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Infections of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have triggered a global pandemic with millions of deaths worldwide. Herein, the synthesis of functionalized Re(i) tricarbonyl complexes as inhibitors of the SARS-CoV-2 main protease, also referred to as the 3-chymotrypsin-like protease (3CLpro), is presented. The metal complexes were found to inhibit the activity of the enzyme with IC50 values in the low micromolar range. Mass spectrometry revealed that the metal complexes formed a coordinate covalent bond with the enzyme. Chiral separation of the enantiomers of the lead compound showed that one enantiomer was significantly more active than the other, consistent with specific binding and much like that observed for conventional organic small molecule inhibitors and druglike compounds. Evaluation of the lead compound against SARS-CoV-2 in a cell-based infection assay confirmed enantiospecific inhibition against the virus. This study represents a significant advancement in the use of metal complexes as coordinate covalent inhibitors of enzymes, as well as a novel starting point for the development of novel SARS-CoV-2 inhibitors.

Pyrite, also known as fool's gold is the thermodynamic stable polymorph of FeS2. It is widely considered as a promising d-band semiconductor for various applications due to its intriguing physical properties. Marcasite is the other naturally occurring polymorph of FeS2. Measurements on natural crystals have shown that it has similarly promising electronic, mechanical, and optical properties as pyrite. However, it has been only scarcely investigated so far, because the laboratory-based synthesis of phase-pure samples or high quality marcasite single crystal has been a challenge until now. Here, we report the targeted phase formation via hydrothermal synthesis of marcasite and pyrite. The formation condition and phase purity of the FeS2 polymorphs are systematically studied in the form of a comprehensive synthesis map. We, furthermore, report on a detailed analysis of marcasite single crystal growth by a space-separated hydrothermal synthesis. We observe that single phase product of marcasite forms only on the surface under the involvement of H2S and sulphur vapor. The availability of high-quality crystals of marcasite allows us to measure the fundamental physical properties, including an allowed direct optical bandgap of 0.76 eV, temperature independent diamagnetism, an electronic transport gap of 0.11 eV, and a room-temperature carrier concentration of 4.14 × 1018 cm-3. X-ray absorption/emission spectroscopy are employed to measure the band gap of the two FeS2 phases. We find marcasite has a band gap of 0.73 eV, while pyrite has a band gap of 0.87 eV. Our results indicate that marcasite - that is now synthetically available in a straightforward fashion - is as equally promising as pyrite as candidate for various semiconductor applications based on earth abundant elements.

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]