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In the face of the recent pandemic and emergence of infectious diseases of viral origin, research on parasitic diseases such as malaria continues to remain critical and innovative methods are required to target the rising widespread resistance that renders conventional therapies unusable. The prolific use of auxiliary metallo-fragments has augmented the search for novel drug regimens in an attempt to combat rising resistance. The development of organometallic compounds (those containing metal-carbon bonds) as antimalarial drugs has been exemplified by the clinical development of ferroquine in the nascent field of Bioorganometallic Chemistry. With their inherent physicochemical properties, organometallic complexes can modulate the discipline of chemical biology by proffering different modes of action and targeting various enzymes. With the beneficiation of platinum group metals (PGMs) in mind, this review aims to describe recent studies on the antimalarial activity of PGM-based organometallic complexes. This review does not provide an exhaustive coverage of the literature but focusses on recent advances of bioorganometallic antimalarial drug leads, including a brief mention of recent trends comprising interactions with biomolecules such as heme and intracellular catalysis. This resource can be used in parallel with complementary reviews on metal-based complexes tested against malaria.

Glioblastoma (GBM) is the most frequent and deadliest primary brain cancer in adults, justifying the search for new treatments. Some members of the iron-based ferrocifen family have demonstrated a high cytotoxic effect on various cancer cell lines via innovative mechanisms of action. Here, we evaluated the antiproliferative activity by wst-1 assay of six ferrocifens in 15 molecularly diverse GBM patient-derived cell lines (PDCLs). In five out of six compounds, the half maximal inhibitory concentration (IC50) values varied significantly (10 nM < IC50 < 29.8 µM) while the remaining one (the tamoxifen-like complex) was highly cytotoxic against all PDCLs (mean IC50 = 1.28 µM). The pattern of response was comparable for the four ferrocifens bearing at least one phenol group and differed widely from those of the tamoxifen-like complex and the complex with no phenol group. An RNA sequencing differential analysis showed that response to the diphenol ferrocifen relied on the activation of the Death Receptor signaling pathway and the modulation of FAS expression. Response to this complex was greater in PDCLs from the Mesenchymal or Proneural transcriptomic subtypes compared to the ones from the Classical subtype. These results provide new information on the mechanisms of action of ferrocifens and highlight a broader diversity of behavior than previously suspected among members of this family. They also support the case for a molecular-based personalized approach to future use of ferrocifens in the treatment of GBM.

A series of diiron/tetrairon compounds containing a S- or a Se-function ( - , - , - , ), and the monoiron [FeCp(CO){SeC (NMe )C HC (Me)}] ( ) were prepared from the diiron μ-vinyliminium precursors [Fe Cp (CO)( μ-CO){ μ-η : η -C (R')C HC N(Me)(R)}]CF SO (R = R' = Me, ; R = 2,6-C H Me = Xyl, R' = Ph, ; R = Xyl, R' = CH OH, ), via treatment with S or gray selenium. The new compounds were characterized by elemental analysis, IR and multinuclear NMR spectroscopy, and structural aspects were further elucidated by DFT calculations. The unprecedented metallacyclic structure of was ascertained by single crystal X-ray diffraction. The air-stable compounds ( , - , - , ) display fair to good stability in aqueous media, and thus were assessed for their cytotoxic activity towards A2780, A2780cisR, and HEK-293 cell lines. Cyclic voltammetry, ROS production and NADH oxidation studies were carried out on selected compounds to give insights into their mode of action.

The cover picture shows the crystal structure formed from a {RuII(η6‐p‐cymene)} complex featuring a thiomorpholine substituent and the nucleosome core particle. The photograph featured as the background was taken on the North Island of New Zealand and shows the ‘Champagne Pool’ within the Waiotapu geothermal area, with the orange color coming from deposits of arsenic and antimony sulfides. Details are given in the Full Paper by C. G. Hartinger and co‐workers on page 841 in Issue 6, 2017 (DOI: 10.1002/cplu.201700050).

