analysis of 4 showed a cubane-type structural topology as each Ni(II) ion is six-coordinated in a distorted octahedral geometry defined by four oxygen atoms from the MeOH molecule (three as bridging methoxy-oxygens and one as terminal group) and two oxygen atoms from the 3-bromo-5-chlorosalicylaldehyde ligands. The cubane core is stabilized via an intramolecular O–H⋯O hydrogen bond, while in the crystal, complex molecules are linked into the zigzag chain to the a-axis via strong Br⋯Br interaction. Both SQUID and μSQUID measurements indicate the coexistence of ferromagnetic and antiferromagnetic interactions in two complexes. The fitting of the magnetic data yields different magnetic parameters for each complex, clearly highlighting the differences in the magnetic properties among these systems. DFT calculations have also been performed on compounds 1–4 to explain the exchange interaction mechanisms between the Ni(II) ions, supporting both the magnitude and sign of the coupling constants. [ABSTRACT FROM AUTHOR]