Piano-stool iridium complexes based on the pentamethylcyclopentadienyl ligand (Cp*) have been intensively investigated as anticancer drug candidates and hold much promise in this setting. A systematic study aimed at outlining the effect of Cp* mono-derivatization on the antiproliferative activity is presented here. Thus, the dinuclear complexes [Ir(η5-C5Me4R)Cl(μ-Cl)]2 (R = Me, 1a; R = H, 1b; R = Pr, 1c; R = 4-C6H4F, 1d; R = 4-C6H4OH, 1e), their 2-phenylpyridyl mononuclear derivatives [Ir(η5-C5Me4R)(kN,kCPhPy)Cl] (2a–d), and the dimethylsulfoxide complex [Ir{η5-C5Me4(4-C6H4OH)}Cl2(κS-Me2S=O)] (3) were synthesized, structurally characterized, and assessed for their cytotoxicity towards a panel of six human and rodent cancer cell lines (mouse melanoma, B16; rat glioma, C6; breast adenocarcinoma, MCF-7; colorectal carcinoma, SW620 and HCT116; ovarian carcinoma, A2780) and one primary, human fetal lung fibroblast cell line (MRC5). Complexes 2b (R = H) and 2d (4-C6H4F) emerged as the most active ones and were selected for further investigation. They did not affect the viability of primary mouse peritoneal cells, and their tumoricidal action arises from the combined influence on cellular proliferation, apoptosis and senescence. The latter is triggered by mitochondrial failure and production of reactive oxygen and nitrogen species.

A series of 11 cymantrene and cyrhetrene nucleobase conjugates, together with the hitherto unreported N7 isomer of a ferrocene–adenine conjugate were synthesised and characterised. The synthetic approach involved a Michael addition reaction of in‐situ‐generated acryloylcymantrene, acryloylcyrhetrene and acryloylferrocene with the canonical nucleobases thymine, uracil and adenine. The mechanism of these reactions was investigated by means of density functional theory calculations. The products were characterised by spectroscopic and electrochemical methods. The molecular structure of one cymantrene–adenine conjugate in the solid state was determined by single‐crystal X‐ray structure analysis, confirming the N9‐substitution of the adenine moiety. It was found that the molecule adopts a bent conformation with the adenine and cyclopentadienyl planes in almost perpendicular orientation. The cymantrenyl nucleobases showed an irreversible redox behaviour, which is associated with ligand‐exchange reactions of the radical cationic species. The newly synthesised compounds were also tested for their activity against the protozoan parasite Trypanosoma brucei and human myeloid leukaemia HL‐60 cells. Some compounds showed promising antitrypanosomal activity, and most of them were non‐toxic to HL‐60 cells. It was also found that cymantrene and cyrhetrene ketone nucleobases were more active than their alcohol congeners. These findings indicate the potential of cymantrenyl and cyrhetrenyl nucleobase conjugates as possible lead compounds for future antitrypanosomal drug development. Say goodnight, parasite: Cymantrene, cyrhetrene and ferrocene nucleobase conjugates have been synthesized and studied by electrochemistry and DFT calculations. Some of these compounds exhibit significant activity against Trypanosoma brucei, a causative parasite of sleeping sickness (see figure).

Metallation of biomacromolecular species forms the basis for the anticancer activity of many metallodrugs. A major limitation of these compounds is that their reactivity is indiscriminate and can, in principle, occur in healthy tissue as well as cancerous tissue, potentially leading to side effects in vivo. Here we present pH-dependent intramolecular coordination of an arene-tethered sulfonamide functionality in organometallic ruthenium(II) ethylenediamine complexes as a route to controlling the coordination environment about the central metal atom. Through variation of the sulfonamide R group and the length of the tether linking it to the arene ligand the acidity of the sulfonamide NH group, and hence the pH-region over which regulation of metal coordination occurs, can be modulated. Intramolecular sulfonamide ligation controlled the reactivity of complex within the physiologically relevant pH-region, rendering it more reactive towards 5'-GMP in mildly acidic pH-conditions typical of tumour tissue compared to the mildly alkaline pH-conditions typical of healthy tissue. However, the activation of by ring-opening of the chelate was found to be a slow process relative to the timescale of typical cell culture assays and members of this series of complexes were found not to be cytotoxic towards the HT-29 cell line. These complexes provide the basis for the development of analogues of increased potency where intramolecular sulfonamide ligation regulates reactivity and therefore cytotoxicity in a pH-dependent, and potentially, tissue-dependent manner.

Inspired by the well-established clinical evidence about the interplay between apoptotic TRAIL (tumour necrosis factor-related apoptosis-inducing ligand) mechanism and reactive oxygen species (ROS)-mediated oxidative stress, a set of novel ONC201 hybrids containing the impiridone core and one or two differently positioned ferrocenylalkyl groups were synthesised in our present work. These two types of residues have been implicated in the aforementioned mechanisms associated with cytotoxic activity. A straightforward, primary amine-based synthetic approach was used allowing the introduction of a variety of -substituents into the two opposite regions of the heterocyclic skeleton. Reference model compounds with benzyl and halogenated benzyl groups were also synthesised and tested. The in vitro assays of the novel impiridones on five malignant cell lines disclosed characteristic structure-activity relationship (SAR) featuring significant substituent-dependent activity and cell-selectivity. A possible contribution of ROS-mechanism to the cytotoxicity of the novel metallocenes was suggested by density functional theory (DFT)studies on simplified models. Accordingly, unlike the -ferrocenylalkyl-substituted products, the compounds containing two ferrocenylalkyl substituents in the opposite regions of the impiridone core display a much more pronounced long-term cytotoxic effect against A-2058 cell line than do the organic impiridones including ONC201 and ONC212. Furthermore, the prepared -metallocene derivatives also present substantial activity against COLO-205- and EBC-1 cell lines.

The acylpyrazolone proligands HQ (HQ in general, in detail: HQ = 1-phenyl-3-methyl-4-carbonylcyclohexyl-5-pyrazolone, 4-C(O)-phenyl, HQ = 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, HQ = 1-phenyl-3-methyl-4-stearoyl-5-pyrazolone, HQ = 1-phenyl-3-stearyl-4-benzoyl-5-pyrazolone) were synthesized and reacted with (arene)Ru(II) acceptors affording complexes [(arene)Ru(Q )Cl] (arene = cymene (cym) or hexamethylbenzene (hmb)). The complexes were characterized by elemental analyses, thermogravimetric analysis-Differntial Thermal Analysis (TGA-DTA), IR spectroscopy, ESI-MS and H, and C NMR spectroscopy. Complexes [(arene)Ru(Q )Cl] where Q = Q and Q , due to the long aliphatic chain in the ligand, afford nanometric dispersions in methanol via self-assembly into micellar aggregates of dimensions 50-200 nm. The antibacterial activity of the complexes was established against Escherichia and Staphylococcus , those containing the ligands with a long aliphatic chain being the most effective. The complexes were immobilized on polystyrene by a simple procedure, and the resulting composite materials showed to be very effective against and .

Hydroxypyr(id)ones constitute an emerging platform for the design of drug molecules, owing to their favorable biocompatibility and toxicity profiles. Herein, [RuII(η6‐p‐cymene)] complexes with 3‐hydroxy‐2‐pyridinone functionalized with morpholine and thiomorpholine, as a means often used in medicinal chemistry to alter the physicochemical properties of drug compounds, are reported. The compounds underwent hydrolysis of the Ru−Cl bond and the aqua species were stable for up to 48 h in aqueous solution, as observed by 1H NMR spectroscopy and ESI‐MS. The compounds formed adducts with amino acids and proteins through cleavage of the pyridinone ligand. Binding experiments to the nucleosome core particle by means of X‐ray crystallography revealed similar reactivity and exclusive binding to histidine moieties of the histone proteins. Preliminary cyclin‐dependent kinase 2 (CDK2)/cyclin A kinase inhibitory studies revealed promising activity similar to that of structurally related organometallic compounds. Designer drugs: The {RuII(η6‐p‐cymene)} complexes of 3‐hydroxy‐2‐pyridinone‐functionalized with morpholine and thiomorpholine display low cytotoxic activity (see figure). This is associated with ligand‐exchange reactions that result in cleavage of the pyridinone moiety from the ruthenium center.